D-arabinose derivatives

Fig. 4 Comparison of the relevant stereogenic centers in the d-arabinose derivative 121 and in preussin (2)...

The enantiomorph, also a syrup, was synthesized from 3,6-anhydro-4,5-O-isopropylidene-D-mannitol18 by periodate oxidation to the corresponding D-arabinose derivative, followed by reduction in the presence of Raney nickel.17 2,5-Anhydro-D-xylitol, 2,5-anhydro-D-ribitol, and 2,5-anhydro-D-lyxitol (1,4-anhydro-D-arabinitol)19,20 were... 

To a mixture of glucopyranose (0.22 mmol) in dry cyclohexane (24 ml) under an argon atmosphere were added iodosylbenzene (0.43 mmol) and iodine (0.22 mmol) at room temperature. The mixture was stirred for 20 h at the same temperature. After the reaction, the reaction mixture was poured into water and extracted with ether. The organic layer was washed with aq. sodium thiosulfate solution, water, and dried over Na2S04. After removal of the solvent, the residue was chromatographed on silica gel (eluent hexane/ethyl acetate = 65/35) to give D-arabinose derivative in 86% yield [68]. 

During the same study, the Italian researchers aiming at the synthesis of carbaoctanose compounds (vide infra), synthesized a nine-carbon long intermediate 308 which served both to access the octanose and the septanose targets. As shown in Scheme 50, the route to 308 entailed vinylogous aldol coupling between pyrrole 76 and D-arabinose derived aldehyde 306 producing lactam 307, the immediate precursor of 308. To... 

D-Arabinose derivatives Bis(metby] 3,4-0-i opropylidene- 8 D-arabinopyranoside) 2,2 -tbionooar-bonate 210-211 -254 C H, J, K 31... 

Horton et al. were interested in the synthesis of tetra-C-substituted carbocycles, and extensively studied asymmetric Diels-Alder reactions employing acyclic unsaturated carbohydrate derivatives. Thus, the thermal cycloaddition of the D-arabinose-derived c/i-dienophile (Z)-100 with cyclopentadiene gave endo-adduct 101 in excellent optical purity. The high diastereo-facial differentiation in this reaction arises from a highly favored conformation at the allylic center [76,77] (Scheme 10.33). Therefore, conformer 102 seems to be more favored than 103, where the latter suffers from severe allylic strain between the methoxycarbonyl and the C4-acetoxy group... 

The two-carbon chain elongation of protected D-glyceraldehyde (R)-24 and (R)-62 can be realized via ( -7-alkoxyallylboronate additions, followed by alkene ozonolysis. The allylboronate 162 generated in situ adds to (R)-62 giving a single stereoisomer 163, which can be converted to D-arabinose derivatives following ozonolysis (Scheme 13.57). Similarly, 164 added to (R)-24 gave a major adduct 165 that was then converted into 2-0-methyl-D-arabinose derivatives [105]. 

The plant-growth-regulating benzimidazol-2-yl acyclo C-nucleoside 116 was prepared (93ZOR1643) by eyclocondensation of the aldehydro-D-arabinose derivative 113 and the quinonimine 114 (Scheme 35). 

Hanessian reported that, on treatment with sodium azide in N,N-dimethylformamide, the open-chain D-arabinose derivative (261) yields the L-xylose derivative (263) mainly, accompanied by a small proportion of a compound that was assigned the n-arabinose structure (264) on the basis of infrared and optical rotation data. The azidonium ion intermediate... 

The core structure 63 of azinomycins A and B has been synthesized from the 1,1-bis(ethylthio)-4,6-isopropylidene D-arabinose derivative 54 by treatment with p-methoxy-benzyl chloride, followed by removal of the dithioacetal groups with N -bromosuccinimide and subsequent reduction of the resulting aldehyde to afford 55 (Schemes 7 and... 

Synthesis from o-arabinose Two researcher groups" " have synthesized the intermediate 20 from D-arabinose (Scheme 4). The D-arabinose derivative 25 was benzoylated and hydrogenated to give the corresponding hemiacetal, which was then subjected to Wittig reaction to give 26 and 27. Reduction of 26 followed by debenzoylation led to the diol... 

Following this strategy, a straightforward approach was developed to d-arabinose-derived methylenebisphosphonate 76 in which one phosphorus atom belongs to the 1,2-phospholane moiety (Scheme 43) [95], This compound was designed as a possible transition state inhibitor of mycobacterial arabinosyltransferases, known to play a crucial role in the biosynthesis of arabinan part of the mycobacterial cell wall. 

Much effort towards stereoselective synthesis of 3-deoxy-2-ulosonic acids resulted in the development of several strategies based on the diverse building units. Among them aldol reaction between D-arabinose derivative 50 and methyl dichloroacetate (51) deserves some attention [78] (Scheme 14). The condensation product isolated as oxirane derivative 52 reacted smoothly with Mgk to give the intermediate 53, easily convertible into 3-deoxy-D-ara6mo-2-heptulosonic acid methyl ester 56 in high yield. 

Tetra-0-benzoyl-/3-L-arabinopyranose (enantiomorph of 165b) is isomerized by hydrogen fluoride after 64 hours, to give 36% of 2,4-di-0-benzoyl-/3-L-ribopyranosyl fluoride (enantiomorph of 167). This reaction with D-arabinose derivatives has been examined by n.m.r. spectroscopy. Tetra-O-acetyl-a-D-arabinopyranose (165a)... 

Fused triazoles such as the D-arabinose-derived 112 were synthesized by intramolecular condensation of the 7-azide produced by displacement of the 7-tosylate from unsaturated ester 111 (Scheme 15)/ Triazole 114 was synthesized by intramolecular dipolar cycloaddition of the azido-alkyne 113, derived by... 

Bicyclic isoxazolidine 63 was obtained in good yield by 1,3-DC of D-arabinose-derived nitrone 61 and D-mannitol-derived alkene 62 and then used as common intermediate for a divergent synthesis of polyhydroxy-indolizidines and -pyrrolizidines. Iminosugars 64 and 65 proved to be good inhibitors of some commercially available glycosidases (14JOC10786). 

A very high degree of asymmetric induction was evident in the thermal reaction of the D-arabinose-derived cis-dienophile 20 with cyclopentadiene, and the crystalline adduct isolated in 95% yield was identified as methyl (5R,6S)-6-endo-(1,2,3,4-tetra-O-acetvl-D-arabino-tetritol-l-yl)bicyclo[2,2.1]hept-2-eno-5-endp-carboxylate (31), mp 103 by NMR spectroscopy and also by X-ray crystallography. Use of the same sequence starting from L-arabinose gave the enantiomer (32) of 31. 

The triene 41 (9 1 mixture of Z and E isomers) has been prepared from the D-arabinose derivative 39 (32) in three steps. 40 has been obtained in a Wittig reaction. Oxidation of the terminal hydroxyl group and another chain extension led to 41 (Figure 13.). IMDA reaction of the latter at 120 gave the c s-fused product 42 together with trace amounts of an unidentified compound. 

Branched-chain Sugars. - The silicon-tethered radical cyclisation adduct 14, 2 l-< -acetyl-2,4 5,6-di-0-isopropylidine-l-C-phenyl-D-g(ycgro-D-idc>-hexitol, the butyrolactones 15 and 16, the D-arabinose derived 17, 5 the diastereomerically pure disaccharide 18 and the a- and P-5 -phenyl analogues of daunomycin 19 and the C-linked disaccharide 20. ... 

Reaction of imines of type (102) with the TMS-ketene acetal derived from methyl isobutyrate, followed by hydrolysis, gave p-aminoacids (105) with high e.e. 9 The stereoselective Ugi synthesis of a-aminoacids using D-galactos-ylamine auxiliaries (Vol. 22, p, 110-111) has been employed using the D-arabinopyranosylamine derivative (106) since the D-arabinose derivative is enantiomeric with a D-galactose system, except for loss of C-6, the a-aminoacids are now produced with (S)-chirality. 

D-Arabinose has been converted to the aldehyde 316, used in synthesis of the eicosatetraenoic acid (leukotriene) 12-oxo-LTB4 The D-arabinose-derived dithioacetal 317 has been used to construct 319, which is related to the C12-C18... 

---