New antithrombotic 1-Phthalazinamines with Serotonin Antagonistic Properties

Facile Synthesis, Characterization, and Antimicrobial Evaluation of Novel Heterocycles, Schiff Bases, and N-Nucleosides Bearing Phthalazine Moiety

The present work describes convenient synthesis of the novel Schiff bases 5a and b by reacting phthalazinones 4a and b with 4-methoxybenzaldehyde Reaction of the Schiff bases with phenylisothiocyanate afforded diazetidine derivatives 7a and b. Also, compounds 4a and b reacted with 2-bromoglucoside tetraacetate giving peracetylated N-glycosides 6a and b, which were deacetylated to afford N-glycosylated phthalazinones 8a and b. On the other hand, when compound 3 was treated with POCl3/PCl5 and/or ethyl chloroacetate, chlorophthalazine and ethyl acetate derivatives 9 and 10 were obtained, respectively. Hydrazinolysis of compounds 9 and 10 produced the hydrazino and hydrazide derivatives 11 and 12, respectively. When compound 11 reacted with 2-furanaldehyde, acetic anhydride, and/or carbon disulphide, it gave compounds 13-15, respectively. Treatment of the hydrazide 12 with aromatic aldehydes, acetic anhydride, ethyl acetoacetate, acetyl acetone, ammonium thiocyanate, and/or phthalic anhydride furnished compounds 17-21. Meanwhile, reacting Schiff base 22 with the chlorophthalazine derivative 9 produced compound 23, which on treatment with furoyl chloride produced compound 24. The structures of the novel compounds were confirmed by IR, (1)H-NMR, (13)C-NMR, MS, and elemental analysis. The newly synthesized compounds were tested against Bacillus subtilis and Staphylococcus aureus as Gram-positive bacteria, Escherichia coli and Pseudomonas aurignosa as Gram-negative bacteria, and Candida albicans and Aspergillus niger as fungi strains. Compounds 5a and b, 23, and 24 showed greater antimicrobial activity than the stranded compounds, suggesting that they could be considered as promising antimicrobial agents.

New 1H-pyrazole-4-carboxamides with antiplatelet activity

Nine title compounds were synthesized and investigated in the Born test for their antiplatelet activities against collagen, ADP, adrenaline, and platelet activating factor (PAF) as inducers of the aggregation. Using collagen three compounds with IC50 values below 100 microM were found (3b, 3e, 3i). Activities in nanomolar concentrations were observed against ADP (3b, IC50 = 9.4 nM), adrenaline (3i, IC50 = 5.8 nM), and platelet activating factor (3e, IC50 = 0.45 nM).

New Purines with Antiplatelet Activity

Four purine-2,6-diamines, 4a, b, 5a, b, nineteen N-(purin-2-yl)benzenecarboxamides 6a-q, 7b, and one N-(purin-2-yl)-2-furanecarboxamide 8 were prepared for the first time and tested for their inhibition of blood platelet aggregation. Six compounds, 6a, b, h, m, o, p, inhibited the platelet aggregation induced by collagen with IC(50 )values between 3 and 10 micromol/L in the Born test. ADP, PAF, and adrenaline were used as specific aggregation inducers to examine the mechanism of the anti-aggregating activity. An astonishing pattern of activities in the nanomolar, with 6m, 7b, 8 and even subnanomolar range, with 6b, was observed. Compound 6b inhibited the platelet aggregation induced by ADP with an IC(50) = 0.45 nM (6m: 3.5 nM; 8: 30 nM). Compound 7b showed an antagonism against the inducer adrenaline with an IC(50) = 1.8 nM (6o: 20 nM; 8: 30 nM). The strongest antagonism against PAF was observed with 7b showing an IC(50) = 1 nM (6b: 35 nM; 8: 74 nM).