Patent / 2012
Electrophilic alkylating reagents, their preparation and use
Hovione Inter. Ltd.
The invention relates to sulfonium electrophilic alkylating reagent of formula I, wherein is an aryl group, R2 is an alkyl group, R3 is a substituted Ph group, wherein the no. of substituents (n) is greater than 2 and R4 is an anion, and salts thereof, methods for their prepn. and methods for the prepn. of a wide variety of alkylated biol. active compds. using such reagents. Example compd. II was prepd. by reacting Me Ph sulfoxide (prepn. shown) with 1,2,3,4-tetramethylbenzene in the presence of trifluoromethanesulfonic anhydride in 94% yield as a white solid. Example compd. II was then used for prepn. of (10R,13S,17R)-Me 11,17-dihydroxy-10,13-dimethyl-3-oxo-6,7,8,9,10,11,12,13,14,15,16,17-dodecahydro-3H-cyclopenta[a]phenanthrene-17-carboxylate by methylation of the corresponding carboxylic acid in the presence of Cs2O3 in dichloromethane at room temp. Tiotropium bromide (III) was prepd. similarly.