Claudio Mori

Synthesis and β-blocking activity of (R, S)-(E)-oximeethers of 2,3-dihydro-1,8-naphthyridine and 2,3-dihydrothiopyrano[2,3-b]pyridine : potential antihypertensive agents - Part IX

The synthesis of oximeethers of 2,3-dihydro-1,8-naphthyridine and 2, 3-dihydrothiopyrano[2,3-b]pyridine is described. These compounds exhibit a selective beta-blocking activity, with a selectivity towards beta(2)-receptors. Groups in the N(1) position giving rise to a considerable steric hindrance led to a higher beta(2)-blocking selectivity, whereas groups creating a moderate hindrance caused a weak but significant decrease in beta(2)-antagonist potency. Substitution of the N(1)-R group with a sulfur atom led to compounds possessing beta(1)-, beta(2)- and beta(3)-blocking properties. Compounds 9c(1) and 10a(1) showed a beta(3)-antagonist activity slightly lower than that of propranolol.

Synthesis of 1,8-naphthyridine derivatives: potential antihypertensive agents – Part VIII

A series of 2-(carbethoxypiperazinyl)- and 2-piperazinyl-1,8-naphthyridine derivatives, variously substituted, have been synthesized and pharmacologically investigated for their antihypertensive activity. Some of them exhibited a significant and prolonged decrease of the mean arterial pressure (MAP) on spontaneously hypertensive rats. For this series of compounds, on the basis of the pharmacological results obtained, no structure-activity relationship can be deduced at this time. Moreover, the most active and representative compounds 11b, 12a and 16b were investigated by means of in vitro pharmacological functional studies and in vivo, as diuretic agents, to determine a possible mechanism of the antihypertensive activity, which is unknown for the moment.

Synthesis and evaluation of antimycobacterial activity of 4-phenyl-1,8-naphthyridine derivatives.

Some 4-phenyl-1,8-naphthyridine derivatives with a piperazino group in the 2- and/or 7-position have been synthesized and evaluated for their tuberculostatic activity. The compounds 1, 6, 10, 17b,c and 19i showed a marked activity against Mycobacterium tuberculosis H37Rv. For this series of compounds, submitted to biological screening, no structure-activity relationship can be deduced.

Use of β-cyclodextrin in the capillary zone electrophoretic separation of the components of clandestine heroin preparations

The present paper describes the methodological optimization and validation of a capillary zone electrophoresis method for the rapid determination of heroin, secondary products and additives present in clandestine heroin samples, by using 20 mM beta-cyclodextrins in phosphate buffer, pH 3.23. Applied potential was 15 kV and separation temperature was 24 degrees C; detection was by UV absorption at 200 nm wavelength. Heroin samples were first dissolved in CHCl3-MeOH (96:4, v/v) and injected by pressure (0.5 p.s.i., 3 s; 1 p.s.i.=6894.76 Pa) after evaporation of the organic mixture and reconstitution in aqueous buffer. Under the described conditions, phenylethylamine (internal standard), morphine, monoacetylmorphine, heroin, acetylcodeine, papaverine, codeine and narcotine were baseline resolved in less than 10 min. The limit of detection was better than 1 microg/ml for each analyte. The study of the intra-day and day-to-day precision showed, in terms of migration times, RSDs < or = 0.71% and, in terms of peak areas, RSDs < or = 3.2%. Also, the evaluation of linearity and analytical accuracy of the method provided good results for all the analytes investigated, thus allowing its application to real cases of seized controlled drug preparations.

Synthesis and β-blocking activity of (E)- and (Z)-iminoethers of 1,8-naphthyridine. Potential antihypertensive agents. 4

Abstract A series of substituted (E)-and (Z)-iminoethers of 1,8-naphthyridine was synthesized from corresponding ketones. The pharmacological activity of these compounds was evaluated on isolated preparations to assess the eventual interaction with α and β adrenoceptors. All the compounds exhibited β2 stimulating and β1 blocking properties, while on α receptors neither stimulating nor blocking activity was observed.

Synthesis and antiplatelet activity of some 2,7-di(N-cycloamino)-3-phenyl-1,8-naphthyridine derivatives

Several 2,7-di(N-cycloamino)-3-phenyl-1,8-naphthyridine derivatives were synthesized and tested for their ability to inhibit human platelet aggregation in vitro induced by arachidonic acid, collagen and ADP. Only five compounds showed any appreciable activity, and the results of all the active derivatives were similar to those of papaverine in the test with arachidonic acid and collagen. Moreover, the most active compounds were investigated in the test with ADP and again showed a significant activity. The tested compounds that possessed the best activity were also shown to increase the c-AMP level significantly without involving the adenylyl cyclase system.

Synthesis and evaluation of antihypertensive activity of 1,8-naphthyridine derivatives. Part X

A series of 4-(N-methylencycloalkylamino)-1,8-naphthyridine derivatives variously substituted in positions 2 and 7 were synthesized and pharmacologically investigated for possible antihypertensive activity. These compounds were tested to determine a possible vasodilator mechanism of action. Compounds 22, 23, 27-29, 47 and 48 showed satisfactory levels of potency (pIC(50)>5), which in one case (compound 23) reached a really interesting value (pIC(50) 6.92). Furthermore, for some selected compounds (19, 22, 23, 26, 28, 29, 47), the vasorelaxing activity was also evaluated in the presence of the guanylate cyclase blocker ODQ or of the adenylate cyclase blocker SQ 22536, and some of these can be considered as possible guanylate-cyclase inhibitors. Finally, compounds 19, 22 and 23 were also tested in the presence of the ATP-sensitive potassium channel blocker glybenclamide and seem to possess activating properties on these potassium channels.

Synthesis of variously substituted 1,8-naphthyridine derivatives and evaluation of their antimycobacterial activity.

A series of 1,8-naphthyridine derivatives variously substituted in the 2, 3, 4 and 7 positions were synthesized for in vitro evaluation of antimycobacterial activity in accordance with an international program with the tuberculosis antimicrobial acquisition and coordinating facility (TAACF). Several compounds 4, 8, 12, 14, 19, 29 and 30, when tested at a concentration of 6.25 microg/ml against Mycobacterium tuberculosis H37Rv, showed an interesting activity with % inhibition in the range 38-96%. The most effective substituent in position 2, 4 or 7 of the 1,8-naphthyridine nucleus seem to be the piperidinyl group.

Synthesis and antiplatelet activity of some 3-phenyl-1,8-naphthyridine derivatives.

A series of 2-cycloalkylamino-3-phenyl-1,8-naphthyridine derivatives, variously substituted in the 6- and 7-positions were synthesized and tested for their ability to inhibit human platelet aggregation in vitro induced by arachidonate, collagen and ADP. Compounds 5a,b, 7a,b, 8a and 10c,d showed a remarkable activity similar to that of indomethacin in the test with arachidonate and collagen. In the test with ADP only compound 8a showed a significant activity. The presence of a morpholinyl or piperidinyl group in position 2 and of a chloro or methoxy group in position 7 of the 1,8-naphthyridine nucleus seem to favour a higher activity. However on the basis of the pharmacological results, no structure-activity relationship can be deduced. Compounds 5b and 7b, which possess the best activity in the arachidonate test, were also shown to increase the c-AMP level significantly, without involving the adenylyl cyclase system.

Synthesis and antiplatelet activity of some 1,8-naphthyridine derivatives

Abstract A series of 1,8-naphthyridine derivatives was synthesized and tested for their ability to inhibit human platelet aggregation in vitro induced by arachidonic acid, collagen and ADP. Some compounds showed remarkable activity and the most active derivatives were comparable to papaverine in the test with arachidonic acid and collagen. In the test with ADP the tested compounds showed no significant activity. The tested compounds that possessed the best activity were also demonstrated to increase the c-AMP level significantly without involving the adenylyl cyclase system.