Patent ID: 7598376

Claim:
A process for the preparation of a 4,5-diacyl-[1,4,5]-oxadiazepine comprising: (1) reacting N,N′-diacylhydrazine with a 2,2′-disubstituted diethyl ether in a polar solvent in the presence of a base and at an elevated temperature to form the corresponding 4,5-diacyl-[1,4,5]-oxadiazepine and (2) optionally reacting the 4,5-diacyl-[1,4,5]-oxadiazepine with a hydrohalic acid in a polar solvent at an elevated temperature to form the corresponding [1,4,5]-oxadiazepine, wherein in reaction step (1) the solvent is selected from the group consisting of DMSO, sulfolane, NMP and DMA and wherein the base is selected from the group consisting of hydroxides, carbonates, alcoholates of alkali and alkaline earth metals, and mixtures thereof and in reaction step (2) the polar solvent is an alcohol having a boiling noint above 100° C.