Chemistry of tetraalkoxyethenes VIII† Hydrolysis and subsequent decarboxylation of ethyl 2,2,3,3-tetraalkoxy-1-cyanocyclobutanecarboxylates
Part VI, P. H. J. Ooms, L. P. C. Delbressine, J. W. Scheeren and R. J. F. Nivard, J. Chem. Soc., Perkin I, 1976, 1533;
Abstract
Treatment of ethyl 2,2,3,3-tetraalkoxy-1-cyanocyclobutanecarboxylates (7), obtained by heating tetraalkoxyethenes with ethyl 2-cyano-2-alkenoates at 100°, with a dilute methanolic solution of sodium hydroxide at 50° leads to hydrolysis of the ester function. On prolonged heating at higher temperatures the resulting products 8 decarboxylate, yielding 2,2,3>3-tetraalkoxycyclobutanecarbonitriles 9. Under these conditions the nitrile group is also partly hydrolysed to a carboxylic acid function. Depending on the pH, acidification of 8 yields either rearranged, six-membered ring compounds, viz. 4,4,5,5-tetraalkoxy-2-cyano-δ-valerolactones 12, or acyclic acetals of α-keto esters 13.
