Chemistry of cyanoacetylenes. Part IV. Preparation and reactions of cyano-ynamines and the corresponding cyano-enamines
Cyano-ynamines prepared from cyanochloroacetylene and dimethyl- and diethyl-amine, piperidine, morpholine, and pyrrolidine were converted into the corresponding cyanoacetamides on acidic hydrolysis. Treatment of the cyano-ynamines with benzylamine or secondary amines in the presence of boron trifluoride–ether afforded linear cyano-enamines : reaction with methyl anthranilate gave 3-cyano-4-hydroxyquinoline derivatives. Treatment of cyano-ynamines with alcohols gave cyano(alkoxy)-enamines. Acidic hydrolysis of cyano-enamines and cyano-(alkoxy)-enamines afforded cyanoacetamides and a mixture of the corresponding cyano-acetamides and -acetates respectively. 1,3-Dipolar cycloaddition of diethylamino- or morpholino-cyanoacetylene, to 5-nitro-2-furan-carbonitrile oxide afforded 5-diethylamino- and 5-morpholino-3-(5-nitro-2-furyl)isoxazole, which were identical with the 1,3-dipolar cyclo-adducts of the (NN-diethyl)- and 1-(NN-dimorpholyl)-cyano-enamines to the same nitrile oxide. A similar addition of the cyano(alkoxy)-enamine however, gave a mixture of 5-O- and 5-N-substituted isoxazole. Treatment of cyanopiperidinoacetylene with methanesulphonyl chloride in the presence of triethylamine afforded a simple adduct of methylsulphonylmethanesulphonyl chloride with a cyano-enamine-type structure; similar treatment of 1,1-diethylamino-2-cyanoethylene gave 1,1-diethylamino-2-cyano-2-(methylsulphonylmethanesulphonyl)ethylene. When treated with phenyl isocyanate or isothiocyanate, cyano(alkoxy)- enamines afforded simple addition products.