Conjugates of plumbagin and phenyl-2-amino-1-thioglucoside inhibit MshB, a deacetylase involved in the biosynthesis of mycothiol.

N-Acetylglucosaminylinositol (GlcNAc-Ins)-deacetylase (MshB) and mycothiol-S-conjugate amidase (Mca), structurally related amidases present in mycobacteria and other Actinomycetes, are involved in the biosynthesis of mycothiol and in the detoxification of xenobiotics as their mycothiol-S-conjugates, respectively. With substrate analogs of GlcNAc-Ins, MshB showed a marked preference for inositol as the aglycon present in GlcNAc-Ins. The inhibition of MshB and Mca by 10 thioglycosides, 7 cyclohexyl-2-deoxy-2-C-alkylglucosides, and 4 redox cyclers was evaluated. The latter contained plumbagin tethered via 2 to 5 methylene carbons and an amide linkage to phenyl-2-deoxy-2-amino-1-thio-alpha-d-glucopyranoside. These proved to be the most potent amongst the 21 compounds tested as inhibitors of MshB. Their inhibitory potency varied with the length of the spacer, with the compound with longest spacer being the most effective.

Extending the scope of the Ferrier reaction: fragmentation-rearrangement reactions of selectively substituted 1,2-cyclopropanated glucose derivatives.

Two further variations of the Ferrier-type allylic rearrangements of 1,2-cyclopropanated glucose derivatives bearing an acetoxylated carbon at the 1'-position are described. In the first, treatment of the cyclopropanated sugar with a nucleophile (ROH, PhSH, azide) and Lewis acid (BF(3)·Et(2)O or Al(OTf)(3)), gives 2-C-vinyl glucosides in good yields and α-selectivities. Alternatively, treatment with a combination of Lewis acid and acetic acid leads to a novel fragmentation-rearrangement to form a 2,3-dehydro-2-formyl-C-glycoside.