Condensation reaction of 3,4‐dibenzoyl‐1‐methyl‐2,5‐diphenylpyrrole and ‐1‐phenylpyrazole with methylamine derivatives affording pyrrolo [3,4‐c]pyridine and 2H‐pyrazolo[3,4‐c]‐ and [4,3‐c]pyridines