Studies on the synthesis of heterocyclic compounds. VII. Action of acyl halides on heterocyclic compounds containing the O‐M‐O (M P, As, Sb) bond in the ring

The action of acyl halides on heterocyclic compounds of five‐membered rings containing an O‐M‐O (M  P, As, Sb) linkage is described. The reactions were either carried out in the presence of a solvent (benzene or toluene) or by direct heating of the reagent with the substrate. In the case of arsole, stibole and stannole derivatives, the cleavage of O‐M bond and the formation of the respective mono‐ and diesters were always obtained, while with the phospholes, no cleavage of the compounds was observed. The products IIa‐c (M = Sb) have been obtained in excellent yields starting from VIa‐c and antimony trichloride. The structure of the compounds which were prepared was determined by analytical and spectroscopic methods and also by comparations with authentic samples where possible.