Glucopyranosylidene-spiro-benzo[ b][1,4]oxazinones and -benzo[ b][1,4]thiazinones: Synthesis and Investigation of Their Effects on Glycogen Phosphorylase and Plant Growth Inhibition.

Glucopyranosylidene-spiro-benzo[ b][1,4]oxazinones were obtained via the corresponding 2-nitrophenyl glycosides obtained by two methods: (a) AgOTf-promoted glycosylation of 2-nitrophenol derivatives by O-perbenzoylated methyl (α-d-gluculopyranosyl bromide)heptonate or (b) Mitsunobu-type reactions of O-perbenzoylated methyl (α-d-gluculopyranose)heptonate with bulky 2-nitrophenols in the presence of diethyl azodicarboxylate (DEAD) and PPh. Catalytic hydrogenation (H-Pd/C) or partial reduction (e.g.

Glucopyranosylidene-spiro-iminothiazolidinone, a new bicyclic ring system: synthesis, derivatization, and evaluation for inhibition of glycogen phosphorylase by enzyme kinetic and crystallographic methods.

The reaction of thiourea with O-perbenzoylated C-(1-bromo-1-deoxy-β-D-glucopyranosyl)formamide gave the new anomeric spirocycle 1R-1,5-anhydro-D-glucitol-spiro-[1,5]-2-imino-1,3-thiazolidin-4-one. Acylation and sulfonylation with the corresponding acyl chlorides (RCOCl or RSO₂Cl where R=tBu, Ph, 4-Me-C₆H₄, 1- and 2-naphthyl) produced the corresponding 2-acylimino- and 2-sulfonylimino-thiazolidinones, respectively. Alkylation by MeI, allyl-bromide and BnBr produced mixtures of the respective N-alkylimino- and N,N'-dialkyl-imino-thiazolidinones, while reactions with 1,2-dibromoethane and 1,3-dibromopropane furnished spirocyclic 5,6-dihydro-imidazo[2,1-b]thiazolidin-3-one and 6,7-dihydro-5H-thiazolidino[3,2-a]pyrimidin-3-one, respectively.

Anomeric spirocycles by solvent incorporation: reactions of O-peracylated (glyculopyranose and glyculopyranosyl bromide)onamide derivatives with ketones.

Reactions of O-peracetylated (α-D-galacto-heptulopyranosyl bromide)onamide and O-perbenzoylated (α-D-gluco-heptulopyranosyl bromide)onamide with ketones in the presence of silver(I) salt promoters gave the corresponding O-peracylated 1',5'-anhydro-D-glycitol-spiro-[1',5]-4-imino-2,2-disubstituted-1,3-dioxolanes. The D-galacto configured starting compounds furnished both spiro epimers, while the D-gluco counterparts yielded only configurationally inverted products. Under acidic conditions, O-perbenzoylated α-D-gluco-heptulopyranosonamide and ketones yielded the protected 1',5'-anhydro-D-glucitol-spiro-[1',5]-2,2-disubstituted-oxazolidin-4-ones, which were O-debenzoylated by the Zemplén protocol.

New synthesis of 3-(β-D-glucopyranosyl)-5-substituted-1,2,4-triazoles, nanomolar inhibitors of glycogen phosphorylase.

O-Perbenzoylated 5-(β-D-glucopyranosyl)tetrazole was reacted with N-benzyl carboximidoyl chlorides to give the corresponding 4-benzyl-3-(β-D-glucopyranosyl)-5-substituted-1,2,4-triazoles. Removal of the O-benzoyl and N-benzyl protecting groups by base catalysed transesterification and catalytic hydrogenation, respectively, furnished a series of 3-(β-D-glucopyranosyl)-5-substituted-1,2,4-triazoles with aliphatic, mono- and bicyclic aromatic, and heterocyclic substituents in the 5-position. Enzyme kinetic studies revealed these compounds to inhibit rabbit muscle glycogen phosphorylase b: best inhibitors were the 5-(4-aminophenyl)- (Ki 0.