Synthesis of 3,5-Isoxazolidinediones and 1H-2,3-Benzoxazine-1,4(3H)-diones from Aliphatic Oximes and Dicarboxylic Acid Chlorides

[Image: see text] The synthesis of the title compounds was carried out by reacting dicarboxylic acid chlorides with oximes in the presence of excess triethylamine. Disubstituted malonyl chlorides gave 2-alkenyl-4,4-dialkyl-3,5-isoxazolidinediones (8a–f) and 2,2′-ethylidene-bis[4,4-dialkyl-3,5-isoxazolidinedione]s (9a–f). Compounds 9 were formed from 8 and its N-unsubstituted 3,5-isoxazolidinedione decomposition product. Phthaloyl chlorides reacted with acetone oxime to yield 3-(1-methylethenyl)-1H-2,3-benzoxazine-1,4(3H)-diones (16a–e). Products 16 spontaneously decomposed to give N-unsubstituted 1H-2,3-benzoxazine-1,4(3H)-diones (17a–e) at rates that were dependent on temperature and solvent. Kinetic studies showed that two of the compounds decomposed by zero-order kinetics under neutral conditions. Butanedioyl chloride did not produce a cyclic product.