Based on 2-amino-7,7-dimethyl-4-(3-nitrophenyl)-5-oxo-5,6,7,8-tetrahydro-4-chromene-3-carbonitrile and formalin when heated in ethanol was obtained 7-(ethoxymethyl)-4,4-dimethyl-2-(3-nitrophenyl)-2,6,8-trioxo-5,7-diazaspirobicyclo[3.3.1nonane-3,1-cyclohexane]-1-carbonitrile, the structure of which has been studied using spectral methods and X-ray diffraction analysis.
A.V. Churakov (Wed,) studied this question.