"A suitable method to prepare compounds of formula (I) wherein A is ???NH but R3 is other than H is by reductive amination, which comprises reaction of the corresponding compound of formula (IA) with a suitable aldehyde or ketone precursor for the group R3 in the presence of a suitable reducing agent such as sodium triacetoxyborohydride, optionally in the presence of acetic acid, and in an inert so" . . . .