Amino acid amides of 2-[(2-aminobenzyl)sulfinyl]benzimidazole as acid-stable prodrugs of potential inhibitors of H+K+ ATPase
摘要:
A series of amino acid amides of 2-[(2-aminobenzyl)sulfinyl]benzimidazole were prepared and found to possess gastric antisecretory activity on oral administration. (Glycylaminobenzyl)sulfinyl compound 23a, stable in artificial gastric juice (pH 1.2), was given orally to dogs. It was absorbed efficiently and converted into aniline derivative 7a which showed a very high plasma concentration. Compound 23a was hydrolyzed by the action of aminopeptidase present in plasma or the brush border fraction of the small intestine to release the terminal glycine. omicron-Aniline derivatives showed good activity in in vitro H+/K+-ATPase inhibition as well as in the inhibition of histamine stimulated acid secretion in isolated bullfrog gastric mucosa. Although these omicron-aniline derivatives showed no or weak gastric antisecretory activity in rat by id administration, they were active when administered ip. Therefore, these amino acid amides were considered to be acid stable prodrugs of proton pump inhibiting omicron-aniline derivatives. The mechanism of H+/K+-ATPase inhibition of 7a was also examined.
Substituted 2-[(2-benzimidazolylsulfinyl)methyl]anilines as potential inhibitors of H+/K+ ATPase
摘要:
A series of substituted 2-[(2-benzimidazolylsulfinyl)methyl]anilines were synthesized as potential inhibitors of the acid secretory enzyme H+/K+ ATPase. Substitutions on the aniline nitrogen atom resulted in potent enzyme inhibition in vitro but weak activity in gastric fistula dogs. Electron-donating substituents on the aniline ring enhanced in vitro and in vivo potency relative to the unsubstituted analogue. The potency showed a correlation to the calculated pKa of the aniline nitrogen atom. Substitutions on the aniline and benzimidazole rings did not further enhance potency. Di- and trisubstituted aniline derivatives were potent inhibitors of the enzyme system. The preferred combination of substituents were a methoxy group on the benzimidazole ring and a single alkyl group on the aniline ring. One such compound, 76, was an effective inhibitor of acid secretion in the dog and was selected for further pharmacological study.