Experimental antiulcer drugs. 2. 2-Substituted 2,4,5,6-tetrahydro-1,3,4,6,6-pentamethylcyclopenta[c]pyrrole-4-carboxamides.

Condensation of a 1-substituted 2,5-dimethylpyrrole 6 with 2 mol of 2-amino-2-methylpropionitrile in hot acetic acid yielded a 2-substituted 2,4,5,6-tetrahydro-1,3,4,5,6,6-pentamethylcyclopenta[c]pyrrole-4-carbonitrile (4). Hydrolysis of the nitriles to the amides gave a group of compounds which were active as antisecretory agents in the pyloric-ligated rat. Outstanding in this respect was the 2-phenyl derivative 5b, the most active compound in the series. It did not possess anticholinergic properties. In contrast to the indoles and pyrroles reported earlier, 5b demonstrated marked activity in blocking gastric acid secretion in the histamine-stimulated dog.