No abstract

cis- and trans-4, 4′-Dinitro-α, α′ -dimethylstilbene were prepared by oxidation of p-nitroacetophenone hydrazone with lead dioxide in benzene, followed by treatment with sulphur dioxide. Catalytic reduction of the trans-dinitro compound gave at least 64% of trans-4,4′-diamino-α, α′-dimethylstilbene, m. p. 157.6°C, and a similar reduction of the cis-dinitro compound afforded a mixture of the cis- and trans-diamino compound which was shown to contain at least 61% of the cis-isomer. On de-amination, the trans-diamino compound yielded α, α′-dimethylstilbene melting at 107°C, and the above mixture of the cis- and trans-isomer, a mixture of the isomeric α, α′-dimethylstil-benes in which the lower melting form predominated (at least 70%). These findings establish that α, α′-dimethylstilbene, m.p. 107°C, has the trans- and the isomer, m. p. 67 °C, the cis-configuration.