title: Preparation of alpha-(2,2-diphenylhydrazino)lactones and related compounds by radical cyclization: use of glyoxylic acid hydrazone derivatives.
abstract: Glyoxylic acid diphenylhydrazone (2a) and the corresponding O-benzyloxime (2b) are easily esterified in high yield by beta-bromo alcohols. The resulting esters undergo radical cyclization to alpha-(2,2-diphenylhydrazino)- or alpha-[(phenylmethoxy)amino]lactones on treatment with tributyltin hydride. Esters for radical cyclization were also made using a beta-(phenylseleno) alcohol and an enol ether. Several derivatives of glyoxylic acid were evaluated, but none was as effective as 2a or 2b. The imine 28 was prepared by an indirect route; it undergoes radical cyclization with displacement of the nitrogen substituent (28 --> 30) so that an alpha-amino lactone can be generated by acid hydrolysis of the cyclization product.
authors: Chemistry Department, University of Alberta, Edmonton, Alberta, Canada T6G 2G2. derrick.clive@ualberta.ca
authors: D L
authors: DL
authors: Clive
authors: J
authors: J
authors: Zhang
authors: R
authors: R
authors: Subedi
authors: V
authors: V
authors: Bouétard
authors: S
authors: S
authors: Hiebert
authors: R
authors: R
authors: Ewanuk