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.

N-(4-Substituted-benzoyl)-N'-(β-d-glucopyranosyl)ureas as inhibitors of glycogen phosphorylase: Synthesis and evaluation by kinetic, crystallographic, and molecular modelling methods.

N-(4-Substituted-benzoyl)-N'-(β-d-glucopyranosyl) ureas (substituents: Me, Ph, Cl, OH, OMe, NO(2), NH(2), COOH, and COOMe) were synthesised by ZnCl(2) catalysed acylation of O-peracetylated β-d-glucopyranosyl urea as well as in reactions of O-peracetylated or O-unprotected glucopyranosylamines and acyl-isocyanates. O-deprotections were carried out by base or acid catalysed transesterifications where necessary. Kinetic studies revealed that most of these compounds were low micromolar inhibitors of rabbit muscle glycogen phosphorylase b (RMGPb).

Halogen-substituted (C-β-D-glucopyranosyl)-hydroquinone regioisomers: synthesis, enzymatic evaluation and their binding to glycogen phosphorylase.

Electrophilic halogenation of C-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl) 1,4-dimethoxybenzene (1) afforded regioselectively products halogenated at the para position to the D-glucosyl moiety (8, 9) that were deacetylated to 3 (chloride) and 16 (bromide). For preparing meta regioisomers, 1 was efficiently oxidized with CAN to afford C-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl) 1,4-benzoquinone 2 which, in either MeOH or H(2)O-THF containing few equivalents of AcCl, added hydrochloric acid to produce predominantly meta (with respect to the sugar moiety) chlorinated hydroquinone derivatives 5 and 18, this latter being deacetylated to 4. The deacetylated meta (4, 5) or para (3, 16) halohydroquinones were evaluated as inhibitors of glycogen phosphorylase (GP, a molecular target for inhibition of hepatic glycogenolysis under high glucose concentrations) by kinetics and X-ray crystallography.

The binding of β-d-glucopyranosyl-thiosemicarbazone derivatives to glycogen phosphorylase: A new class of inhibitors.

Glycogen phosphorylase (GP) is a promising target for the treatment of type 2 diabetes. In the process of structure based drug design for GP, a group of 15 aromatic aldehyde 4-(β-d-glucopyranosyl)thiosemicarbazones have been synthesized and evaluated as inhibitors of rabbit muscle glycogen phosphorylase b (GPb) by kinetic studies. These compounds are competitive inhibitors of GPb with respect to α-d-glucose-1-phosphate with IC(50) values ranging from 5.

Synthesis of new glycosyl biuret and urea derivatives as potential glycoenzyme inhibitors.

O-peracetylated 1-(beta-D-glucopyranosyl)-5-phenylbiuret was prepared in the reaction of O-peracetylated beta-D-glucopyranosylisocyanate and phenylurea. The reaction of O-peracetylated N-beta-D-glucopyranosylurea with phenylisocyanate furnished the corresponding 1-(beta-D-glucopyranosyl)-3,5-diphenyl- as well as 3-(beta-D-glucopyranosyl)-1,5-diphenyl biurets besides 1-(beta-D-glucopyranosyl)-3-phenylurea. O-Peracetylated 1-(beta-D-glucopyranosyl)-5-(beta-D-glycopyranosyl)biurets were obtained in one-pot reactions of O-peracetylated beta-D-glucopyranosylamine with OCNCOCl followed by a second glycopyranosylamine of beta-D-gluco, beta-D-galacto and beta-D-xylo configurations.

Glucose-based spiro-isoxazolines: a new family of potent glycogen phosphorylase inhibitors.

A series of glucopyranosylidene-spiro-isoxazolines was prepared through regio- and stereoselective [3+2]-cycloaddition between the methylene acetylated exo-glucal and aromatic nitrile oxides. The deprotected cycloadducts were evaluated as inhibitors of muscle glycogen phosphorylase b. The carbohydrate-based family of five inhibitors displays K(i) values ranging from 0.

Naturally occurring pentacyclic triterpenes as inhibitors of glycogen phosphorylase: synthesis, structure-activity relationships, and X-ray crystallographic studies.

Twenty-five naturally occurring pentacyclic triterpenes, 15 of which were synthesized in this study, were biologically evaluated as inhibitors of rabbit muscle glycogen phosphorylase a (GPa). From SAR studies, the presence of a sugar moiety in triterpene saponins resulted in a markedly decreased activity ( 7, 18- 20) or no activity ( 21, 22). These saponins, however, might find their value as potential natural prodrugs which are much more water-soluble than their corresponding aglycones.

Crystallographic and computational studies on 4-phenyl-N-(beta-D-glucopyranosyl)-1H-1,2,3-triazole-1-acetamide, an inhibitor of glycogen phosphorylase: comparison with alpha-D-glucose, N-acetyl-beta-D-glucopyranosylamine and N-benzoyl-N'-beta-D-glucopyranosyl urea binding.

4-Phenyl-N-(beta-D-glucopyranosyl)-1H-1,2,3-triazole-1-acetamide (glucosyltriazolylacetamide) has been studied in kinetic and crystallographic experiments with glycogen phosphorylase b (GPb), in an effort to utilize its potential as a lead for the design of potent antihyperglycaemic agents. Docking and molecular dynamics (MD) calculations have been used to monitor more closely the binding modes in operation and compare the results with experiment. Kinetic experiments in the direction of glycogen synthesis showed that glucosyltriazolylacetamide is a better inhibitor (K(i) = 0.

FR258900, a potential anti-hyperglycemic drug, binds at the allosteric site of glycogen phosphorylase.

FR258900 has been discovered as a novel inhibitor of human liver glycogen phosphorylase a and proved to suppress hepatic glycogen breakdown and reduce plasma glucose concentrations in diabetic mice models. To elucidate the mechanism of inhibition, we have determined the crystal structure of the cocrystallized rabbit muscle glycogen phosphorylase b-FR258900 complex and refined it to 2.2 A resolution.