Synthesis of alkyl and cycloalkyl α-d-mannopyranosides and derivatives thereof and their evaluation in the mycobacterial mannosyltransferase assay

The synthesis of a series of alkyl (having from C6 to C20 aglycones), cyclohexyl, and cyclohexylalkyl α-d-mannopyranosides, 6-deoxygenated analogs, thioglycosides, and sulfones derived thereof, is reported. Here, under the in vitro assay conditions used, none of the 15 tested compounds acted as an inhibitor of the mannose transfer catalyzed by the enzymes present in mycobacterial membrane and cell wall fractions. Mannopyranosides comprising shorter aliphatic, up to 8 carbon atoms long linear, or cyclic aglycone served as the acceptor substrates in the mycobacterial mannosyltransferase reaction. The thioglycosides exhibited similar behavior, in contrast to the sulfones, which were essentially not recognized by the mycobacterial enzymes. 6-Deoxygenated glycosides were not processed by the enzymes, suggesting that the mannose transfer occurs at position 6 of the acceptors.

Graphical abstractThe synthesis of a series of alkyl and cycloalkyl α-d-mannopyranosides, their 6-deoxygenated analogs, thioglycosides, and sulfones derived thereof and their evaluation in the mycobacterial mannosyltransferase assay are reported.Figure optionsDownload full-size imageDownload as PowerPoint slide