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The effect of temperature on enantioselectivity and desymmetrization in the acetylation of 2-phenyl-1,3-propanediol (1a), 2-benzyl-1,3-propanediol (1b), 2-methyl-2-phenyl-1,3-propanediol (1c) and 2-benzyl-2-methyl-1,3-propanediol (1d) by a novel lipase (CSL) isolated from the yeast Cryptococcus spp. S-2 was studied. Desymmetrization of 1a, 1c and 1d by CSL-catalyzed acetylation was observed in the temperature range of −20°C to 40°C, while diacetylation of 1b occurred considerably even at 0°C. The kinetic parameters of the selectivity indicated that the acetylation of 1a is an entropy controlled process whereas the reaction of 1c and 1d is mainly controlled by the enthalpy term. In the monoacetylation of the diol 1d, the preferred configuration in the enantiomeric induction by CSL was opposite to that of immobilized porcine pancreatic lipase (PPL).

The Horner-Wadsworth-Emmons reaction of diphenylphosphonoacetamides [(PhO) 2 P(O)CH 2 CONRR'] ( 2a : R, R' = CH 2 Ph; 2b : R = CH 2 Ph, R' = H; 2c : R = Me, R' = OMe) was examined. The reaction of ...

(-)-Loliolide (1) showing an inhibitory activity for lettuce seed germination was isolated from leaves of Equisetum arvense. It is rare that this active compound occurred from the family Equisetaceae.

Selectivity of alkylation of and that of deuteration of methyl groups attached to the pyrimidine ring of tetraazathiapentalenes are discussed.

5-Amino-3-methyl- and 5-amino-3-phenylisothiazoles (3a and 3b) afforded 1 : 1 adducts with aromatic nitriles and imidates. On the basis of their spectral data and the structure of hydrolysis products, the adducts were identified as 3-substituted 5-(2-aminovinyl)-1,2,4-thiadiazole derivatives (2a-g), where ring transformation took place from isothiazole to 1,2,4-thiadiazole.