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Unprecedented domino oxidative cyclization reactions of unprotected 2-alkynylanilines to give functionalized 4H-benzo[d][1,3]oxazin-4-one or benzisoxazole derivatives in moderate to good yields are achieved by silver vs. gold selective catalysis. The search for the optimal reaction conditions revealed the divergent catalytic activity of NaAuCl4·H2O and AgNO3.

Title compounds are obtained mostly in high yields in the presence of the stable gold catalyst GAB avoiding a silver co-catalyst.

Preliminary results of sequential alkylation/gold-catalyzed annulation reactions of anilines with propargylic bromide derivatives to provide quinoline scaffolds are described. The efficiency of NaAuCl4·2H2O in the sequential procedure was investigated and compared with different transition metal salts and Au(I) complexes. Selectivity of the reaction of aniline derivatives with propargylic bromides has also been investigated.

A series of xanthone 1,4-dihydropyridine derivatives were prepared. The compounds were evaluated for inotropic, chronotropic and calcium antagonistic properties. The tested compounds are weak calcium antagonists but exert potent selective bradycardic effects.

A series of 4-heterotricyclic substituted 1, 4-dihydropyridines were prepared. The compounds were evaluated for inotropic, chronotropic and calcium antagonist properties. The tested compounds are fairly good as calcium antagonists, but exert potent selective bradycardic effects

A new series of 4-(nitrogenous heteroaryl)-1,4-dihydropyridine antagonists II - XVI were synthesized and screened for inotropic, chronotropic and calcium antagonist properties, in order to evaluate the effect on pharmacological activity of replacement of the 4-aryl group of nifedipine-like drugs by heterocyclic moieties, such as quinoline, indole, carbazole and pyrazole. The most potent bradycardic compounds of the series ( VIII - X , XII and XIII ) elicited weak calcium antagonist activity and were stronger negative inotropic.

The xanthone analogues of milrinone have been prepared. The new compounds do not retain the inotropic activity of the parent compound.

A series of fluorenone and benzophenone 1,4-dihydropyridine derivatives were prepared. The compounds were evaluated for inotropic, chronotropic and calcium antagonist properties.

The synthesis and the pharmacological characterization of novel heterocyclic systems 1 and 2 is described. On radioreceptor assay 1a showed higher affinity for Calcium Channel Receptors (CCRs) and in functional studies higher potency and efficacy as negative inotropic agent than Diltiazem, without relevant calcium antagonist activity on vascular smooth muscle, revealing a clear-cut selectivity for cardiac over vascular tissue.

A series of some benzazepinone derivatives were prepared. The compounds were evaluated for inotropic, chronotropic and calcium antagonist properties. For the compounds bearing well-known alpha-blocking fragments, the antagonist potency at postsynaptic alpha-adrenoceptors was assessed. The new compounds were less effective as bradycardic agents and calcium antagonists but show remarkable negative inotropic activity.

A series of xanthone and fluorenone-1,4-dihydropyridine derivatives bearing a 5-phosphonate group were prepared. The compounds were evaluated for inotropic, chronotropic and calcium antagonistic properties. The insertion of a phosphonate group is detrimental for inotropic and calcium antagonistic activity but improves the potency and selectivity for chronotropism.

A series of xanthone-1,4-dihydrophyridine derivatives bearing a chlorine atom in the xanthone nucleus was prepared. The compounds were evaluated for inotropic, chronotropic and calcium antagonist properties. The chlorine introduction in the xanthone moiety slightly affected affinity for cardiac vs. vascular tissues improving to some extent selectivity.

[reaction: see text] The palladium-catalyzed arylation of the alpha-methylene-gamma-butyrolactone proceeds in good yields and may be directed toward the synthesis of 3-benzylfuran-2(5H)-ones when the starting aryl iodides contain strongly electron-withdrawing groups. The combined palladium-catalyzed arylation/hydrogenation of the alpha-methylene-gamma-butyrolactone represents a new simple entry into functionalized alpha-benzyl-gamma-butyrolactones.

The hydroarylation of 3-arylprop-2-yn-1-amine derivatives with arylboronic acids has been studied in the presence of rhodium or palladium catalysts. By using a rhodium-based catalytic system, β,γ-diarylallylamines were isolated in good yields. By contrast, the formation of the regiosomeric γ,γ-diarylallylamines was achieved by means of a palladium catalyst in the presence of acetic acid. The complementary regioselectivity displayed by these two processes is a consequence of different catalytic cycles, involving respectively carborhodation or hydropalladation of the coordinated alkyne as key steps. Calculated charge distributions in the π-complexes are in accord with the results obtained.

The selective synthesis of (Z)- or (E)-3-aryl/vinyl/alkylidene-isoindolones, and 2-benzopyran derivatives from o-(1-alkynyl)benzamides by means of a suitable choice of bases or silver catalysis is described.

A convenient synthetic method for the pharmaceutically important 6-substituted-4,5-dihydro-3(2H)-pyridazinones is described. The synthetic strategy is based on Δ 2 -isoxazolines chemistry which were in turn unmasked by N-O bond cleavage and cyclized to the target compounds