The new generation dihydropyridine type calcium blockers, bearing 4-phenyl oxypropanolamine, display alpha-/beta-adrenoceptor antagonist and long-acting antihypertensive activities.
A new series of dihydropyridine derivatives, bearing oxypropanolamine moiety on phenyl ring at the 4-position of the dihydropyridine base, were prepared. Oxypropanolamine was synthesized by replacing the phenolic OH of vanillin or other compounds, having a phenyl aldehyde group, with epichlorohydrin, followed by cleavaging the obtained epoxide compounds with tert-butylamine, n-butylamine or 2-methoxy-1-oxyethylamino benzene (guaiacoxyethylamine), respectively. Obtained various oxypropanolamine compounds, still remaining a phenyl aldehyde moiety, were then performed by Hantzsch condensation reaction with methylacetoacetate or ethylacetoacetate, respectively, to give our new series of dihydropyridine linked with the 4-phenyl ring. These compounds were evaluated for inotropic, chronotropic, and aorta contractility that associated with calcium channel and adrenoceptor antagonist activities. Dihydropyridine derivatives that with oxypropanolamine side chain on their 4-phenyl ring associated alpha-/beta-adrenoceptor blocking activities created a new family of calcium entry and the third generation beta-adrenoceptor blockers. Optimizing this research to obtain more potent alpha-/beta-adrenoceptor blocking and long-acting antihypertensive oxypropanolamine on the 4-phenyl ring of dihydropyridine series compounds was thus accomplished and classified as third generation dihydropyridine type calcium channel blockers, in comparison with previous short-acting type nifedipine and long-acting type amlodipine. We concluded that compounds 1a, 1b and 1g showed not only markedly high calcium-antagonistic activity but also the highest antihypertensive effect; compounds 1b, 1c, 1f, 1g, 1i and 1j induced sustained antihypertensive effects are major and attributed to their calcium entry and alpha-adrenoceptor blocking activities in the blood vessel due to their introduction of 2-methoxy, 1-oxyethylamino benzene moiety in the side chain on the 4-phenyl ring of dihydropyridine. Bradycardiac effects of all the compounds 1a-1j resulted from calcium entry and beta-adrenoceptor blocking, which attenuate the sympathetic activation-associated reflex tachycardia in the heart. We selected compound 1b as candidate compound for further pharmacological and pre-clinical evaluation studies.
Liang
Jhy-Chong
JC
Department of Pharmacology, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan, ROC.
Yeh
Jwu-Lai
JL
Wang
Chia-Sui
CS
Liou
Shwu-Fen
SF
Tsai
Chieh-Ho
CH
Chen
Ing-Jun
IJ
D018674:Adrenergic Antagonists / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D000959:Antihypertensive Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D001011:Aorta / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D004095:Dihydropyridines / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D004333:Drug Administration Routes; D006339:Heart Rate / Q000187:drug effects; D009200:Myocardial Contraction / Q000187:drug effects; D010665:Phenylpropanolamine / Q000737:chemistry; D051381:Rats; D017208:Rats, Wistar; D013329:Structure-Activity Relationship
D018674:Adrenergic Antagonists; D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; D004095:Dihydropyridines; D010665:Phenylpropanolamine