THE SYNTHESIS OF CHIRAL COMPOUNDS OF BIOLOGICAL AND SYNTHETIC INTEREST USING ANHYDRIDE OF L-TARTARIC ACID

Abstract

Chiral protected and deprotected amides were synthesized by using commercially available L-tartaric acid having two asymmetric centers and C2 axis of symmetry. In the synthetic sequence, diacid functionality of L-tartaric acid was protected as dimethyl ester and diol as 1,3-dioxolane. The partial hydrolysis of 1,3-dioxolane dimethyl ester gave the corresponding monoester. Monoester upon treatment with different substituted anilines gave desired amides (2a-2t). Amides (2a-2t) afforded compounds (3a-3t) with the aid of acetyl chloride in methanol. All the compounds were characterized by using sophisticated spectroscopic techniques including IR, 1H NMR, 13C NMR, EI-MS and elemental analysis. The structures of compounds 2g, 2r and 3i were also unambiguously confirmed by X-ray crystallography. Protected (2a-2l) and deprotected amides (3a-3l) were tested for their antimicrobial activities at different concentrations against different fungal and bacterial strains and were found effective. Monoaryl esters of L-tartaric acid (4a-4h) were prepared and processed further in Fries rearrangement. The structure of compound 4e in the series was also confirmed by X-ray crystallography. N-Linked glycopyranosides (10a-10e) and O-Linked glycopyranosides (11a-11e) were synthesized from monoester of L-tartaric acid. The synthesized compounds were confirmed with the aid of spectroscopic techniques. The structure of compound 11c in the series was supported by X-ray analysis. Antileishmanial activity of the glycopyranosyl amides (10a-10e) and glycopyranosides (11a-11e) was assayed which showed moderate to good activities. Synthesis of glycoconjugates (13a-13e) was carried out by using glycopyranosyl α-trichloroacetimidates and dimethyl-L-tartrate. Chiral imides and amides were prepared from diacetyl-L-tartaric acid anhydride and aliphatic, substituted aromatic amines and amino acids. The imides (14g-14m) were subjected for their antifungal and antibacterial activities against different fungal and bacterial strains. All the compounds showed good antifungal and moderate to good antibacterial activities.