2-(Triphenylphosphoranylideneamino)tropone is synthesized for the first time and treated with heterocumulenes to give novel cyclohepta-annulated heterocycles in good yields.

Thermal react ion of tri bu tyl ( i nden -3yl i m i no) p hosp hora ne with ~l,punsaturated ketones and a Ide hydes led to a Michael-type C-C bond formation and subsequent aza-Wittig reaction to give 5H-indeno(l,2b)pyridines in good to modest yield. The products were oxidized conveniently by chromium trioxide and t-butyl hydroperoxide to give 5H-indeno[l,2-b] pyridin-5-ones, including the 4-azafluorenone alkaloid onyc h i ne.

Reaction of N-Vinyliminophosphoranes. Part 16. A New Synthesis of 5H-Indeno(1,2-b)pyridines and 5H-Indeno(1,2-b)pyridin-5-ones.-Thermal reaction of the in situ generated tributyl(inden-3-ylimino) phosphorane (Ia), which is more reactive than its stable phenyl analogue (Ib), with α,β-unsaturated ketones and aldehydes leads to a Michael-type C-C bond formation and subsequent aza-Wittig reaction to give the title compounds (III). These products are oxidized conveniently to yield the indenopyridinones (IV), including the 4-azafluorenone alkaloid onychine (IVb). - (NITTA, M.; OHNUMA, M.; IINO, Y.; J. Chem. Soc., Perkin Trans. I (1991) 5, 1115-1118 Dep. Chem., Sch. Sci. Eng., Waseda Univ., Shinjuku, Tokyo 169, Japan; EN)

2-(Triphenylphosphoranylideneamino)tropone is synthesized for the first time and treated with heterocumulenes to give novel cyclohepta-annulated heterocycles in good yields.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.