Amino acid, acetylated, epoxide

Acids forming amides and an epoxide—derived, acetylated amino acid. 

The 4-amino group of 31 was selectively acetylated under acidic conditions using acetic anhydride (1 equiv.) and methanesulfonic acid (1 equiv.) in acetic acid and f-butylmethyl ether to give 32. Deallylation of 32 using 10% Pd/C in the presence of ethanolamine in refluxing ethanol proceeded as before to afford 1, which was converted to the phosphate salt in 70% yield with high purity (99.7%). The overall yield of 1 from epoxide 23 was 35-38%. 

Acetyl hypofluorite (AcOF) and methyl hypofluorite (MeOF) as fluorinating agents of olefins and aromatics3 HOF-MeCN an oxygen transfer agent in epoxidation of electron poor olefins, in Baeyer-Villiger reaction, in oxidation of a-amino acids to a-nitro acids. 

It is known that deamination of some readily available amino acids can be performed with nearly quantitative retention of configuration. Based on this conversion, Yamada and co-workers elaborated an ingenious synthesis of o-ribose and D-lyxose starting from L-glutamic acid. The preliminary communication of this work was reported in the first volume of Ais series.Now the full details have been published. In an extension of the application of the unsaturated intermediate (399) for the synthesis of other pentoses, all 2,3-anhydro derivatives (400-403) were prepared. LAH-Reduction of -D-ribo and o-D-lyxo epoxides (400 and 401) afforded, after acetylation, 3-deoxy-pentosides 404 and 405, whereas the same reaction conditions converted fi-D-lyxo a-D-ribo epoxides (402 and 403) into the corresponding 2-deoxy-derivatives (406 and 407). 

Diaxial amino-alcohols have been prepared efl5ciently by treating epoxides (e.g. 83) with acetonitrile and an acidic catalyst (either perchloric acid or boron trifluoride ). Hydrolysis of the ion (84) gives the IV-acetyl-derivative (85) of the amino-alcohol. 

The reaction of the methyl ester of the racemic epoxide 101 with acetone and aluminum chloride gave a 4,S-0-isopropylidene derivative 108. Michael addition of ammonia to the conjugated double bond of 108 with concomitant ammonolysis of the ester group afforded a mixture of 3-amino-2,3,6-trideoxy-4,5-0-isopro-pylidene-OL-arabino- and -r/Z o-hexonamides (109). For the purpose of isolation the mixture was N-acetylated. Acidic hydrolysis of the amide groupings gave a mixture of y- and 8-aminolactone hydrochlorides (110 and 111). Careful N-acetylation and reduction of the lactone carbonyl groups in 112 and 113 afforded N-acetyl-DL-acosamine (115) in 36% yield. The stereoisomeric potential partner of 115, N-acetyl-DL-ristosamine (116), was not isolated in this procedure. 

In this case, it doesn t matter which azide you start with triphenylphosphine converts them both to the same aziridine. Like epoxides, aziridines open with nucleophiles under acid catalysis, and azide is used again to put in the second amino group by attack at the less hindered end of the aziridine. To get the right amino group acetylated, the amide is formed before the azide is reduced, this time with tributylphosphine. The drug is formulated as a stable phosphate salt by treatment with phosphoric acid. 

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