Abstract: The invention relates to the preparation of N-.alpha.-alkoxyethyl-carboxylic acid amides from dimethyl acetal and a carboxylic acid amide such as acetamide and to the preparation of secondary N-vinyl carboxylic acid amides such as N-vinyl acetamide therefrom.The reaction of dimethyl acetal and the carboxylic acid amide involves an equilibrium disproportionation wherein excess dimethyl acetal is used in sufficient amounts, e.g., in a molar ratio of from about 2 to 60:1 mole ratio, so as to force the equilibrium to the desired N-.alpha.-alkoxyethyl-carboxylic acid amide intermediate product. Equilibrium is reached in about 0.1 to 150 hours at a temperature about 0.degree. to 100.degree. C. The intermediate N-.alpha.-alkoxyethyl-carboxylic acid amide is pyrolyzed in accordance with a known pyrolysis reaction so as to obtain the corresponding N-vinyl acetamide.