REACTION OF STEROID-17-ALPHA-HYDROXY-17-CARBOXYLIC ACIDS WITH CARBODIIMIDES - SYNTHESIS OF STEROID-17-SPIRO-5'-[2'-IMINO-4'-OXAZOLIDINONES]AND 17-SPIRO-5'-[2',4'-OXAZOLIDINEDIONES]
S. Noguchi et al., REACTION OF STEROID-17-ALPHA-HYDROXY-17-CARBOXYLIC ACIDS WITH CARBODIIMIDES - SYNTHESIS OF STEROID-17-SPIRO-5'-[2'-IMINO-4'-OXAZOLIDINONES]AND 17-SPIRO-5'-[2',4'-OXAZOLIDINEDIONES], Chemical and Pharmaceutical Bulletin, 42(8), 1994, pp. 1567-1570
Steroid-17 alpha-hydroxy-17-carboxylic acids (2) were allowed to react
with carbodiimides (DCCI, DPCI, DTCI, EDCI) to afford 17-spiro-5'-[2'
-imino-4'-oxazolidinones] (3-5, 11), 17-spiro-5'-[2',4'-oxazolidinedio
nes] (77-9) and N-acylureas (10), depending on the reaction conditions
. The reaction in acetonitrile in the presence of CuCI2 gave 3-5, whil
e that in N,N-dimethylformamide gave 7-9. The reaction with DTCI under
basic conditions afforded 10 along with 9.