Preparation of L-alpha-phosphatidyl-D-myo-inositol 3-phosphate (3-PIP) and 3,5-bisphosphate (3,5-PIP2)

Practical, asymmetric total syntheses of the title phospholipids from a readily available myo-inositol derivative as well as short chain and cross-linkable aminoether analogues are described.     

Synthesis and some pharmacological properties of [I-β-mercaptopropionic acid, 2-(3,5-dibromo-l-tyrosine)]-8-lysine-vasopressin

The title compound, [1-β-mercaptopropionic acid, 2-(3,5-dibromo-l-tyrosine)]-8-lysine-vasopressin (X), was synthesized by condensation of Pro-Lys(Boc)-Gly-NH₂ with the cyclic peptide [1-β-mercaptopropionic acid, 2-(3,5-dibromo-l-tyrosine)]-pressinoic acid. X has no oxytocic, avian vasodepressor, pressor, or antipressor activities, but is a weak inhibitor of the responses to oxytocin in the oxytocic and avian vasodepressor assays. Its pharmacological properties are qualitatively identical to those of the corresponding analog of oxytocin, although it is a less potent antagonist than the latter compound.     

2,5-Diaminopyrimidines and 3,5-disubstituted azapurines as inhibitors of glycogen synthase kinase-3 (GSK-3)

The discovery of two classes of pyrimidine-based inhibitors of GSK-3 is described. Optimization of these series led to inhibitors with IC(50)<10nM and >100-fold selectivity over Aurora A kinase. A proposed binding mode of 21b is presented. One compound (33) of the pyrimidine series showed promising pharmacokinetic parameters.     

Preparation of ethyl 3R,5S-6-(benzyloxy)-3,5-dihydroxy-hexanoate by recombinant diketoreductase in a biphasic system

Diketoreductase from Acinetobacter baylyi ATCC 33305 is a unique carbonyl reductase, which can stereoselectively reduce ethyl-6-(benzyloxy)-3,5-dioxohexanoate to ethyl 3R,5S-6-(benzyloxy)-3,5-dihydroxy-hexanoate, an advanced intermediate for statin drugs. In the present study, we explored an aqueous-organic biphasic reaction system to make this biocatalyst more practical and valuable. Different from most oxidoreductases, diketoreductase displayed an excellent tolerance to certain organic solvents without any changes on the catalytic properties. After optimizing reaction conditions, an aqueous-hexane (1:1) biphasic system was established for the preparation of 3R,5S-dihydroxy product by diketoreductase. This system was further scaled up to 0.5 l at a substrate concentration of 105 g/l (378 mM), and the 3R,5S-hydroxy product was obtained with a yield of 83.5% and excellent stereoselectivity (de>99.5%, ee>99.5%).     

Preparation of 3-epi-ecdysone and 3-epi-20-hydroxyecdysone

3-Dehydro-ecdysone and 5-dehydro-20-hydroxyecdysone were prepared and characterized. Reduction of these compounds with NaBH₄ gave 3-epi-ecdysone and 3-epi-20-hydroxyecdysone, which were characterized fully by mass and p.m.r. spectrometry as well as by derivative formation.     

3-Chloro-, 2,3- and 3,5-dichlorobenzoate co-metabolism in a 2-chlorobenzoate-degrading consortium: role of 3,5-dichlorobenzoate as antagonist of 2-chlorobenzoate degradation

A study was made of the metabolic and co-metabolic intermediates of 2- and 3-chlorobenzoate, 2,3- and 3,5-dichlorobenzoate to elucidate the mechanism(s) involved in the negative effects observed on the growth of a chlorobenzoate-degrading microbial consortium in the presence of mixed chlorobenzoates. 2-Chloro-muconate accumulated as the end-product in the cultural broths of the microbial consortium during growth on 2-chlorobenzoate; the same 2-chloromuconate was identified in the reaction mixtures of resting cells pre-grown on 2-chlorobenzoate and exposed to 3-chloro- and 2,3-dichlorobenzoate, while in similar experiments 1,2-dihydroxy-3,5-dichloro-cyclohexa-3,5-dienoate was detected as dead-end product of 3,5-dichlorobenzoate co-metabolism. These results suggest an initial degradative attack by 2-chlorobenzoate induced dioxygenase(s). The role of 3,5-dichlorobenzoate as an antagonist of 2-chlorobenzoate degradation was also studied: in the presence of mixed 2-chloro- and 3,5-dichlorobenzoate, the 3,5-dichlorobenzoate preferential uptake by the resting cells of the chlorobenzoate-degrading consortium was observed. 2-Chlorobenzoate entered the cells only after the complete removal of the co-substrate. In growing cells experiments, the addition of 1,2-dihydroxy-3,5-dichloro-cyclohexa-3,5-dienoate, the 3,5-dichlorobenzoate co-metabolite, to 2-chlorobenzoate exerted the same antagonistic effect of the parent compound, inhibiting both the microbial growth and the degradative process. These data are discussed, allowing us to attribute the inhibitory effects observed to a substrate/co-substrate competition, though other additional causes may not be totally excluded.     

Metabolism of 3-chloro-, 4-chloro-, and 3,5-dichlorobenzoate by a pseudomonad.

Pseudomonas sp. WR912 was isolated by continuous enrichment in three steps with 3-chloro-, 4-chloro-, and finally 3,5-dichlorobenzoate as sole source of carbon and energy. The doubling times of the pure culture with these growth substrates were 2.6, 3.3, and 5.2 h, respectively. Stoichiometric amounts of chloride were eliminated during growth. Oxygen uptake rates with chlorinated benzoates revealed low stereospecificity of the initial benzoate 1,2-dioxygenation. Dihydrodi-hydroxybenzoate dehydrogenase, catechol 1,2-dixoygenase, and muconate cycloisomerase activities were found in cell-free extracts. The ortho cleavage activity for catechols appeared to involve induction of isoenzymes with different stereospecificity towards chlorocatechols. A catabolic pathway for chlorocatechols was proposed on the basis of similarity to chlorophenoxyacetate catabolism, and cometabolism of 3,5-dimethylbenzoate by chlorobenzoate-induced cells yielded 2,5-dihydro-2,4-dimethyl-5-oxo-furan-2-acetic acid.     

Metabolism of 3-chloro-, 4-chloro-, and 3,5-dichlorobenzoate by a pseudomonad.

Pseudomonas sp. WR912 was isolated by continuous enrichment in three steps with 3-chloro-, 4-chloro-, and finally 3,5-dichlorobenzoate as sole source of carbon and energy. The doubling times of the pure culture with these growth substrates were 2.6, 3.3, and 5.2 h, respectively. Stoichiometric amounts of chloride were eliminated during growth. Oxygen uptake rates with chlorinated benzoates revealed low stereospecificity of the initial benzoate 1,2-dioxygenation. Dihydrodi-hydroxybenzoate dehydrogenase, catechol 1,2-dixoygenase, and muconate cycloisomerase activities were found in cell-free extracts. The ortho cleavage activity for catechols appeared to involve induction of isoenzymes with different stereospecificity towards chlorocatechols. A catabolic pathway for chlorocatechols was proposed on the basis of similarity to chlorophenoxyacetate catabolism, and cometabolism of 3,5-dimethylbenzoate by chlorobenzoate-induced cells yielded 2,5-dihydro-2,4-dimethyl-5-oxo-furan-2-acetic acid.     

Preparation and biochemical properties of PGH3

PGH3 was biosynthesised from all-cis-5,8,11,14,17-eicosapentaenoic acid (20:5 omega 3) by an acetone-pentane powder of ram seminal vesicles and its structure was confirmed by GLC-MS after its reduction to PGF 3 alpha. PGH3 was transformed by horse platelet microsomes to TXB3, and by aortic microsomes to delta 17-6-keto-PGF 1 alpha. The structures of these compounds were confirmed by GLC-MS.     

Preparation, hydrolysis and intramolecular transesterification of 3'-deoxy-3'-thioinosine 3'-S-dimethylphosphorothiolate

The hydrolytic reactions of the dimethyl ester of 3'-deoxy-3'-thioinosine 3'-S-phosphorothiolate have been followed over a wide aciditiy range by HPLC. At pH > 3, only hydroxide ion catalyzed isomerization to the 2'-dimethylphosphate takes place, whereas under more acidic conditions hydrolysis to the 2'-monomethylphosphate and 3'-S-monomethylphosphorothiolate competes. The latter is the only product accumulating in very acidic solutions (1 M hydrochloric acid). Mechanisms of the reactions are discussed.     

Preparation of 3-deoxy-3-deuteroestrone and 3-deoxy-4-14C-estrone

3-Deoxy-3-deuteroestrone (1,3,5(10)-estratrien-17-one-3-d) and 3-deoxy-4-¹⁴C-estrone (1 ,3 ,5(10)-estratrien-17-one-¹⁴C) have been prepared. The mechanism of reductive dehalogenation of aryl iodides with lithium aluminum deuteride is discussed. The ¹³C-NMR spectrum of 3-deoxy-3-deuteroestrone is discussed.     

Preparation of chiral stationary phase for HPLC based on immobilization of cellulose 3,5-dimethylphenylcarbamate derivatives on silica gel

The immobilization of cellulose 3,5-dimethylphenylcarbamate derivatives having a polymerizable vinyl group, i.e., 4-vinylphenylcarbamate or 2-methacyloyloxyethylcarbamate, on silica gel was examined under various conditions. The immobilization was basically conducted through the radical copolymerization of the derivatives with a vinyl monomer. Several factors, such as the vinyl monomer content and the type and amount of the vinyl group of cellulose derivatives, were varied. The introduction of a vinyl group onto the silica surface resulted in a more efficient immobilization of the cellulose phenylcarbamate derivatives on the silica gel. As the content of the vinyl group on the cellulose derivatives was reduced, the immobilization became more difficult, although the obtained phase exhibited higher chiral recognition abilities. These immobilized CSPs could be stably used with the eluent containing 10% chloroform, which cannot be used for the phase prepared by coating the derivatives on silica gel. Some racemates were better resolved on the immobilized CSP by using chloroform as a component of the eluent.