Dimerization is a reaction characteristic of 1, 3-butadiene and its derivatives. Thus, it was not surprising to find that 2-cyano-l13-butadiene on standing in an ice-box, even though picric acid was present, gradually changed to a low-melting solid. The closely related 2-chloro-l13- butadiene has been shown to yield two dimers, the first a cyclohexene derivative and the second a cyclooctadiene derivative (II). a Hence we have considered similar possibilities ...
