Patent ID: 6433213
Filing Date: 2002-08-13
Classification: C07B,C07C,C07D,Y02P

Abstract:
A process for the preparation of a compound of Formula I wherein R is alkyl,NCâ€”CH2â€”, or PGâ€”Oâ€”CH2â€” wherein PG is a protecting group; and R1 is alkyl, or â€”CH2â€”CO2R6 wherein R6 is alkyl; which comprises: Step (a) treating a compound of Formula II or a compound of Formula III wherein R and R1 are as defined above with a trialkylborane or dialkylalkoxyborane or a mixture of a trialkylborane and a dialkylalkoxyborane in a solvent; Step (b) adding an alkali metal hydride at about âˆ’110Â° C. to about âˆ’50Â° C.; Step (c) concentrating the reaction by distillation to afford a compound of Formula I and a distillate containing alkylborane species; and Step (d) treating additional compound of Formula II or III with the distillate from Step (c) containing recovered alkylborane species, and repeating Steps (b) and (c) as desired to afford additional compound of Formula I.