Barrier of rotation around N-C=bond in N,N-disubstituted 3-amino-2-arylinden-1-ones and 3-amino-2-arylindene-1-thiones

1. The activation parameters of hindered rotation around the N-C= bond in 3-N,N-dimethylamino-2-(4′-methoxyphenyl) indene-1-thione, 3-piperidino-2-phenylindene-1-thione, 3-piperidino-2-(4′-methoxyphenyl)indene-1-thione, and their oxygen analogs were determined. The barriers of rotation decrease somewhat when the dimethylamino group is replaced by the piperidino group. 2. The insertion of a OCH3 group in the p position of the 2-phenyl ring of the studied compounds has practically no effect on the ΔG≠ value of rotation around the N-C= bond. 3. The value of the barrier of inversion of the N atom and (or) conversion of the 3-piperidine ring was estimated for the 3-piperidino-2-phenylindene-1-ketone.