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

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.