Tetrahedron Letters,Vol.26,No.5,pp 623-626,1985 oo40-4039/85 $3.00 + .OO Printed in Great Britain 01985 Peraamon Press Ltd. HOMOCYSTEINE THIOLACTONE AS PRECURSOR OF METHIONINE AMIDE : APPLICATION TO THE MODIFICATION OF PEPTIDES OF THE TACHYKININ FAMILY G. Chassaing, S. Lavielle, S. Julien and A. Marquet Laboratoire de Chimie Organique Biologique, UACNRS 040493, Universite P. & M. Curie, 4 Place Jussieu , Paris ...