Trideoxy sugars synthesis

A. H. Haines, The synthesis of trideoxy sugars. A preparation of rhodinose (2,3,6-trideoxy-a-L-t/ireo-hexose) and methyl 2,3,6-trideoxy-a-L-eryr/u-o-hexopyranoside, Carbohydr. Res., 21 (1972) 99-109. 

Ethoxy-3,4-dihydro-6-methyl-2ff-pyran (179) has been used78 as the substrate for the synthesis of methyl 2,3,6-trideoxy-a-DL-enjthro-hex-2-enopyranoside (180). The synthesis consisted in hydroboration of the double bond, followed by oxidation, bromination at C-2, and elimination of HBr, to give 180. This compound was, in turn, converted into methyl DL-mycaminoside,7K DL-oleandroside,79 and other sugar glycosides (see Section III,2). 

A similar approach, involving condensation of 4-nitro-2-butanol with sodium glyoxylate309 in the presence of sodium hydrogencarbon-ate offers a route to 3-amino-3,4,6-trideoxy-DL-hexopyranoses. Two lactones, 552 and 553, were formed during the reaction (overall yield, 42%) in the ratio of 3 1 these lactones may be considered to be potential precursors of a variety of isomeric 3-amino sugars. The synthesis... 

The addition reaction to branched glycoenopyranosides sometimes offers a stereospecific pathway to A-type, branched sugars. A stereospecific synthesis of the e valose (15) derivative (110) by cis-hy droxy lation of methyl 4-0-benzoyl-2,3,6-trideoxy-3-C-methyl-a-D-en/thro-hex-2-en-opyranoside (109), derived from 57a (R = Me), with osmium tetraoxide... 

The synthesis of a member of this class of deoxy sugars was accomplished in 1950. The then well-known ethyl 2,3-dideoxy-a-D-en/l/iro-hex-2-enopyranoside was reduced and the product was converted into ethyl 2,3,0-trideoxy-4-O- (methylsulfonyl) -a-D-eryfAro-hexopyranoside by way of the 4,6-dimethanesulfonate. During this work, it was found that, when the dimethanesulfonate of the unsaturated derivative is treated with sodium iodide in the cold, a selective displacement at C-4 occurs, no doubt due to the activated allylic system. The resulting 4-iodo derivative could... 

Anthracyclines isolated from stieptomyces show a 2,3,6-trideoxy-3-amino-L-/yxo-configurated sugar oc-attached to the aglycon. Therefore, the first interest centered on the synthesis of aminodeoxy sugars in the l-lyxo series, e.g., daunosamine [46-50]. Several new glycosides were prepared [51] in order to evaluate structure-activity relationships. 

For an alternate route to this compound see Chapleur, Y, Germain, F, Aubry, A, Bayeul, D, Elimination reactions of 2-C-methyl-2-deoxy sugars application to the synthesis of methyl 2,3, 4-trideoxy-2,4-di-C-methyl-6-0-triphenylmethyl-D-/yxo-/iexo-pyranojiiie and its X-ray crystal structure, 7. Carbohydr. Chem., 3, 443-459, 1984. 

Oxidation of alcohol 100 to aldehyde 103 with PCC followed by treatment of the unpurified aldehyde with (carbethoxyethylidene)triphenylphosphorane affords a poor yield of a mixture of diastereomeric olefins 104 together with substantial amounts of unreacted 100. This may suggest that PCC oxidation is not the preferred method for optimal oxidation of 100 to 103. Nevertheless, the diastereomeric mixture 104 has been exploited in the synthesis of A -ben-zoyl-2,3,6-trideoxy-3-amino-L-x> /o-hexapyranose (105) [42]. In three steps, 105 is converted to AAbenzoyl-L-ristosamine (106), the aminodeoxy sugar component of the antibiotic risto-mycin [43] (Scheme 24). 

J. Yoshimura, M. Ywakawa, and Y. Ogura, Amino sugars. XXV. Synthesis of benzyl 2-acetamido-3-amino-2,3,4-trideoxy-a-D-arah/no-hexopyranoside, Bull. Chem. Soc. Jpn., 49 (1976) 2506-2510. 

Treatment of the D-arabino- and D-xylo-furanosides 1 and 2 with DAST afforded the deoxyfluoro derivatives 3 and 4 in the former case, whereas the latter gave the anhydro-sugar 5 and the deoxyfluoro compound 6 (Scheme 1). Osmium tetroxide-catalysed dihydroxylation of the chiral unsaturated derivative 7 led to the synthesis of 2-deoxy-2-fluoro-D-xylose and -L-lyxose." 1,2,5-Tri-deoxy-2-fluoro-1,5-imino-D-glucitol and 1,2,5-trideoxy-1 -fluoro-2,5-imino-D-... 

The new antitumour antibiotic pyrrolosporin A (11) is a macrolide with an unusual spiro-a-acyl tetronic acid moiety. It also contains a 4-amino-2,4,6-trideoxy-P-D-aru6mo-hexopyranose unit, a sugar not previously found in nature (see Vol. 24, p. 148-9 for the synthesis of this sugar in studies of antibiotic analogues), and methanolysis of pyrrolosporin A gave the methyl a-pyranoside, with the pyrrole unit still linked to the sugar. 

There has been a continuing interest in syntheses of 3-amino-2,3,6-trideoxy-hexoses such as daunosamine (9), acosamine (10), etc. In an interesting paper by Fronza et the two sugars have been synthesized from the non-carbohydrate compound (11), which was obtained in 25-30% yield from the incubation of cinnamaldehyde v th acetaldehyde in the presence of bakers yeast (Scheme 2). The crucial amino-lactone (12) was also synthesized from L-threonine. The same authors have also completed their synthesis of A-benzoyl-L-ristosamine (3-benzamido-2,3,6-trideoxy-L /6o-hexose) from 3-benzamido-2,3,6-trideoxy-L-xy/o-hexono-1,5-lactone (Vol. 13, p. 79). An alternative synthesis of methyl A-acetyl-a-L-acosaminide (13) has been described by reduction of the appropriate acetylated oxime by diborane. The thioglycoside (14) was also prepared. ... 

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