Rahime Simsek

Fused 1,4-Dihydropyridines as Potential Calcium Modulatory Compounds

1,4-Dihydropyridine (1,4-DHP) derivatives nifedipine of which the prototype, are the most popular drugs having calcium antagonistic activity. Fused 1,4-dihydropyridines (DHPs) have also exhibit calcium modulatory activities. In this article, we emphasize calcium channels and fused 1,4-DHP derivatives affecting calcium channels. In addition, the basic considerations of synthesis, metabolism, structure-activity relationships and the latest developments on fused 1,4-DHP derivatives will be reviewed. This review also has extended examples of fused 1,4-DHP derivatives having cited activities synthesized by our group.

Relaxant effects of some benzothiazolinone derivatives on isolated rabbit corpus cavernosum.

Abstract In the present study, two 6-(fluorobenzoyl)-3-piperazinomethyl-2-benzothiazolinone derivatives were synthesized and their relaxant effects on isolated rabbit corpus cavernosum investigated. Compounds Y-16 and Y-21 can alter the ability of corpus cavernosum smooth muscle to contract. Strips of rabbit corpus cavernosum smooth muscle were mounted in isolated tissue baths for measurement of isometric contractile force. Compounds (10−6–10−3 M) did not cause contraction but induced relaxation in precontracted corpus cavernosum smooth muscle. Neither N-nitro-l-arginine methylester (L-NAME) nor indomethacin affected the relaxant effect of these compounds. Glibenclamide and tetraethylammonium chloride (TEA) also did not influence the relaxation induced by the compounds. In conclusion, in isolated rabbit corpus cavenosum, Y16 and Y21 have a relaxant potency equal or superior to known vasoactive agents. Further investigations are needed to show the importance of these effects for the diagnosis and treatment of erectile dysfunction.

Cocrystals of diastereoisomers of 1,4-dihydropyridine derivatives.

A mixture of the RR/SS and RS/SR diastereoisomeric pairs of methyl 4-(2,4-dichlorophenyl)-2,7-dimethyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate, C 19 H 19 Cl 2 NO 3 , forms cocrystals in which there is one unique molecule in the asymmetric unit, but the molecule displays disorder in the region of the 7-position of the quinoline ring system as a result of the random occurrence of the diastereoisomers at the same crystallographic site. A similar arrangement exists in the monohydrate cocrystals that form from a mixture of the RRI SS and RS/SR diastereoisomeric pairs of methyl 4-(2,4-dichlorophenyl)-2-methyl-7-phenyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate monohydrate, C 24 H 21 Cl 2 NO 3 ·-H 2 O. These compounds belong to a class of 1,4-dihydropyridines whose members have calcium modulatory properties. The 1,4-dihydropyridine rings have the usual shallow boat conformation. In each structure, the 2,4-dichlorophenyl ring is oriented such that the 2-chloro substituent is in a synperiplanar orientation with respect to the 1,4-dihydropyridine ring plane. In each crystal structure, the molecules are linked into chains by N-H···O hydrogen-bonding interactions.

Photochemical study of hexahydroquinoline derivatives--a new group of calcium antagonists.

The photochemical stability of 2, 6, 6‐trimethyl‐3‐carbmethoxy‐4‐phenyl‐5‐oxo‐1, 4, 5, 6, 7, 8‐hexahydroquinoline (HHQ) derivatives with different substituents on the phenyl ring (—Cl, —NO2, —CF3, —CH3, —OCH3) has been studied.The process of photodegradation was studied by UV spectrophotometry. The rate of photodegradation was found to depend on the type and position of the substituent in the phenyl ring. The compounds most susceptible to the damaging effect of light proved to be those containing the nitro group, in particular with the substituent in the ortho position of the aromatic ring. Derivatives with alkyl (—CH3) and halo‐alkyl (—CF3) substituents showed the greatest photochemical stability. The compounds with substituents in the ortho position were found to be much less photostable than the meta isomers. The quantum yield values obtained ranged from 10−4 to 10−3, indicating the occurrence of secondary photochemical processes initiated by the primary products of decomposition.

Synthesis of 2-Methyl-4-aryl-4,6,7,8-tetrahydro-5(1H)-quinolone Derivatives and their Effects on Potassium Channels

In this study, twelve compounds having 2-methyl-4-aryl-4,6,7,8-tetrahydro-5(1H)-quinolone structure have been synthesized by the reaction of 4-aryl-3-butene-2-on derivatives with 1,3-cyclohexanedione analogs in the presence of ammonium acetate in methanol. The structures of the compounds have been elucidated by IR, 1H-NMR, 13C-NMR, mass spectroscopy and elementel analysis. Their potassium channel opener activities have been investigated on isolated rabbit bladder smooth muscle using pinacidil (CAS 85371-64-8) as standard. The test compounds and pinacidil caused concentration-dependent relaxation responses in bladder smooth muscle strips precontracted with 80 mmol/L KCl with the efficacy order: pinacidil > or = 3g > or = 3j > or = 3a > or = 3l = 3i > or = 3c = 3b > or = 3d > or = 3h > or = 3k. In bladder smooth muscle strips precontracted with 15 mmol/L KCl, the efficacy order was: pinacidil > 3h > or = 3c > or = 3j > or = 3g > or = 3l > or = 3i = 3b > or = 3k > or = 3f > or = 3a. The test compounds and pinacidil caused concentration-dependent inhibition of electrical field stimulation-evoked contractile responses in the bladder smooth muscle strips with the efficacy order: 3j > or = 3l pinacidil > or = 3k > or = 3h > or = 3a > or = 3g > or = 3c > or = 3i > or = 3b > or = 3f.

Synthesis of fused 1,4-dihydropyridines as potential calcium channel blockers

Abstract Objective The aim of this study was to synthesize ten 1,4-dihydropyridine (DHP) derivatives in which substituted cyclohexane rings were fused to the DHP ring and to determine how different ester groups and the benzoyl substituent introduced in 4-phenyl ring affected their calcium channel blocking activity. Methods A microwave-assisted one-pot method was applied for the synthesis of compound 1–5 according to a modified Hantzsch reaction. The benzoyl moiety was introduced in the 4-phenyl ring of these dihydropyridines by refluxing with benzoyl chloride in acetone in the presence of anhydrous potassium carbonate. Synthesized products were characterized by elemental analysis, IR, 1H-NMR and 13C-NMR spectroscopy. The inhibitory actions of compounds 1–10 on calcium channel blocking activity were tested on isolated rat aorta preparations. Results The obtained pharmacological results showed that although all compounds are potent relaxing agents on isolated rat aorta smooth muscle, introduction of a benzoyloxy substitiuent on the phenyl ring (compound 6–10) decreased the relaxant effect of these compunds. Conclusion The reported 1,4-DHP derivatives have calcium channel blocking activity on rat aorta smooth muscle.