At 90-120 °C, in the presence of methylcarbonate and bicarbonate methyltrioctylphosphonium salts as catalysts ([P8881][A]; [A] = MeOCO2 and HOCO2), the transesterification of non-toxic dimethyl- and diethyl-carbonate (DMC and DEC, respectively) with 1,X-diols (2 ≤ X ≤ 6) proceeds towards the formation of cyclic and linear products. In particular, 1,2-propanediol and ethylene glycol afford propy...

The title compound, C(22)H(22)O(5), crystallizes with two independent mol-ecules in the asymmetric unit, both of which possess pseudo-C(s) symmetry. The central 1,3-dioxanone rings have envelope conformations, with the C atom bearing the two methyl groups at the flap. The benzene rings of the meth-oxy-benzyl-idene units, attached in the 4- and 6-positions on the central 1,3-dioxanone rings, are...

In the title compound, C(13)H(11)N(3)O(4), the dioxane ring adopts an envelope conformation with the C atom bonded to the dimethyl group in the flap position [deviation = 0.613 (1) Å]. The nitrile group and the attached benzene ring are roughly coplanar [maximum deviation = 0.087 (1) Å]. An intra-molecular N-H⋯O hydrogen bond involving the hydrazinyl group generates an S(6) ring. The N-N and C-...

1. Aspartate-carbamoyltransferase activity was concentrated from rat-liver preparations. Only l-aspartate, beta-benzyl-l-aspartate and beta-erythro-hydroxy-dl-aspartate were carbamoylated enzymically. The K(m) for l-aspartate and carbamoyl phosphate have been determined by three methods: colorimetric procedure, radioactive assay with [(14)C]aspartate and an assay with [(14)C]carbamoyl phosphate...

A single crystal of phenylmercury chloride (PhHgCl) was obtained by serendipity from a solution of diphenylmercury (HgPh2) and dihydrolipoic acid in tetrahydrofuran / carbon tetrachloride. The crystal structure of PhHgCl is pseudotetragonal. It is best described in the orthorhombic space group Cmma with a = 6.856(1), b = 6.882(1), c = 14.309(2) A (at 193 K), and Z = 4. The Cl-Hg-C moiety of the...