Is the magnetic shielding effect of a lactone group the simple sum of those of a ketone and an ether?
摘要:
3-Oxo-4-oxa-5 alpha-androstanone (1) was synthesized in order to obtain the NMR shielding parameters for lactone group. The assignment of H-1-NMR and substituent-induced shifts (SIS) from the corresponding androstanone (2) are presented. A simple sum of the magnetic shieldings of ketone and ether can satisfactorily reproduce the observed SIS values due to the lactone group of 1. (C) 1999 Elsevier Science Ltd. All rights reserved.