225112-81-2Relevant academic research and scientific papers
Synthesis and Structure of 2-(Triphenylphosphoranylideneamino)tropone and Its Utility in the Preparation of New Cyclohepta-annulated Heterocycles
Yamamoto, Hiroyuki,Ohnuma, Manami,Nitta, Makoto
, p. 901 - 919 (2007/10/03)
2-(Triphenylphosphoranylideneamino)tropone 8 has been synthesized for the first time by several methods. The X-ray crystal analysis revealed that compound 8 exists as an (imino)phosphorane structure, but not as a P-O bonded oxazaphosphole structure 8'. With a view to constructing a series of new cyclohepta-annulated heterocycles, compound 8 was allowed to react with phenyl isocyanate and isothiocyanate in an aza-Wittig/electrocyclization manner to give 2H-cycloheptoxazol-2-one and its imine derivative in good combined yields. In a similar manner, reaction of compound 8 with diphenylketene and carbon disulfide afforded 2-(diphenylmethylidene)-2H-cycloheptazole and 2H-cycloheptoazole-2-thione in good yields, respectively. On the other hand, reaction of compound 8 with dimethyl acetylenedicarboxylate (DMAD) gives dimethyl cyclohepta[b]pyrrole-2,3-dicarboxylate, which subsequently reacts with DMAD to result in the formation of tetramethyl 2H-cyclohepta[2',1'-b:2',3'-b]pyrrolo[1,2-a]pyrrole-1,2,4,5-tetracarboxylate.
