Synthesis and spectral characteristics of some unusual fatty esters of podophyllotoxin

Five fatty ester derivatives of podophyllotoxin have been prepared by react ing the corresponding fatty acids with the hydroxy group of podophyllotoxin in the presence of dimethylaminopyridine and N,N-dicyclohexylcarbodiimide. The fatty acids incorporated are: 9,12-epoxy-9,11-octadecadienoic acid, oc tadec-11E-en-9-ynoic acid, 11,12-E-epoxy-octadec-9-ynoic acid, octadeca-9Z, 11E-dienoic acid and 9,10-dibromooctadecanoic acid. The average yield of es terification was > 95% and the structures of the products were confirmed by a combination of nuclear magnetic resonance spectroscopic and mass spectro metric analyses. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved .