Heterocyclic Synthesis from the Reaction of Aryl Cyanate with Malonyl Chloride and Bromomalonyl Chloride

摘要

Substituted aromatic cyanate reacts with malonyl chloride to yield 7-chloro-2-aryloxy-4H,5H-pyrano[3,4-e][l,3]oxazine-4,5-dione(3).Water reacts with 7-chloro-2-phenoxy-4H,5H-pyrano[3,4-e][l,3]oxazine-4,5-dione(3a),producing phenyl(6-chloro-4-hydroxy-2-oxo-2H-pyran-3-yl)carbonylcarbamate(8).Compound 3a reacts with morpholine in the presence of anhydrous potassium carbonate to yield phenyl(4-hydroxy-6-morpholin-4-yl-2-oxo-2H-pyran-3-yl)carbonylcarbainate(9).Product 9 was also produced from the reaction of compound 8 with morpholine.Substituted aromatic cyanate induces the self-condensation of bromomalonyl chloride,yielding 3,5-dibromo-6-chloro-4-hydroxy-2-oxo-3,4-dihydro-2H-pyran-3-carboxylic acid chloride(intermediate 14)which then cyclized and produced 6-bromo-7-chloro-2-aryloxy-4H,5H-pyrano-[3,2-e][l,3]oxazine-4,5-dione(4-pyrano-oxazine)(15)and not the expected 8-bromo-7-chloro-2-aryloxy-4H,5H-pyrano-[3,4-e][l,3] oxazine-4,5-dione(16).