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Isaac A. Kennedy, Thomas Hemscheidt, James F. Britten, and Ian D. Spenser Abstract: 1-Deoxy-D-xylulose(= 1-deoxy-D-threopentulose)is a precursor of thiamin (Vitamin B,) and of pyridoxine (Vitamin B6) in bacteria. The synthesis of a [2,3-13c2]bond-labeled sample of the compound, to be used for investigations of the biosynthesis of the two vitamins, is described. In aqueous solution 1-deoxy-Dxylulose exists mainly as the open chain ketone. In methanol solution the compound exists as a mixture of the open chain ketone and the two corresponding epimeric furanoses. In acid solution the compound yields a 2,3':3,2'-dianhydride, whose structure was established by dimeric anhydride, di-P-1-deoxy-D-xylulofuranose X-ray crystallography.
Key words: [2,3-'3~2]-1-deoxy-~-xylulose, di-P-1-deoxy-D-xylulofuranose 2,3':3,2'-dianhydride, 5-0-benzyl3,4-0-isopropylidene-1-deoxy-D-xylulose, 4-0-benzyl-2,3-0-isoproylidene-D-threose. RCsumC : Dans les bactCries, le 1-dCsoxy-D-xylulose(= 1-dksoxy-D-thrkopentulose)est un prkcurseur de la thiamine (vitamine B1) et de la pyridoxine (vitamine B6). On dCcrit la synthbse d'un Cchantillon de ce compost marque sur les liaisons [2,3-13c2]qui sera utilisC dans des Ctudes de la biosynthbse des deux vitamines. En solution aqueuse, le 1-dtsoxy-D-xyluloseexiste principalement sous la forme d'une chdne cktonique ouverte. En solution dans le mkthanol, le composC existe sous la forme d'un mClange de la chdne cCtonique ouverte et des deux furanoses kpimbres correspondants. En solution acide, le composC fournit un anhydride dimbre, le 2,3':3,2'-dianhydride du di-P-1-dCsoxy-D-xylulofuranose,dont on a dktermink la structure par diffraction des rayons X. Mots clks : [~,3-13~2]-1-d~soxy-~-xylu~ose, 2,3':3,2'-dianhydride du di-P-1-dksoxy-D-xylulofuranose,5-0benzyle-3,4-O-isopropylidbne-1-dtsoxy-~-xylulose, 4-0-benzyle-2,3-0-isoproylidbne-D-thrkose. [Traduit par la rkdaction]
Introduction
1-Deoxy-D-xylulose is described as a crystalline compound, C5HI0o4,mp 6143°C (I), 6243°C (3), [a], +46 (c 1, The natural occurrence of l - d e o x ~ - ~ - x ~ l u l (= o s el - d e o x ~ - ~ - H20)(1), +33.6 (c 1, H20)(3).Since the crystalline compound thre~~entulose) was first reported in 1976 (1). The compound shows strong carbony1 absorption at 1710 cm-' (2, 4), it folwas obtained from an isolate of Streptomyces hygroscopicus, lows that it exists as the open chain ketone (2). ~ - D ~ ~ ~ ~ and its structure and stereochemistry were deduced from its xylulose, mp 63450C, -33 (c 1, H,O) (3) showed simmass spectrum and on the basis of the identification of its reducilar characteristics. tion product as a mixture of 1-deoxy-D-xylitoland 1-deoxy-DThe appearance of three methyl singlets in the 'H NMR l~xitolyby comparison of their 'HNMRspectray GLC retention spectrum ((D20or [D,]DMSO) 8: 2.15 (go%), 1.31, 1.23 ppm times, and optical rotation values with those of authentic spec(together 20%, signal at 1-31more intense than signal at 1.23)) imens prepared from D-xylose and ~-lyxose,respectively (2). (2), ( ( ~ ~ 8:0 2.50 ) (72%), 1.69 (20%), 1.64 (6%); 3.75-4.70 It was subsequently found that a range of microorgan(4H, m) ppm) (3) leads to the conclusion that in solution the isms show enzymic activity leading to the formation of 1compoun~exists as a mixture in the open ,-hain ketone ~ ~ o x ~ - D - xas~well ~ u as ~ of o s1-deoxy-~-xylulose~ ~ by acyloin predominates over the two anomeric furanoses, one of which type condensation of pyruvic acid with D-glyceraldehydeor Lis more abundantthan the other. glyceraldehyde, respectively (3), a reaction that is catalysed by Several chemical syntheses of 1-deoxyxylulose have been pyruvate deh~drogenase(E.C. 1.2.4.1) (4) and is accompanied reported. Derivatives of the L-enantiomer,prepared from threby de~arbox~lation. Another enzyme, acetoin deh~drogenase onamide (5, 6), had been reported long before the compound (E.c. 1.1.1.5), found in the same microorganisms, generates 1had been isolated from natural sources. Two syntheses of 1deoxy-~-x~lulose or its enantiomer by reaction of D- or ~ - g l y deoxy-D-xylulose ([a];' +34 (c 1, H~o))were devised in conceraldehyde, respectively, with acetoin or methylacetoin nection with investigations of thiamin biosynthesis, one startinstead of with ~ ~ r u vacid, i c yielding acetaldehyde or acetone, ing with derivatives of ~ - ~ l ~ ~ ~ r a l d and e h yacetaldehyde, de respectively, as the second product (4). the other from D-arabinose (7). The former method was employed to prepare a sample of 1-deoxy-D-[l,l,l-2~,]xyluReceived February 15, 1995. lose, the latter to generate a sample of the [l,l,l,(RS)-52~4]derivative. Both of these labeled compounds were shown I.A. Kennedy, T. Hemscheidt, J.F. Britten, and I.D. Spenser.' to be incorporated into the thiazole nucleus of thiamin in Department of Chemistry, McMaster University, Hamilton, Escherichia coli (7). The latter compound served as a precurON L8S 4M 1, Canada. sor also of pyridoxine in E. coli (8). Another synthesis (9), Author to whom correspondence may be addressed. Teleleading to racemic 1-deoxyxylulose, starts from xylitol, a phone: (905) 525-9140, ext. 23245. Fax: (905) 522-2509. E-mail:
[email protected] meso compound. Can. J. Chern. 73: 1329-1337 (1995). Printed in Canada / Imprim6 au Canada
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Can. J. Chem. Vol. 73, 1995
methyl carbinols, [2,3-13~2]-5-~-benzyl-3,4-0-isoprop dene-I-deoxy-D-xylitol and -1yxitol (11) in 90% yield. The mixture was oxidized with pyridinium dichromate (24) to yield [2,3-13~2]-5-0-benzy~-3,4-~-isopropylidene-ldeoxy xylulose (12) in 88% yield. Acid hydrolysis removed the isopropylidene protecting group to give [2,3-13~2]-5-~-benzylldeoxy-D-xylulose (13) (yield 88%), which, on hydrogenolysis in the presence of 10% palladiudcarbon gave the desired product, [2,3-13~2]-1-deoxy-~-xylulose (14) in quantitative yield. Overall, 10 g bond labeled starting material (2) furnished 0.95 g bond labeled 1-deoxy-D-xylulose(14) (16% yield). In preparation for the labeled synthesis, the new steps of the above reaction sequence, from the key intermediate (10) to the Results and discussion final product (14), were explored with unlabeled material. Unlabeled 4-0-benzyl-23-0-isopropylidene-D-threose (18) The major determinant in the design of the synthesis of 13Cwas obtained in two steps from (-)-2,3-0-isopropylidenelabeled compounds is the availability of 13C-labeled starting D-threitol [(4R,5R)-4,5-di(hydroxymethyl)-2,2-dimethyl1,3materials that are not exorbitantly expensive. This factor dioxolane] (15) (Aldrich), by oxidation (15, 16) of the becomes ovemding when two contiguous carbon atoms in the monobenzyl derivative, (4R,5R)-5-benzyloxymethyl-4target compound are to be enriched with 13C. (16) (14). The This paper describes a synthesis of [2,3-13~2]-1-deoxy-~- hydroxymethyl-2,2-dimethyl-1,3-dioxolane xylulose (14) that starts with triethyl phosphono[l,2-'3~2]ace- utility of the tert-butyldimethylsilyl protecting group was also investigated. 4-0-(tert-butyldimethylsily1)-2,3-0-isopropytate (2), or from ethyl brom0[1,2-'~C,]acetate. Ethyl bromolidene-D-threose(19) was obtained from 15 via 17 in two analacetate is a convenient starting material for preparation of ogous steps (25). triethyl phosphonoacetate (1 1). Both doubly labeled comNonstereospecific Grignard methylation of the aldehyde pounds are commercially available. The key intermediate of group of 18or of 19 with methyl magnesium chloride yielded the route is 11,2-13~2]-4-0-benzyl-2,3-~-isopropylidene-~a diastereomeric mixture (5:2 and 3:2, respectively, for 20 and threose (lo), from which the target compound, [2,3-I3C2]-121) of 5-protected-3,4-0-isopropylidene-l-deoxy-~-xylitol deoxy-D-xylulose(14), is obtainable in four steps. The route to and -1yxitol. Oxidation of each of the two diastereomeric mix10 proceeds by a sequence that has been well explored in the tures, 20 or 21, either with pyridinium dichromate (24) or with preparation of the corresponding unlabeled compounds, oxalyl chloride - DMSO (26) gave the corresponding 5-proemploying the Sharpless titanium-catalyzed asymmetric tected-3,4-0-isopropylidene-1-deoxy-D-xylulose(22, 23) in epoxidation procedure, followed by Payne and Pummerer 90% and 78% yield, respectively. rearrangement (12, 13). Unlabeled 4-0-benzyl-2,3-0Conversion of the 5-tert-butyldimethylsilyl derivative (23) isopropylidene-D-threose (18) is accessible (14-16) in two steps from (-)-2,3-0-isopropylidene-D-threitol([4R,5R]-4,5into free 1-deoxy-D-xylulose(27), either stepwise, using tetrabutylarnmonium fluoride to yield 3,4-0-isopropylidene-1di(hydroxymethy1)-2,2-dimethyl-1,3-dioxolane)(IS), a comdeoxy-D-xylulose (26), followed by hydrolysis with dilute pound that is commercially available. acid, or directly, with sodium fluoride in HCl solution, gave Condensation of 0-benzylglycolaldehyde (1) with triethyl the final product in very poor (ca. 25%) yield. Silyl protection phosphono[1,2-13~2]acetate(2) (cf. refs. 17-19) under was therefore abandoned in favour of benzyl protection. conditions known to yield the E isomer exclusively (ref. 20, and footnote 9 of ref. 12) gave ethy 1 ~1,2-'3~2]-4-benzyloxy-~- Simultaneous removal of both the benzyl (27) and the isopropylidene (27, 28) protecting groups from 5-0-benzyl-3,4but-2-enoate (3) in 79% yield. Reduction with diisobutyl aluminium hydride (cf. refs. 19, 21) gave [1,2-13~2]-4-benzy- 0-isopropylidene-1-deoxy-D-xylulose (22) using boron trichloride gave the deoxypentulose (27) in poorer yield (26%) loxy-E-but-2-en-1-ol(4) in quantitative yield. This compound than stepwise removal of the two groups. Presumably side was subjected to the Sharpless asymmetric epoxidation procereactions occur and the reagent and the product form a comdure (cf. refs. 12, 13, 19, and 22), using D-(-)-diisopropyl plex that resists separation even after repeated addition of tartrate in the presence of titanium tetraisopropropoxide, givmethanol, followed by flash chromatography. Hydrogenolytic ing [l ,2-13~2]-(2~,3~)-4-benzyloxy-2,3-epoxybutan-l-ol (5) debenzylation of 5-0-benzyl-3,4-0-isopropylidene-1-deoxyin 86% yield. Payne and Pummerer rearrangements (12, 13) D-xylulose (22) gave 3,4-0-isopropylidene-1-deoxy-D-xyluthen yielded, in sequence, [1,2-13~2]-(2~,3~)-4-benzyloxy-1lose (26) in 95% yield, from which 1-deoxy-D-xylulose(27) phenylthiobutane-2,3-diol (6), then the corresponding 2,3was obtained in 75% yield by acid hydrolysis. Conversely, isopropylidene derivative, [l ,2-13~2]-(2~,3~)-4-benzyloxyacid hydrolysis of 5-0-benzyl-3,4-0-isopropylidene-12,3-0-isopropylidene-1-phenylthiobutane-2,3-diol(7), foldeoxy-D-xylulose (22) gave 5-0-benzyl-1-deoxy-D-xylulose lowed by the corresponding sulfoxide (8) and the gem-acetoxy (24) in 88% yield. Hydrogenolysis in the presence of PdIC sulfide (9). In basic solution the latter undergoes hydrolysis then gave the free 1-deoxy-D-xylulose(27) in 95% yield. The accompanied by inversion (13, 23), to yield the labeled key latter deprotection sequence was chosen for the labeled synintermediate, [1,2-13~2]-4-0-benzyl-2,3-~-isopropylideneD-threose ([4,4'-13~2]-(4~,5~)-5-benzyloxymethyl-4-formylthesis. When 1-deoxy-D-xylulose(27) was prepared from 3,4-02,2-dimethyl-l,3-dioxolane)(lO). The overall yield of 10 from isopropylidene-1-deoxy-D-xylulose(26) by acid hydrolysis, 6 was 71%. and the solution was concentrated without complete removal Grignard reaction of 10 with methyl magnesium chloride of acid, a crystalline compound was obtained whose physical gave a 2.5:l diastereomeric mixture of the corresponding None of these syntheses were suitable for the preparation of the 13C-labeledsample we required for our investigation of pyridoxine biosynthesis. What was needed was a sample of 1deoxy-D-xylulosebond-labeled with 13C at C-2,3, in order to test the direct incorporation of the substrate into pyridoxol without cleavage of the C-2,C-3 bond. This bond is one of only two bonds that are formed de novo when pyridoxine is derived from [1,2,3,4,5,6-'3~6]glucose (10). To prove that 1-deoxy-Dxylulose is a late intermediate on the route from glucose into pyridoxine, it must be shown that the intact C-2,3 bond of the deoxypentulose is incorporated into pyridoxine.
I
I
I
I
~
I I
I
, I
I
I
Kennedy et al.
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Scheme 1. Synthesis of [2,3-'3~,]-1-deoxy-~-xy~ulose (14) from 0-benzylglycolaldehyde (1) and triethyl [1,2-13~,]phosphonoacetate (2).= '~c-~~c.
CHNH
9
8
5
CH3
-
CH20Bn
Scheme 2. Synthesis of 1-deoxy-D-xylulose(27) from (-)-2,30-isopropy lidene-D-threitol(15).
CH20H
15
-
Ho+H H
CHO
CH2OH
16,17
CHO 1 18,19
CH3
:+H
OH CHNH
(Fig. 1) showed it to contain a non-crystallographic twofold axis relating the two furanose rings, which adopt puckered conformations, with the two methylene groups, C(5) and C(5'), out of plane towards the same side of the molecule. Intramolecular bonding is normal. The OH groups at C(4) and C(4') are strongly hydrogen bonded: The oxygen atom O(4) forms a hydrogen bond to HO(4') of one of the neighbouring dimers (at x + 1, y - 1, z: 2.888(1) A) and the H of O(4) interacts with the furanose ring oxygen, 0(5'), of another (atx, y - 1, z: 2.957(1) A). This results in a two-dimensional sheet perpendicular to the crystallographic c-axis, with the methyl groups (C(1) and C( 1')) on one face and the methylene groups (C(5) and C(5')) on the other. The crystallographic screw axes (2,) stack these sheets in the c-direction, with methylenes facing methylenes, and methyls intertwined with methyls. The atomic coordinates and equivalent isotropic temperature factors are listed in Table 1.
Experimental The starting material for the synthesis of 1-deoxy-D-xylulose (27) was a commercial product, (-)-2,3-0-isopropylideneD-threitol ((4R,5R)-4,5-di(hydroxymethyl)-2,2-dimethyl-1,3dioxolane) (15) (Aldrich). This was converted into 4-0-benzyl-2,3-0-isopropylidene-D-threose (18) as well as into 4-0(tert-butyldimethylsilyl)-2,3-O-isopropylidene-~-threose (19) in analogy with published procedures that were employed to synthesize the L-enantiomers. Monobenzylation of (15) (14) gave 4-0-benzyl-2,3-0-isopropylidene-D-threitol (16) from which 18 was obtained (15, 16) by Swern oxidation (26). Monosilylation of 15 (25) gave 4-0-(tert-butyldimethylsily1)2,3-0-isopropylidene-D-threitol(17), Swern oxidation of which gave 19 (25). constants (mp 145-146"C, [c11D20-55.2 (c 1, CH,OH)) were different from those reported (1,3) for 1-deoxy-D-xylulose (27). The structure of this compound was determined by X-ray crystallography. The compound was found to be di-P- 1-deoxyD-xylulofuranose 2,3':3,2'-dianhydride (30), a dimer of P-1deoxy-D-xylulofuranose (29). X-ray structure analysis of 30
(4R,5R)-5-Benzyloxymethyl-4-(2'-(RS)-hydroxyethyl)2,2-dimethyl-1,3-dioxolane( 5-0-benzyl-3,4-0-isopropylidene-1-deoxy-D-xylitolplus 5-0-benzyl-3,40-isopropylidene-1-deoxy-D-lyxitol ) (20) Methyl magnesium chloride (3 M in THF, Aldrich, 2 equivalents) was added dropwise to a stirred solution of 18 ([c1lD2O - 19.4 (c 1.30, CHC1,); lit. (16) [c11D2'of enantiomer +16.8 (C
Can. J. Chern. Vol. 73, 1995
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Scheme 3. Formation of di-P- 1-deoxy-D-xylulofuranose 2,3':3,2'-dianhydride (30) by dimerization of P-I-deoxy-Dxylulofuranose (29).
Fig. 1. Thermal ellipsoid diagram of 30. (50% probability for C and 0; hydrogen atoms are represented by circles of arbitrary size).
Table 1. Atomic coordinates (x104) and equivalent isotropic displacement parameters (A2 x lo3) for 30. Atom
x
Y
z
We@
"U(eq) is defined as one third of the trace of the orthogonalized U,, tensor.
128.4 (2x), 127.8 (2x), 108.9, 82.8, 82.3, 77.4, 73.7, 70.9, 70.5, 67.8, 67.3, 27.1, 26.8, 19.6, 19.1. Anal. calcd. for C15H2,04:C 67.64, H 8.33; found: C 67.39, H 8.13. 1.10, CHCI,)) (3.3 g, 13.2 mmol) in dry tetrahydrofuran (25 mL) at 0°C and stimng was continued overnight. After dilution with ether (40 mL), the mixture was poured carefully into an ice-cold saturated aqueous solution of ammonium chloride. The phases were separated and the aqueous layer was extracted with ether (2 X 20 mL). The organic extracts were combined, dried over anhydrous MgSO,, filtered, and evaporated. The residual oil was purified by flash chromatography (10% ethyl acetate -petroleum ether) to yield 3.2 g (91 %) of a 2.51 mixture of the two diastereomers 20. 'H NMR (200 MHz, CDCl,) 6: 1.13 (d, 3H, J = 6.3 Hz, CH,CHOH), 1.33 (s, 6H, (CH,),), 2.75 (br s, lH, OH), 3.33-3.8 1 (m, 4H, 2(OCH), (CH,O)), 3.954.05 (m, lH, CHOH), 4.53 (s, 2H, OCH,Ph), 7.26 (m, 5H, C6H5). 13cNMR (50.3 MHz, CDCl,) 6: 137.2,
(4S,5R)-4-Acetyl-5-benzyloxymethyl-2,2-dimethyl-1,3dioxolane (5-0-benzyl-3,4-0-isopropylidene-1-deoxy-Dxylulose) (22) Pyridinium dichromate (24) (8.60 g, 22.8 mmol) was added to a solution of 20 (3.0 g, 11.3 mmol) in DMF (15 mL) and the mixture was stirred for 24 h. Water (30 mL) was then added and the mixture extracted with ether (3 x 40 mL). The combined ether extract was washed with brine, dried over anhydrous MgSO, and concentrated to give an oily residue. Flash chromatography (10% ether - petroleum ether) of the residual oil gave the product (22) as a colourless oil (2.7 g, 90%). [a],,' - 16.4 (c 1.54, CH2Cl2).'H NMR (200 MHz, CDC1,) 6: 1.42 (s, 3H, CH,), 1.54 (s, 3H, CH,), 2.34 (s, 3H, CH,CO), 3.62-3.71 (m, lH, OCH), 3.73-3.79 (m, lH, OCHCO), 4.21
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Kennedy et al.
(s, 2H, OCH,), 4.63 (s, 2H, CH2C6H5),7.22-7.38 (m, 5 H, C6H5). 13cNMR (50.3 MHz, CDC13) 6: 208, 137.6, 128.1 (2x), 127.3 (3x), 110.7,81.6,77.0,73.2,69.9,26.6,26.1,26.0. Anal. calcd. for C,,H,,O,: C 68.16, H 7.63; found: C 68.06, H 71 1
5-0-Benzyl-1-deoxy-D-xylulose (24) 5-0-Benzyl-3,4-0-isopropylidene- 1-deoxy-D-xylulose (22) (1.0 g, 3.8 mmol) was dissolved in 50 mL of a solution prepared by mixing CH,CN, H20, and 2 M HCl in the ratio 90:6:3 (29). The mixture was stirred for 24 hand was then concentrated, and CH,Cl, (30 mL) was added. The solution was washed with saturated Na,CO, (2 x 5 mL) and brine. The organic layer was concentrated after drying over Na,SO, and chromatographed on silica gel (230400 mesh) using the following solvents: 50% ether - petroleum ether until a yellowish fraction came off, then CH2C12, and finally 5% methanol - CH2Cl2to afford 0.75 g (87%) 24 as a colourless oil. [alDZ0+51.6 (c 1.32, CH2C12).'H NMR (200 MHz, CDC13) 6: 2.22 (s, CH,), 2.34 (d, lH, J = 7.7 Hz, OH), 3.55 (m, lH, CH), 3.58 (s, lH, OH), 3.65 (d, lH, J = 4.5 Hz, COCH), 4.13-4.19 (m, 2H, CH,O), 4.51 (s, 2H, 0CH2C6H5), 7.28 (m, 5H, C6H5). 13cNMR (50.3 MHz, CDC1,) 6: 208.1, 137.6, 128.4 (2x), 127.9, 127.8 (2x), 76.3, 73.6, 71.0, 70.4, 25.5. HRMS calcd. for C,,H,,O, (M' + 1): 225.1 127; found: 225.1123. Anal. calcd. for C12H,604'0.25H,O: C 63.00, H 7.27; found: C 62.65, 62.95; H 7.18,7.08.
(4R,5R)-5-0-(tert-Butyldimethylsilyl)oxymethyl-4-(2'(RS)-hydroxyethy1)-2,2-dimethyl-1,3-dioxoae (5-0(tert-butyldimethylsilyl)-3,4-0-isopropylidene-l-deoxyD-xylitolplus 5-0-(tert-butyldimethylsily1)-3,4-0-isopropylidene-1-deoxy-D-lyxitol) (21) Methyl magnesium chloride (1 M in THF, Aldrich, 3 equivalents) was added dropwise to a stirred solution of 19 (1.4 g) in dry THF (25 mL) at 0°C and the mixture was stirred overnight and allowed to reach room temperature. It was then refluxed for 1 h, cooled, diluted with cold ether (40 mL), and was then added dropwise to an ice-cold saturated aqueous solution of ammonium chloride (75 mL). The phases were separated and the aqueous phase was extracted with ether (3 x 50 mL). The organic extracts were combined, washed with water (2 x 40 mL) and saline (2 x 40 mL), dried over anhydrous MgSO,, filtered, and evaporated. The residual oil was purified by flash chromatography (10% ethyl acetate - hexane 1:3), followed by bulb-to-bulb distillation (oven temp. 140°C, 0.2 Torr; 1 Torr = 133.3 Pa). Yield 1.0 g, (70%) with respect to 19, mixture of two diastereomers ca. 3:2. Major, less polar diastereomer: -23.0 (c 2.89, CHCl,). 'H NMR: (500 MHz, CDC1,) 6: 0.1 (s, 6H, SiMe,), 0.9 (s, 9H, Si-tBu), 1.25 (d, 3H, J = 6.2 Hz, CH,CHOH), 1.38, 1.39 (2 x s, 6H, C(CH3),), 3.65 (m, 2H, SiOCH,), 3.8 (m, lH, OCH), 3.89 (m, 2H, OCH, CHOH). ',c NMR (75 MHz, CDCl,) 6: 108.9, 84.3,79.6,68.3, 64.4,27.1, 27.0,26.0, 19.5, 18.2, -5.4. MS(E1) d z : 275 (M' - CH,, lo%), 175 (25), 157 (14), 133 (14), 131 (93), 117 (57), 89 (ll), 83 (21), 75 (100). HRMS calcd. for C13H2,04Si(M' - CH,): 275.1679; found: 275.1672. Minor, more polar diastereomer: [a],'' -7.9 (c 1.58, CHCl,). 'H NMR: (500 MHz, CDC1,) 6: 0.065 (s, 6H, SiMe,), 0.89 (s, 9H, Si-tBu), 1.21 (d, 3H, J =6.2Hz, CH,CHOH), 1.39,
1.40 (2 x s, 6H, C(CH,),), 3.73 (m, 2H, SiOCH,), 3.8 (m, 2H, 2 OCH), 3.94 (m, lH, CHOH). ',c NMR (75 MHz, CDC1,) 6: 109.2,82.7,77.6,67.5,63.8,27.3,27.2,25.9, 19.7, 18.3, -5.5. MS(E1) d z : 275 (M'-CH,, 12%), 245 ( 3 , 187 (8), 175 (33, 157 (14), 131 (92), 117 (58), 99 (27), 83 (21), 75 (100). HRMS calcd. for C,,H,,O,Si (M'-CH,): 275.1679; found: 275.1692.
(4S,5R)-4-Acetyl-5-(tert-butyldimethylsilyl)oxymethyl2,2-dimethyl-1,3-dioxolane (5-0-(tert-butyldimethylsily1)-3,4-0-isopropylidene-1-deoxy-D-xylulose) (23) To a stirred solution of oxalyl chloride (0.3 1 mL, 3.6 mmol, 1.2 equiv.) in dry CH,Cl, (6 mL) at -78°C was added dropwise a solution of DMSO (0.5 mL, 7.2 mmol, 2.4 equiv.) in CH2C12(3 mL) over 5 min. After stimng for 15 min, a solution of 21 (0.9 g, 3.1 mmol) in dry CH,Cl, (6 mL) was added over 5 min. and stimng was continued for 2 h at -78°C. Triethylamine (1.7 mL, 12 mmol, 4 equiv.) in CH2C12(5 mL) was then added to the reaction mixture and the temperature was allowed to rise to room temperature over 1.5 h. The mixture was diluted with 5 volumes anhydrous ether, the solution was filtered through a Celite pad, and the filtrate was concentrated in vacuo. The residual oil was diluted with ether and washed with water (2 X 5 mL) and salt solution (5 mL). The ether layer was dried over MgSO,, filtered, and evaporated. The 5-0-(tert-butyldimethylsily1)-3,4-0-isopropylidene-1-deoxy-D-xylulose (23) so obtained was purified by flash chromatography with 10% ethyl acetate in hexane (Yield 0.7 g). -20.0 (c 2.23, CHC13). 'H NMR (500 MHz, CDC1,) 6: 0.09 (s, 6H, SiMe,), 0.9 (s, 9H, Si-tBu), 1.43, 1.46 (2 X s, 6H, C(CH,),), 2.29 (s, 3H, COCH,), 3.76 (dd, lH, J = 3.9, 11.3 Hz, CH,O), 3.88 (dd, lH, J = 3.5, 11.3Hz,CH20),4.06(m, lH,CHCH2),4.32(d, lH,J=7.5Hz, CHCO). I3cNMR (75 MHz, CDCl,) 6: 109.2,82.7,77.6,67.5, 63.8,27.3,27.2,25.9, 19.7, 18.3, -5.5. MS(E1) d z : 288 (M', 0.3%), 273 (M' - CH3, 3.2) 245 (14),231 (26), 187 (22), 173 (31), 145 (33,143 (23), 131 (31), 117 (loo), 101 (33), 89 (14), 86 (40), 84 (63), 75 (66), 73 (80). HRMS calcd. for C,,H2804Si: 288.1757; found: 288.1784.
(4S,5R)-4-AcetylS-hydroxymethyl-2,2-dimethyl-1,3-dioxolane (3,4-0-isopropylidene-1-deoxy-D-xylulose) (26) A. By debenzylation of 5-0-benzyl-3,4-0-isopropylidene-1deoxy-D-xylulose(22) A mixture of the benzyl ether 22 (0.16 g, 0.61 mmol) and preequilibrated 10% palladiumlcarbon (Aldrich, wet Degussa type) (0.1 g) in 95% ethanol (6 mL) was hydrogenated (30,31) for 3 hat room temperature and atmosphericpressure. The mixture was filtered through Celite, and the filtrate evaporated at reduced pressure to afford a white solid. The solid residue was redissolved in a small amount of MeOH and applied to a column of alumina (neutral, Brockrnann, Activity l), equilibrated with CH,Cl,. The column was washed with 5% MeOH in CH2C12.The product (0.10 g, 95%) slowly formed a semisolid mass upon evaporation of the solvent. [alDZ0- 19.2 (c 1.83, CH30H). 'H NMR (200 MHz, CDCl,) 6: 1.37 (s, 3H, CH,), 1.41 (s, 3H, CH,), 2.25 (s, 3H, CH,CO), 2.22 - 2.36 (br s, lH, OH), 3.66 (dd, lH, J = 12.0,4.1 HZ,0-CHH), 3.84 (dd, lH, J = 12.0,3.4H~,O-CHH),4.04(ddd, lH, J=7.9,4.1,3.4Hz,OCH-CH,), 4.20 (d, lH, J =7.9 Hz, 0-CH-CO). 13cNMR (50.3 MHz, CDC1,)S: 209.1,110.7,81.6,78.0,62.2,26.7,26.5,26.0.
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Can. J. Chem. Vol. 73, 1995
B. By desilylation of 5-0-(tert-butyldimethylsily1)-3,4-0-isopropylidene-l -deoxy-D-xylulose(23) A 0.4 M solution of 23 (0.1 g) in THF was reacted with a 1 M solution of tetrabutylammonium fluoride (2 equiv.) in THF at 0°C with stirring under nitrogen. The progress of the reaction was monitored by TLC (silica gel, pet. ether - ethyl acetate 7:3). When reaction appeared complete (ca. 1 h) the mixture was concentrated in vacuo and the residue applied to a column of alumina (neutral, Brockmann, Activity 111), equilibrated with CH2C12.The column was washed with two bed volumes of CH2C12and was then eluted with two bed volumes each of 1% MeOH in CH2C12,2% MeOH in CH2C12and 3% MeOH in CH2C12.The product, obtained in poor yield (2&25%) upon evaporation of the solvent, elutes in the 2% and 3% fractions. A similarly poor yield of 1-deoxy-D-xylulose (27) wa obtained when 23 was simultaneously desilylated and hydrolyzed with aqueous HF.
Method A Acid hydrolysis of 3,4-0-isopropylidene- 1-deoxy-D-xylulose (26) (100mg, 0.57 mmol) with2MHClinacetonitrile, following the procedure for the conversion of 22 into 24, gave 1-deoxy-Dxylulose (27) (58 mg, 75%), together with a number of unidentified byproducts that gave discrete spots on TLC. One of these by-products, which was obtained in 10% yield (13 mg), was isolated as acrystalline compound and identified as 30 (see below). Method B Hydrogenolysis of 5-0-benzyl-1-deoxy-D-xylulose (24) (0.50 g, 2.2 mmol) in the presence of Pd/C (see conversion of 22 into 26) gave 1-deoxy-D-xylulose(27) (0.29 g, 97%). Method C Boron trichloride (1 M in CH2C12,Aldrich, 2.4 mL, 2.4 mmol) (27, 28) was added dropwise to a solution of 5-0-benzyl-3,40-isopropylidene-1-deoxy-D-xylulose(22) (0.13 g, 0.49 mmol) in CH2C12(2 mL) at -78°C. The reaction mixture was warmed to 0°C for 30 min. and then to room temperature for an additional 30 min. Excess BCl, was removed under vacuum and 95% aqueous methanol (10 mL) was added and the mixture concentrated. This process was repeated and the crude concentrate chromatographed on neutral alumina (1% MeOH - CH2C1,) to afford a mixture of the cyclized products (28 and 29) as an oil (17 mg, 26%). In aqueous solution, the product exists mainly as the open chain deoxypentulose 27 (66%), together with a 1:1 mixture of the anomeric a and p furanoses 28 and 29 (33%). [alDZ0+22.4 (c 1.10, ~ ~ 0 )(lit. ; ' (7) [a],21 4-34 (c 1, H20)). 'H NMR (200 MHz, D20) 6: 1.35, 1.39 (anomers), 2.21 (open chain)(total 3H, 3 s, in the ratio 16:15:67, CH,), 3.52-3.78 (m, 2H, OCH,), 4.074.33 (m, 2H, CHCH). ',c NMR (50.3 MHz, H20) 6: 216.7,79.7,74.0,64.7, 28.2. In methanol solution the product exists mainly as a 1:l mixture of the two oily cyclized products 28 and 29 (17 mg, 26%). 'H NMR (200 MHz, CD,OD) 6: 1.27 (s, CH,), 1.32 (s, CH,)(anomeric ratio ca. 1:1), 3.19-3.23 (m, 2H, 2(OH)), The value of [a],was found to vary from preparation to preparation, due to variation in the proportions of the open chain (27) and furanose (28,29) forms that were present.
3.29-3.33 (m, 4H, 2 x 2(OH)), 3.45-3.74 (m, 4H, 2 x CH20), 3.904.20 (m, 4H, 2 x (CH, CH)). 13cNMR (50.3 MHz, CD,OD) 6: 110.4, 105.9; 85.1, 83.8; 79.2. 77.8; 72.8, 71.6; 19.1, 16.9 (ratio of anomers 1: 1).
Di-P-1-Deoxy-D-xylulofuranose 2,3':3,2'-dianhydride (30) The dimeric compound (30) was obtained as colourless crystals in 10% yield as a by-product in the preparation of 27 from 26 by acid hydrolysis (method A). It was recrystallized from methanol/CH2C12. Melting point: 145-146°C. [alDZ5-55.2 (c 1, CH,OH). 'H NMR (200 MHz, CD,OD) 6: 1.41 (s, 6H 2xCH3),
3.60-3.70(m,4H,2xCH20),4.02(m,2H,2xCHOH),4.12 (d, 2H, J=2.7 Hz, 2 x CH), 4.78 (s, 2H, 2 x OH). 13cNMR (50.3 MHz, CD,OD) 6: 105.0,83.0,77.9,74.3,21.6. Anal. calcd. for Cl0HI6o6:C 51.72, H 6.95; found: C 51.09, H 6.84. Crystal data: CioH1606 fw = 232.23 Monoclinic, a = 6.2580(10), b = 7.999(2), c = 10.547(2) A, P = 90.52(3)", V=527.9(2)A3,Z=2, p c = 1.461 gcm-,, p=0.121 mm-' (296(2)" K, MoKa,, A = 0.71073 A). A single crystal of 30 (0.40 x 0.25 x 0.08 mm3) was glued to a glass fibre. X-ray diffraction data were collected on a Siemens P4 diffractometer with a Mo rotating anode. Variable speed scans (4" - 60°/min in w, 0.37" in w on either side of the K a split) were used for 8-28 scans of the full sphere of reflections in the range 3.5" < 20 < 60.0". Three standard reflections were measured after every 97 measurements. No decay was observed. 3386 reflections were collected, and 186 low-angle reflections were recollected at lower power to determine the intensities of several reflections that had overflowed the counter (scale factor = 6.5). Merging of the data resulted in 2953 independent reflections (R,, = 0.019). Absorption and extinction corrections were not required. The SHELXTLprograms (32) were used for structure solution, refinement, and preparation of diagrams and tables. Direct methods provided a model of all non-hydrogen atoms in the polar space group P2,. Anisotropic refinement and a difference Fourier synthesis revealed.al1hydrogen atoms, which were subsequently refined isotropically. Full-matrix weighted leastsquares refinement on F' of 209 parameters using 2953 reflections with F2> -3u gave a goodness of fit S = 1.043 and a wR2 = 0.088, where S = [ Z [ W ( F ~ ~:)~]l(rn-n)]"~ form reflections 2 2 112 and n parameters; wR2 = [ C [ W ( F ~ - F:)~]/c[w(F, ) 11 ;and w = 1/[C2(F:) + (0.0597~)~], P = [ m a x ( 0 , ~ ~ ) /+3 ][2~:/3]. The traditional R equals 0.035, for all values of F. The largest difference peak and hole were 0.226 and -0.192 e/A3.The absolute configuration of 30 follows from that of its precursor (27) whose synthesis from starting materials of known absolute configuration is here described. Scattering factors (33) and anomalous scattering corrections (34) were taken from International Tables for Crystallography, Vol. c., Tables of bond lengths and angles, of anisotropic temperature factors, of hydrogen atom parameters, of torsion angles, and of least-squares planes may be purchased from: The Depository of Unpublished Data, Document Delivery, CISTI, National Research Council Canada, Ottawa, Canada KIA 0S2. Tables of bond lengths, bond angles, and hydrogen atom parameters have also been deposited with the Cambridge Crystallographic Data Centre, and can be obtained on request from The Director, Cambridge Crystallographic Data Centre, University Chemical Laboratory, 12 Union Road, Cambridge, CB2 lEZ, U.K.
Kennedy et al.
Synthesis of [2,3-13~,]-1-deoxy-~-x lulose (14) The starting materials, ethyl [1,2-' C,]bromoacetate (Carnbridge Isotopes), triethyl [1,2-'3~2]phosphonoacetate (2) (Aldrich), and 0-benzylglycolaldehyde (benzyloxyacetaldehyde (Aldrich)) (I), were commercial products. Ethyl [1,2-'3~2]bromoacetate was converted into triethyl [1,2-'3~2]phosphonoacetate (2) in 95% yield by a published method (1 I ) . Each ~ step in the synthetic sequence leading to the labeled end product was performed repeatedly on a small scale. The products of individual preparations of a given intermediate were combined for the next step, when necessary. A total of 10 g 2 was converted into 0.95 g 14, a net yield of 16%.
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B
Triethyl [1,2-13~2]phosphonoacetate (2): bp 100-102°C at 0.6 torr (lit. (1 1) bp 109-109.5"C at 0.8 torr). 'H NMR (200 MHz, CDC1,) 6: 1.25 (t, 3H, J = 7.1 Hz, ester CH2CH3),1.31 (t, 6H, J = 7.1 HZ, 2(PO-CH2CH3)),2.92 (ddd, 2H, ' ~ 1 =3 128.9 ~ ~ HZ,JPFH = 21.6 HZ, 2 ~ 1 3 C , H= 7.4 HZ, ' 3 ~ ~ 2 ' 4.06 3 ~~ 4.23 ) , (m, 6H, 3(0CH2CH3). I3C NMR (50.3 MHz, CDC1,) 6: 165.8 = 58.4 HZ,Jlsc,p = 7.0 HZ),62.7,62.6, 61.5, 34.3 (dd, , IHZ), ~ 16.3, ~ 16.2, 14.0. (dd, J13C,p = 134.5 HZ,J I ~ =~58.4
~
(br s, lH, OH), 4.12 (dm, 2H, J = 148.4 Hz, ',cH~-o), 5.89 (dm, 1H, J = 148.9 Hz, =',cH), 5.74-5.90 (m, 1H, =CH), 7.26-7.39 (m, 5 H, C6H5). ',c NMR (50.3 MHz, CDC1,) 6: 138.1, 132.2 (d, J = 45.9 Hz), 128.4 (2x), 127.7 (2x), 127.6, 72.3,70.1,62.9 (d, J=46.0 Hz). MS (CI) d z : 198 (M'+NH3, loo%), 163 (M' + H - H20, 11).
[1,2-13~2]-(2~,3~)-4-~enzy1o~Y-2,3-epoxybutan-l-ol ([1,213~2]-(2~,3R)-4-benzyloxymethyl-2-hydroxymethyl-2,3oxirane) (5)(12, 19, 22) To a solution of methylene chloride (80 mL) at -20°C was added sequentially titanium tetraisopropropoxide (2.8 mL, 9.35 mmol) and D-(-)-diisopropyl tartrate (2.5 mL, 11.7 mmol) in methylene chloride (5 mL) and the mixture stirred for 10 min. [l,2-'3~2]-4-~enzyloxy-~-but-2-en-l-ol (4) (1.5 g, 8.3 mmol) in methylene chloride (5 mL) was added and the mixture stirred for 2 h at -20°C and then stored overnight at - 18°C. After 18 h, aqueous saturated Na2S04solution (8 mL) and ether (8 mL) were added to the reaction mixture, which was stirred for 1 h at 22°C. After filtration through Celite, the filtrate was concentrated and diluted with ether (63 mL). 1 N NaOH solution (14 mL) was added to the ethereal solution and the resulting mixture stirred 30 min at 0°C. The ether layer was separated and the aqueous layer washed with ether ( 2 ~ ) . The combined ether extracts were washed with brine, dried, and concentrated. Chromatography (20% ethyl acetate petroleum ether) on silica gel (230-400 mesh) gave 5 as a colourless oil (1.4 g, 86%). [alD20+28.8 (c 1.68, CH2C12)(lit. (14) of enantiomer: -21 (c 0.97, CHCl,)). 'H NMR (200 MHz, CDC1,) 6: 2.13 (br s, lH, OH), 2.60-3.37 (m, 2H, 0-CH, 0-CHH), 3.43-3.79 (m, 3H, ',cH,-oH, 0-CHH), 3.904.41 (m, lH, o-',cH), 4.57 (AB q, 2H, J = 12.1 Hz, OCH,), 7.32-7.38 (m, 5H, C6H5).',c NMR (50.3 MHz, CDC1,) 6: 137.7, 128.4 (2x), 127.7 (2x), 73.3, 69.6, 61.1 (d, J = 46.2 Hz), 55.7 (d, J = 46.2 Hz), 54.4. MS (EI) d z : 195 (M' - H, 5%), 177 (3), 107 (92), 91 (100); (CI) d z : 214 (M' + NH,, 100%). HRMS calcd. for ' 3 ~ 2 ~ , (M' ~,3 -0 H):3195.0932; found: 195.0962.
Ethyl [1,2-13~~]-4-benzyloxy-~-but-2-enoate (3) (17-19) Triethyl [l,2-'3C2]phosphonoacetate (2) (2.0 g, 8.9 mmol, Aldrich) in benzene (6 mL) was added dropwise over 20 min to a suspension of NaH (220 mg, 9 mmol) in benzene (30 mL) at 22°C. The mixture was stirred for 1.5 h at 22°C and O-benzylglycolaldehyde (1) (1.35 g, 9.0 mmol, Aldrich) in benzene (5 mL) was added dropwise over 10 min. A gelatinous precipitate began to form as the aldehyde was added. The mixture was stirred for 3 h, water was added, and the layers separated. The aqueous layer was washed with ether (3x) and the combined organic extracts were dried over MgSO,. Concentration followed by chromatography (5% ether - hexanes) on silica gel (230400 mesh) gave 3 (1.5 g, 78%) as a colourless oil. 'H NMR (200 MHz, CDCI,) 6: 1.25 (t, 3H, J = 7.1 Hz, OCH,CH,), 4.104.23 (m, 4H, CH2-CH=, 0-CH2CH3), 4.52 (S, 2H, CH2-C6H5),6.1 1 (tddd, lH, J13C,H = 164.0 HZ, 3JH,H = 15.8 Hz, 2 ~ ~ s C = ,3.3, H 2 ~ H , H= 2.0 HZ, 13C-H), 6.88-7.05 (m, lH, C-H), 7.27-7.34 (m, 5 H, C6H5). 13cNMR (50.3 HZ, CDCI,) 6: 166.2 (d, J = 75.49 Hz), 144.1 (d, J = 70.5 Hz), [1,2-13~2]-(2~,3~)-4-~enzyloxy-~-phenylthiobutane-2,3137.6, 128.4 (2x), 127.7, 127.5 (2x), 121.3 (d, J = 75.5 Hz), diol(6) (12) 72.6, 68.5 (d, J = 6.0 Hz), 60.3, 14.2. MS (EI) d z : 222 (M', A solution of the epoxide 5 (580 mg, 3.0 mmol) in tert-butanol I%), 193 (2), 110 (lo), 91 (100); (CI) d z : 240 (M' + NH,, (15 mL) was mixed with a 0.5 M NaOH solution (15 mL, 7.5 loo%), 223 (M' + 1, 16). HRMS calcd. for ' 3 ~ 2 ~ 1 1 ~ 1 6 mrnol) ~ 3 : and nitrogen gas was passed vigorously through the 222.1 166; found: 222.1 166. mixture for 40 min. The mixture was then heated to reflux in a nitrogen atmosphere and thiophenol (400 kL, 40 mmol) in [1,2-~~~~]-4-~enzylox~-~-but-2-en-l-01(4) (19) tert-butanol(3 mL) was added over 3 h by syringe pump. The Diisobutyl aluminium hydride (21) (1.5 M solution in toluene, reaction mixture was cooled to room temperature, the layers Aldrich, 9.4 mL, 14.1 mmol) was added dropwise over 10 min were separated, and the aqueous layer was washed with methto a solution of 3 (1.25 g, 5.6 mmol) in methylene chloride (30 ylene chloride (3 x 5 mL). The combined organic extracts mL) at 0°C (cf. ref. 21). After stirring for 6 h, excess methanol were washed successively with 1 N NaOH solution, water, was added while the temperature was maintained between 0 and brine, dried over MgSO,, and concentrated to afford the and 5°C. The resulting white gelatinous precipitate was filcrude diol as a solid. Recrystallization from methylene chlotered through celite, washed with hot methanol, and the filtrate ride and hexanes affords 6 as white needles, mp 102-103°C was concentrated. Chromatography (20% ethyl acetate (470 mg, 52%). [alDZ0-22.2 (c 1.11, CH2C12)(lit. (12) [a1,2~ petroleum ether) on silica gel (230-400 mesh) gave 4 (1.0 g, of enantiomer: +40.3 (c 0.77, EtOH)). 'H NMR (200 MHz, 99%) as a colourless oil. 'H NMR (200 MHz, CDC1,) 6: 1.38 CDC1,) 6: 2.55-3.00 (m, 3H, ' 3 ~ H H ~ ~2(OH)), 6 ~ 5 ,3.293.36 (m, lH, CHHSC6H5),3.55-4.10 (m, 4H, 0-CH,, 2(0CH)), 4.53 (s, 2H, 0-CH2-C,H5), 7.14-7.39 (m, 10H, 2(C6H5)).',c NMR (50.3 MHz, CDCI,) 6: 135.0, 129.8 (2x), Literature references in this section refer to non-enriched (and in one case (19) singly enriched) compounds. 129.0 (2x), 128.5 (2x), 127.9 (2x), 127.8 (2x), 126.6, 73.6,
Can. J. Chern. Vol. 73, 1995
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71.9, 70.3 (d, J = 38.22 Hz), 38.0 (d, J = 38.22 Hz). MS (EI) d z : 306 (M', 15%), 167 (20), 124 (43), 91 (100). HRMS 2 0 ~ 3 found: ~ : 306.1208. calcd. for ' 3 ~ 2 ~ 1 5 ~306.1200;
mmol) dissolved in acetic anhydride (50 mL) and the mixture refluxed under nitrogen for 8 h. After cooling to room temperature, the reaction mixture was washed successively with saturated NaHCO, solution, water, and brine, dried (MgSO,), [4,4'-13~2]-(4~,5R)-5-Benzyloxymethyl-4-phenylthiomethyl-and concentrated. Chromatography (10% ether - hexanes) 2,2-dimethyl-1,3-dioxolane ([3,4-13~2]-(2~,3~)-2,3-~-isoafforded the oily product 9 (1.65 g, 73%) as a 5: 1 mixture of propylidene-1-benzyloxy-4-phenylthiobutane-2,3-diol, diastereo-mers. 'H NMR (200 MHz, CDC1,) 6: 1.32, 1.46, ([3,4-13~2]-(2~,3~)-2,3-~-isopropylidene-l -benzyl-41.48 (s, 6H, 2(CH3)), 1.90,2.06 (1:4.7) (s, 3H, COCH,), 3.52phenylthiobutan-1,2,3-triol) (7) (12) 3.80 (m, 2H, 0-CH,), 4.28 (dm, lH, J = 143.5 Hz, o-',cH), Diol6 (320 mg, 1.0 mmol) in methylene chloride (10 mL) was 4.37 (m, lH, 0-CH), 5.59 (m, 2H, 0-CH2C6H5),6.12 (dm, treated with 2,2-dimethoxypropane (250 FL, 2.2 mmol) and lH, J = 143.5 HZ, ',cH-s), 7.26-7.50 (m, 10 H, 2(C6H5)).13c phosphorus oxychloride (1 drop) was added. The solution was NMR (50.3 MHz, CDCI,) 6: 169.0, 137.5, 134.5, 133.5 (2x), stirred overnight at 22°C. 15% Aqueous NaOH solution (5 130.7, 128.2 (3x), 128.6, 128.5 (2x), 128.3 (2x), 128.1, 127.7, drops) was added and the mixture stirred for 30 min. After 127.5, 109.2, 81.9, 80.6, 79.6, 79.1, 78.2, 77.3, 76.8, 76.6, adding water, the layers were separated and the organic frac75.6,73.3,66.1,27.0,25.3,24.8,20.9. MS (EI) d z : 404 (M', tion dried and concentrated to afford 7 as a colourless oil (360 l%), 344 (4), 295 (3), 145 (53), 91 (100); (CI) d z : 422 (M' + mg, 99%). A small amount of the product was chromatoNH3, 18%), 354 (100). graphed (5% ether - petroleum ether) on silica gel (230 - 400 mesh) for analysis. Compound 7 slowly reverts to6 when kept in the refrigerator for several days. [alD20 -2.27 (c 1.01, [4,4'-13~2]-(4~,5R)-5-~enzyloxymethyl-4-jormyl-2,2CH2C12). 'H NMR (200 MHz, CDC1,) 6: 1.34 (s, 3H, CH,), dimethyl-1,3-dioxolane([1,2-'3~2]-4-0-benzyl-2,3-0-iso1.46 (s, 3H, CH,), 3.31 (dm, 2H, J = 77.5 Hz, ' 3 ~ ~ 2 - ~ - ~ 6 ~ 5 ) , propylidene-D-threose,[1,2-13~2]-(2~,3~)-4-0-benzyl-2, 3.53-3.64 (m,2H,O-CH2),4.31 (dm, lH, J = 150.4Hz. O0-isopropylidene-2,3,4-trihydroxybutanal [4,4'-13~2]',cH), 4.3 1 - 4.37 (m, lH, 0-CH), 4.56 (AB q, 2H, J = 12.0 (2S,3R)-5-(phenylmethoxy)methyl]-2,2-dimethyl-1,3Hz, 0-CH2C,H5), 7.17 - 7.37 (m, 10 H, 2(C6H5)).',c NMR dioxolane-4-carboxaldehyde) (10) (23) (50.3 MHz, CDCI,) 6: 137.6, 135.9, 129.4 (2x), 128.9 (2x), Potassium carbonate (1.30 g, 9.0 mmol) was added to a solu128.4 (2x), 127.8 (2x), 126.2 (2x), 108.8, 76.1, 75.7 (d, J = tion of 9 (1.50 g, 3.8 mmol) in methanol (50 mL) and the mix40.39), 73.6,68.4,39.9 (d, J=40.39), 28.0,25.4. MS (EI) d z : ture stirred overnight at 22°C. Under these conditions 346 (M', 7%), 199 (5), 167 (25), 109 (12), 91 (100). HRMS hydrolysis of the acetoxy phenylthio function is accompanied 2 4 ~13; 3 found: ~ : 346.1523. calcd. for ' 3 ~ 2 ~ 1 8 ~346.15 by inversion (13, 23). The solvent was removed in vacuo,
[4,4'-13~2]-(4~,5~)-5-~enzyloxymethyl-4-phen lthiomethyl2,2-dimethyl-1,3-dioxolane sulfoxide ([3,4-I C2]-(2R,3R)2,3-0-isopropylidene-1-benzyloxy-4-phenylthiobutane2,3-diol sulfoxide) (8)(12) m-Chloroperoxybenzoic acid (50-55%, 200 mg, ca. 0.58 mmol) dissolved in methylene chloride (6 mL) was added from a dropping funnel to 7 (200 mg, 0.58 mmol) in methylene chloride (6 mL) at -20°C. After stirring for 1 h, the mixture was washed with 1 N NaOH solution (2x), water (2x), and brine, dried (MgSO,), and concentrated to afford the oily product (206 mg, 99%) as a mixture of diastereomers.This product was used without further purification for the next step. When the preparation of the sulfoxide is carried out on a large scale (>1 g starting material) further oxidation takes place and a significant amount of the sulfone (>5%) is formed as a by-product. 'H NMR (200 MHz, CDCI,) 6: 1.29, 1.42, 1.43, 1.49 (s, 6H, 2(CH3)), 2.31 - 3.20 (m, 2H, ',cH,-s), 3.24 - 3.75 (m, 2H, 0-CH,), 4.18 - 4.61 (m, 3H, 0-13cH, 0-CH2C6H ), 4.93 5.12 (m, 1H.O-CH). 7.14-7.71 (m. 10H. 2(C6H5)."CNMR (50.3 MHz, CDCI,) 6: 137.7, 131.2, 131.1, 129.2 (2x), 129.0 (2x), 128.3 (2x), 128.2 (2x), 127.7 (2x), 124.6 (2x), 123.6, 108.7, 108.6,76.0,75.4,75.2,73.4,73.2,71.5 (d, J=39.9 Hz), 70.5 (d, J=40.0Hz), 68.2, 66.7, 66.1, 59.6(d, J=40.1 Hz), 57.6 (d, J = 40.0 Hz), 27.7, 25.2. MS (EI) d z : 363 (M' + 1, I%), 237 (16), 125 (52), 91 (100). HRMS calcd. for 1 3 ~ 2 ~ 1 8 ~ (M+ 2 5 + ~ 41): ~ 363.1550; found: 363.1533.
1
methylene chloride (15 mL) was added, and the mixture was washed with 0.5 N NaOH solution (2x) and brine. Drying (MgSO,) followed by concentration gave the crude aldehyde 10 (940 mg, 99%), which was used without further purification since it is reported (16) that the intensity of the CHO proton signal drops to one half after 12 h. 'H NMR (200 MHz, CDC1,) 6: 1.41 (s, 3H, CH,), 1.48 (s, 3H, CH,), 3.30-3.90 (m, 3H, o-',cH, 0-CH,), 4.15-4.32 (m, lH, 0-CH), 4.59 (s, 2H, CH2C6H5),7.28-7.34 (m, 5 H, C6H,), 9.73 (ddd, lH, J = 178.0 Hz, 26.0 Hz, 1.40 Hz, "COO).
[4,4'-13~2]-(4~,5R)-5-~enzyloxymethyl-4-(2'-(~~)hydroxyethyl-2,2-dimethyl-1,3-dioxolane ([2,3-13~2]-5-0benzyl-3,4-0-isopropylidene-1 -deoxy-D-xylitolplus [2,3-13~2]-5-0-benzyl-3,4-~-isopropylidene1-deoxy-Dlyxitol) (11) Grignard methylation of [1,2-'3~2]-4-0-benzyl-2,3-~-isopro pylidene-D-threose(10) and work-up was carried out, starting with 900 mg (3.6 mmol) 10 as describedfor the unlabeled compound (18 + 20). Yield 870 mg (91%). Ratio of diastereomers 2.5:l. 'H NMR (200 MHz, CDC1,) 6: 1.20 (m, 6H, 2(CH3)), 1.33, 1.34 (s, 3H, ' 3 ~ ~2.5:1), ~ ~2.80 3 (br , s, lH, OH), 3.2 1-3.72 (m, 3H, 0-CH,, 0-CH), 3.9 1-4.22 (m, 2H, 0 ',cH, ',cH-OH), 4.53 (s, 2H, CH2C6H5),7.26-7.29 (m, C6H5).13cNMR (50.3 MHz, CDC1,) 6: 137.7, 137.5, 128.4 (2x), 127.8 (2x), 127.6, 109.1, 109.0, 82.9 (d, J = 42.8), 82.3 [4,4'-13~2]-(4~,5~)-5-~enzyloxymethyl-4-(a-~~-a-acetoxy(d, J = 40.8), 81.9, 81.2, 73.6, 67.8 (d, J = 42.3), 67.5 (d, J = a-pheny1thio)methyl-2,2-dimethyl-1,3-dioxolane ([3,440.8), 27.1,26.9, 19.9, 19.7. MS (EI) d z : 268 (M', 0.5%),269 13~2]-(2~,3~)-2,3-0-isopropylidene-~ -benzyloxy-4(M++ H, 6), 253 (54), 210 (20), 91 (100); (CI) d z : 286 (M+ + phenylthio-4-acetoxybutane-2,3-diol) (9)(12) NH,, 30%), 268 (9). HRMS calcd. for ' 3 ~ 2 ~ , 3 ~ 2(M+ 3 ~+4H): Sodium acetate (2.70 g, 33 mmol) was added to 8 (2.10 g, 5.8 269.1663; found: 269.1664.
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Kennedy et al.
[2,3-13~2]-5-0-~enzyl-3,4-~-isopropylidene-l -deoxy-D-xyluReferences lose ( [4,4'-13~2]-(4~,5~)-4-acetyl-5-benzyloxymethyl-2,21. L. Slechta and L.E. Johnson. J. Antibiot. 29,685 (1976). dimethyl-1,3-dioxolane) (12) 2. H Hoekserna and L. Baczynskij. J. Antibiot. 29,688 (1976). Oxidation of 11and work-up was carried out, starting with 1.40 3. A. Yokota and K. Sasajirna. Agric. Biol. Chern. 48, 149 (1984). g (5.3 mmol) 11, as described for the unlabeled compound (20 4. A. Yokota and K. Sasajima. Agric. Biol. Chern. 50, 2517 -+ 22). Yield 1.30 g (93%). [alD20- 17.4 (c 1 SO, CH,Cl,). 'H (1986). NMR (200 MHz, CDC1,) 6: 1.41 (s, 3H, CH,), 1.45 (s, 3H, 5. M.L. Wolfrom and R.B. Bennett. J. Org. Chern. 30,458 (1965). CH3),2.24(d, 3H,J=4.0Hz, CH,'~CO),3.59-3.82(m, 3H, 0 6. A. Ishizu, K. Yoshida, and N. Yarnazaki. Carbohydr. Res. 23,23 (1972). CH,, o-',cH), 4.14-4.21 (m, lH, 0-CH), 4.58 (s, 2H, 7. S. David, B. Estramareix, J.-C. Fischer, and M. Therisod. J. CH2C6H5),7.29-7.32 (m, 5H, C6H5). I3cNMR (50.3 MHz, Chem. Soc. Perkin Trans. 1,2131 (1982). CDC13)6: 208.2 (d, J=45.9 Hz), 137.7, 128.2 (2x), 127.5 (2x), 8. R.E. Hill, B.G. Sayer, and I.D. Spenser. J. Am. Chem. Soc. 111, 110.9,81.7(d,J=45.9Hz),77.0,73.4,70.1,26.8,26.1(2x). 1916 (1989). MS (EI) d z : 266 (MC,3%), 222 (1 I), 91 (100); (CI) d z : 284 9. T. Shono, Y. Matsumura, H. Harnaguchi, and S. Naitoh. J. Org. (MC+ NH,, 94%), 267 (MC+ H, 70), 209 (100). HRMS calcd. Chern. 48,5 126 (1983). 2 0 ~ 4 :found: 266.1425. for ' 3 ~ 2 ~ 1 3 ~266.1428; 10. R.E. Hill, B.G. Sayer, and I.D. Spenser. J. Chem. Soc. Chern. Comrnun. 612 (1986). 11. J. Wolinsky and K.L. Erickson. J. Org. Chem. 30,2208 (1965). 12. T. Katsuki, A.W.M. Lee, P. Ma, V.S. Martin, S. Masarnune, K.B. Sharpless, D. Tuddenham, and F.J. Walker. J. Org. Chern. 47, 1373 (1982). 13. S.Y. KO, A.W.M. Lee, S. Masamune, L.A. Reed 111, K.B. Sharpless, and F.J. Walker. Tetrahedron, 46,245 (1990). 14. E. Hungerbuhler and D. Seebach. Helv. Chim. Acta, 64, 687 (1981). 15. T. Mukaiyarna, K. Suzuki, and T. Yamada. Chem. Lett. 929 (1982). 16. T. Mukaiyama, K. Suzuki, T. Yamada, and F. Tabusa. Tetrahedron, 46,265 (1990) 17. G. Solladie, C. Frechou, J. Hutt, and G. Dernailly. Bull. Soc. Chirn. Fr. 827 (1987). 18. G. Solladie, J. Hutt, and C. Frechou. Tetrahedron Lett. 28, 61 (1987). [2,3-'"~,]-1 - ~ e o x y - ~ - x ~ ~(14) u~ose 19. Y. Yabe, D. Guillaume, and D.H. Rich. J. Am. Chern. Soc. 110, Hydrogenolysis of the benzyl ether 13 (300 mg, 1.3 mmol) in 4043 (1988). the presence of 10% palladiurnlcarbon, as described for the 20. J. Villieras, M. Rambaud, and M. Graff. Tetrahedron Lett. 26, unlabeled compound (24 -+ 27), gave [2,3-'3~2]-1-deoxy-~53 (1985). xylulose (14) in quantitative yield (180 mg) as a colourless oil. 21. E. Winterfeldt. Synthesis, 617 (1975). 'H NMR (200 MHz, CD30D) 6: 1.23-1.37 (m, 3H, CH,'~C22. K.C. Nicolaou, R.A. Daines, J. Uenishi, W.S. Li, D.P. Papahatjis, OH), 2.16 (dd, 3H, J = 6.1 Hz, 4.9 Hz, CH,'~CO)(cH,',candT.K. Chakraborty. J. Am. Chern. Soc. 110,4672(1988). OH:'~COCH - 2.1: l), 3.15-3.23 (m, 2H, 2(OH)), 3.24-4.6 23. A.W.M. Lee, V.S. Martin, S. Masamune, K.B. Sharpless, and - 0-CH ,OH). 'H NMR (200 MHz, D,O) 6: F.J. Walker. J. Am. Chern. Soc. 104,3515 (1982). (m, 5 H, CH-I,CH, 24. E.J. Corey and G. Schmidt. Tetrahedron Lett. 399 (1979). 1.30-1.34 m, 3H, CH,'C-OH). 2.17 (d. J = 4.66 Hz, 25. H. Iida, N. Yarnazaki, and Ch. Kibayashi. J. Org. Chem. 52, CH,'~CO)(CH,'~C-OH:CH,'~CO= 1:1.5), 3.40-4.41 (m, 4H, 3337 (1987). 0-CH,, ',cH-CH). I3cNMR (50.3 MHz, CD30D) 6: 212.2 26. A.J. Mancuso, S.-L. Huang, and D. Swem. J. Org. Chern. 43, (d, J=41.4Hz), 110.6(d, J=49.5Hz), 105.8(d,J=46.4Hz), 2480 (1978). 85.1 (d, J = 47.0 Hz), 83.6 (d, J = 48.9 Hz), 78.4 (d, J = 41.4 27. D.R. Williams, D.L. Brown, and J.W. Benbow. J. Am. Chern. Hz), 77.6, 72.6, 71.2, 19.1, 16.8, 16.6. I3cNMR (50.3 MHz, SOC.111, 1923 (1989). D20)6:213.1 (d,J=40.6Hz), 109.4(d,J=48.5Hz) 105.5(d, 28. T.J. Tewson and M.J. Welch. J. Org. Chem. 43, 1090 (1978). J=47.1Hz),82.7(d,J=46.9Hz),81.3(d,J=46.5Hz),77.2 29. C.C. Wei, S. De Bemardo, J.P. Tengi, J. Borgese, and M. (d, J=41.2Hz), 78.3,72.8,71.8, 16.9, 14.8. MS (C1)dz: 154 Weigele. J. Org. Chem. 50, 3462 (1985). 30. C.H. Heathcock and R. Ratcliffe. J. Am. Chem. Soc. 93, 1746 (MC+ NH,, 90%), 136 (M', loo), 119 (70), 101 (36). (1971). 31. J.S. Bindra and A. Grodski. J. Org. Chem. 43,3240 (1978). Acknowledgment 32. G. Sheldrick. SHELXTL, v.5. Crystallographic software package. Siemens Industrial Automation, Inc., Madison, Wis. 1994. This investigation was supported by a research grant 33. A.J.C. Wilson (Editor). International tables for crystallography. (GM50778) (to 1.D.S) from the National Institute of General Vol. C. Kluwer Academic Publishers, Dordrecht. 1992. Table Medical Sciences, U.S. Public Health Service, which is grate6.1.1.4. fully acknowledged. 34. A.J.C. Wilson (Editor). International tables for crystallography. Vol. C. Kluwer Academic Publishers, Dordrecht. 1992. Table 4.2.6.8.
[2,3-'3~2]-5-~-~enzyl-~-deoxy-~-xy~u~ose (13) Hydrolysis of 5-0-benzyl-3,4-0-isopropylidene-1-deoxy-Dxylulose (12) (600 mg, 2.3 mmol) and work-up was canied out as described for the unlabeled compound (22 -+ 24). Yield 460 mg (90%). [alD2050.43 (c 1.25, CH,Cl,). 'H NMR (200 MHz, CDC1,) 6: 2.23 (dd, 3H, J =6.04 Hz, 1.27 Hz, CH,'~CO),2.8 (br s, lH, OH), 3.39 (s, lH, OH), 3.57-3.60 (m, 2H, 0-CH,), 3.784.22 (m, 2H, o-',cH, 0-CH), 4.53 (s, 2H, CH2C6H5),7.247.37 (m, 5 H, C6H5).',c NMR (50.3 MHz, CDC1,) 6: 208.1 (d, J=39.1 Hz), 137.4, 128.2(2~),127.6(3~),77(d, J=39.4Hz), 73.3,70.7,70.5,25.5. MS (EI) d z : 227 (MC+ H, 2%), 226 (MC, 0.5), 136 (5), 91 (100); (CI) d z : 244 (MC+ NH,, 100). HRMS l , ~+4H): 227.1 194; found: 227.1 192. calcd. for ' 3 ~ 2 ~ l o ~ (M'
