Pseudo cord factors: derivatives of alpha-D-glucopyranuronosyl (1-1) alpha-D-glucopyranuronoside

We describe the synthesis of 6 pseudo cord factors (psi CF), analogs of the natural trehalose-6,6'-dimycolate, but based instead upon the dicarboxylic acid (TDA) that is obtained from trehalose by Pt-catalyzed oxidation. From TDA, several bis-amides ('mirror amide' psi CF) and a diester ('mirror' psi CF) of intermediate to high molecular weight were prepared. These superficially resemble cord facotr, have similar infared spectra and, like the natural product, several have impressive toxicity in mice and tumor-regression activity; but the latter property does not depend upon the former. A curious abrogation of biological activities results from introduction of a hexamethylene diamine 'spacer' between the carbohydrate core and the lipid substituents. The results suggest that (excepting the 'spacer' effect) the type of covalent linkage between the carbohydrate and lipid moieties may be relatively unimportant for expression of some of the biological activities of cord-factor-like glycolipids.