Syntheses of Heterocycles by Intramolecular Acylation of Nitrile‐Hydrogen Halide Adducts

Abstract

63] a) In the fast acid hydrolyses of cyclic phosphates (Section 5.3). phosphonates (Section 5.4) and in a slightly different manner, diethyl-2-carboxyphenyl phosphonate [63 b, c] ria cyclic oxyphosphoranederivatives, an equatorial hydroxyl is formed from the phosphoryl oxygen due to the constraints involved; b) M . Gordon, V A. Nataro, and C . E. Grij'n, J. Amer Chem. Soc. 86, 1898 (1964); c) G . M Blackburn and M . J. Brown, ibid. 91, 525 (1969).[72] Review articleFive-membered, six-membered, and seven-membered aza-, diaza-, and thiazaheterocycles can be prepared by cyclization of w-cyano carboxylic acid halides in the presence of hydrogen halides in aprotic solvents. Nitrite-hydrogen halide adducts occur as intermediates in this novel heterocycle synthesis of wide application. The acylating cyclizations of nitriles in protonic media, which proceed via imidic esters or amides, are not discussed.