Piperidine → Spiro(cyclopentane-1,1'-indan)-3'-ylideneacetonitrile

Participants

Reaction Steps

To a mixture of cyanoacetic acid (85 g; 1.0 moles) and spiro(cyclopentane-1,1'-indan)-3'-one (186 g; 1.0 moles) there is added piperidine (85.2 g; 1.0 moles) dropwise under agitation and cooling at such a rate that the temperature does not exceed 40°-60° C. After addition of benzene (300 ml) the mixture is refluxed for 24 hours with continuous separation of the water formed. Benzene and piperidine are distilled off under reduced pressure and the oil obtained is distilled in vacuum. At 130°-140° C./1 torr there is obtained a colourless oil consisting of the title nitrile as well as the isomer spiro(cyclopentane-1,1'-indene)-3'-ylacetonitrile and a small amount of unreacted ketone. The mixture is dissolved in hot hexane and cooled, and then spiro(cyclopentane-1,1'-indan)-3'-ylideneacetonitrile crystallizes as colourless crystals of mp 82° C.

Provenance & Evidence