Kam W Law

PREDICTION OF POLYMER GLASS TRANSITION TEMPERATURES USING A GENERAL QUANTITATIVE STRUCTURE-PROPERTY RELATIONSHIP TREATMENT

A novel approach to the prediction of the physical properties of polymers is presented. A QSPR study, involving the use of a newly developed statistical package, CODESSA, is described for the Tg of a set of 22 low molecular weight polymers which gave a four-parameter equation with R2 = 0.928. The physical significance of the descriptors selected is discussed.

The synthesis and chemistry of azolenines. Part 2. A general synthesis of pyrrole-2-carboxylic acid derivatives by the reaction of 2H-azirines with enamines, and the crystal and molecular structure of ethyl 3-phenyl-4,5,6,7-tetrahydroindole-2-carboxylate

A new general synthesis of 1H-pyrrole-2-carboxylic acid derivatives is described. Reaction between appropriately substituted 2H-azirines and enamines gives a mixture of 2,3- and 3,4-dihydropyrroles, which on acid treatment yields the title compounds in moderate to high yields. Attempts to extend the reaction to the preparation of 2H- and 3N-pyrroles were unsuccessful; reasons are discussed. The crystal and molecular structure of ethyl 3-phenyl-4,5,6,7-tetrahydroindole-2-carboxylate has been determined. The molecules pack in highly coplanar, centrosymmetric, hydrogen-bonded pairs.

The chemistry of N-substituted benzotriazoles. Part 1.1-(Chloromethyl)benzotriazole

The N-chloromethyl group of 1-(chloromethyl)benzotriazole undergoes nucleophilic substitution by carbon, nitrogen, phosphorus, oxygen, and sulphur nucleophiles. α-Lithiation was achieved in high yield in 1-phenylthiomethyl-, 1-phenylsulphinylmethyl-, and 1-(phenylstilphonylmethyl)benzotriazoles and the lithio derivatives reacted with a variety of electrophiles. New benzotriazolium salts were prepared by quaternization of the N-3 nitrogen with methyl iodide.