| abstract |
A process for the preparation of 2-chloro-4- (1H-pyrazol-3-yl) benzonitrile of formula (V) ** (See formula) ** comprising the steps of a) reacting 1- (tetrahydro-2H -pyran-2-yl) -5- (4,4,5,5-tetramethyl-1,3,2-dioxa-borolan-2-yl) -1H-pyrazole of formula (I) ** (See formula) ** with 4-bromo-2-chlorobenzonitrile of formula (II) ** (See formula) ** at elevated temperature in the presence of Pd (OAc) 2, triphenylphosphine and a base in a solvent of acetonitrile water to form 2-chlorine -4- (1- (tetrahydro-2H-pyran-2-yl) -1H-pyrazol-5-yl) benzonitrile of formula (III) b) treat the compound of formula (III) in a solvent of methanol with an amount catalytic HCl; c) adding a base to neutralize the mixture; and d) isolating the compound of formula (V). |