in Wiley InterScience (www.interscience.wiley.com).Fifteen novel 3-substituted-5-methyl-4-methylene-7-alkylsulfanyl-3,4-dihydro-pyrido [4,3-d]pyrimidine-8-carbonitriles 5a-o, were synthesized via a facile annulation process in which formation of the pyrimidine ring proceeded smoothly by the regioselective attack of a formamidate group on a neighboring carbonyl group instead of a cyano group. Bioassay results indicated that these compounds showed significant herbicidal activity at a dose of 100 lg/mL on the roots of oil rape and barnyard grass. In addition, some of these compounds displayed fungicidal activity.

Fused pyrimidine derivatives R 0515 Synthesis and Biological Activity of 4-Methylene-pyrido[4,3-d]pyrimidines. -All products (VII) exhibit herbicidal effects on the roots of oil rape and barnyard grass. In addition, especially compound (VIIa) shows significant herbicidal and antifungal activity. -(MO, W.; YAO, Y.; SHEN, Y.; HE*, H.; GU, Y.; J.

In the crystal structure of the title compound, C14H14F3O7P, the central chain, which connects the phosphate bicyclic system and the benzene ring, is made up of an approximately planar C—C(O)—O—C(H2) fragment and a C(H2)—O—C(Ph) link; the mean planes make a dihedral angle of 75.9 (2)°. The F atoms are disordered over two positions; the site occupancy factors are ca 0.6 and 0.4.