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M L Wolfrom

Publications and source records attributed to M L Wolfrom.

At least 19 recordsLinked to original sources
PubMed1975

Synthesis and spectral properties of cytosine nucleosides of 2-amino-2-deoxy-alpha-D-arabino-furanose and -pyranose.

Ethyl 2-deoxy-3,5-di-O-p-nitrobenzoyl-1-thio-2-(trifluoroacetamido)-beta-D-arabinofuranoside (3) was converted into the glycosyl chloride. Condensation of the latter with 2,4-dimethoxypyrimidine, followed by amination, gave 1-(2-amino-2-deoxy-alpha-D-arabinofuranosyl)cytosine (6), which was also obtained from the alpha-D anomer (4) of 3. Similarly, 1-(2-amino-2-deoxy-alpha-D-arabinopyranosyl)cytosine (12) was synthesized from ethyl 2-deoxy-3,4-di-O-p-nitrobenzoyl-1-thio-2-(trifluoroacetamido)-alpha-D-arabinopyranoside (9). The p.m.r. spectra of these nucleosides, as well as those of the 1-thioglycosides, are discussed in terms of the conformation of the sugar portion. In particular, a large change of the J1,2 coupling constants of the alpha-D-furanosides, according to the substituents at C-1 and C-2, was interpreted on the basis of conformational mobility.

Arabinose↗
PubMed1975

Synthesis of a cytosine nucleoside of 2-amino-2-deoxy-beta-D-xylofuranose.

1-(2-Amino-2-deoxy-beta-D-xylofuranosyl)cytosine (13) was synthesized by three routes: (a) coupling of 2-deoxy-3,5-di-O-p-nitrobenzoyl-2-(trifluoroacetamido)-D-xylofuranosyl chloride (5) with 2,4-dimethoxypyrimidine and subsequent treatment with methanolic ammonia, (b) coupling of 5 with 4-N-acetyl-2-O,4-N-bis(trimethylsilyl)cytosine followed by treatment with methanolic ammonia, and (c) thiation of 1-[3,5-di-O-acetyl-2-deoxy-2-(trifluoroacetamido)-beta-D-xylofuranosyl]uracil (6) by treatment with phosphorus pentasulfide in pyridine followed by amination of the resulting 4-thionucleoside 12 with metanolic ammonia. The best yield was obtained via route (a).

Chromatography, Ion Exchange↗
PubMed1975

Four isomeric ethyl 1-thioglycosides from 2-amino-2-deoxy-D-arabinose.

Ethyl 2-amino-2-deoxy-1-thio-alpha- and -beta-D-arabinopyranoside (2 and 4) were obtained by direct ethanethiolation of 2-amino-2-deoxy-D-arabinose (1), and their structures were determined by mass and p.m.r. spectrometry. Ethyl 2-amino-2-deoxy-1-thio-alpha- and -beta-D-arabinofuranoside (11 and 13) were prepared by partial demercaptalation of 2-amino-2-deoxy-D-arabinose diethyl dithioacetal (6) with mercuric chloride (or, preferably, with bromine), with or without protection of the 5-hydroxyl group. Demercaptalation with mercuric chloride gave the beta-D anomers almost exclusively, and treatment with bromine gave a mixture of the alpha and beta anomer in the ratio of similar to 1:1. Alternatively, direct ethanethiolation of 1 in trifluoracetic acid yielded the alpha-D anomer. The structures of 11 and 13 were determined by mass spectrometry, by direct comparison of their N-acetyl derivatives with an authentic enantiomorph (15b), and by p.m.r. spectroscopy. The physicochemical properties of the four 1-thioglycosides (2,4,11, and 13) were compared with those of the O-GLYCOSIDES of D-arabinose.

Amino Sugars↗