New N-Acylating Reagents Derived from 3-Deoxy-l-glycero-tetronic Acid¹

Abstract

Commercially available N-Boc-4-O-benzyl-l-homoserine was treated with trifluoroacetic acid and the corresponding, N-deprotected derivative was submitted to deamination to give 4-O-benzyl-3-deoxy-l-glycero-tetronic acid (5). In another approach to 3-deoxy-l-glycero-tetronic acid protected at position 4, the carboxylic groups in L-malic acid were reduced, and the resulting triol was benzylidenated. Oxidation of the 2,4-O-benzylidene derivative formed with CrO₃-pyridine complex in the presence of t-butyl alcohol gave t-butyl 2,4-O-benzylidene-3-deoxy-l-glycero-tetronate (13). The latter was saponified with aqueous sodium hydroxide to give, after Na⁺ exchange for H⁺, 2,4-O-benzylidene-3-deoxy-l-glycero-tetronic acid (15). Opening of the acetal ring in 13, followed by hydrolytic cleavage of the t-butyl ester function gave material indistinguishable from 5 obtained in the original way. When tested for their efficiency of N-acylation of derivatives of D-perosamine, both acids 5 and 15 gave the corresponding tetronamido derivatives in high yields.

Notes

Synthesis of ligands related to the Vibrio cholerae O-specific antigen. Part 10. For Part 9, see ref. 15.

On leave from Fuji Chemical Industries, Ltd., 530 Chokeiji, Takaoka, Toyama 933, Japan.