Both the Schiff base-mediated 2-keto-4-hydroxyglutarate aldolase of liver and the metal-activated a-keto-/3-deoxyhexarate aldolase of Escherichia coli condense pyruvate and glyoxylate to form (4-RS)-Z-keto-4-hydroxyglutarate. Both enzymes catalyzed a condensation between [3-3H3]pyruvate and glyoxylate. It was found that C-C synthesis occurred 6 to 7 times faster than C-T bond cleavage. Thus, py...

Based upon comprehensive theoretical investigations and known experimental observations, we predict the existence of the double-chain planar D(2h) B(4)H(2)(1), C(2h) B(8)H(2)(3), and C(2h) B(12)H(2)(5) which appear to be the lowest-lying isomers of the systems at the density functional theory level. These conjugated aromatic borenes turn out to be the boron hydride analogues of the conjugated e...

Designing and searching for a high thermal conductivity material in both bulk nanoscale is highly demanding electronics cooling. In this work, we studied the of 2H-Germanium Carbide(2H-GeC) using first principles calculations. At 300 K, are reporting 1350 Wm?1K?1 1050 along a-axis c-axis respectively pure 2H-GeC. These values 130% higher than 2H-silicon carbide 20% lower cubic germanium carbide...

(25R)-26-Hydroxycholesterol (I) was synthesized in six steps from (22Z,25R)-cholesta-5,22-diene-3 beta,26-diol (II) in 31% overall yield. The 26-tert-butyldiphenylsilyl ether of II was converted via its 3 beta-tosylate to (22Z,25R)-6 beta-methoxy-26-(tert- butyldiphenylsilyloxy)-3 alpha,5-cyclo-5 alpha-cholest-22-ene (V). Removal of the 26-silyl group of V gave (22Z,25R)-6 beta-methoxy-3 alpha,...

In the title compound, C(15)H(10)O(2), a 3-phenyl derivative of the coumarin (also known as 2H-chromen-2-one or 2H-1-benzopyran-2-one) scaffold, the C(p)-C(p)-C(c)-C(c) torsion angle between the coumarin (c) ring system and the phenyl (p) ring is -47.6 (2)°.

A ruthenium-catalyzed intermolecular [3 + 2] cycloaddition of 2H-azirines and activated alkynes is reported, which provides polysubstituted pyrroles in moderate to good yields. This approach features a C-N bond cleavage of 2H-azirines by a ruthenium catalyst. The results of this study would provide a complementary method to synthesize polysubstituted pyrroles from the known 2H-azirine approache...

Feeding synthetic [2beta-2H]- and [2alpha-2H]-cholesterols to the hairy roots of Ajuga reptans var. atropurpurea and 2H-NMR analysis of the biosynthesized 20-hydroxyecdysone revealed that hydroxylation at C-2 proceeds with retention of configuration. Feeding [2alpha,3alpha-2H2]cholesterol followed by 2H-NMR analysis of the 2,3,22-triacetate of the resulting 20-hydroxyecdysone ruled out a mechan...

In a condensation between [3-3H3]pyruvate and D-glyceraldehyde-3-P as catalyzed by 2-keto-3-deoxygluconate-6-P aldolase (EC 4.1.2.14) of Pseudomonas putida, C--C synthesis occurred appreciably faster than C--3H bond breaking. Since tritium is present in tritiated pyruvate in tracer amounts, this result showed hydrogen isotope discrimination in pyruvate deprotonation and suggests enolpyruvate ge...

Exhaustive hydro-distillation of the bark, heartwood and fruits of Cryptocarya massoy (Lauraceae) afforded pale yellow-coloured oils in 0.7, 1.2 and 1.0 % yields, respectively. Detailed chemical evaluation of these distillates using GC/MS revealed the major components in the bark and the heartwood oils to be the C-10 (5,6-dihydro-6-pentyl-2H-pyran-2-one) and C-12 (5,6-dihydro-6-heptyl-2H-pyran-...