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A number of 4-dialkylamino-1-(5-substituted or unsubstituted 1-phenyl-1H-pyrazol-4-yl)butan-1-ols 2a-n were synthesized and tested in vivo for anti-inflammatory and analgesic activities and in vitro for platelet anti-aggregating activity. Dimethylaminoderivatives 2b, e, g showed good analgesic activity; almost all of them had strong platelet anti-aggregating properties at a final concentration of 1 x 10(-3) M; pyrazoles 2c, d, f-h showed weak anti-inflammatory activity.

The synthesis of ethyl esters of 5-cyano-1,6-dihydro-6-oxo-3-pyridinecarboxylic acids carrying as 2-substituent the 2-,3- or 4-pyridyl group is described. By alkaline hydrolysis followed by acidification, these esters gave the corresponding carboxylic acids, which were decarboxylated to 1,2-dihydro-2-oxo-6-(2,3,4-pyridyl)-3-pyridinecarbonitriles. As milrinone analogues, the above compounds were tested on contractile activity and frequency rate of spontaneously beating atria from reserpine-treated guinea-pigs. Ethyl 5-cyano-1,6-dihydro-6-oxo-2-(2-pyridyl)-3-pyridinecarboxylate showed an appreciable positive inotropic activity, although inferior to that of milrinone; moreover, some other compounds bearing the above 2-substitution pattern showed interesting antiinflammatory, analgesic and hypotensive activity.

Reaction of methyl 4-methoxy-2-dimethylaminomethylene-3-oxobutanoate with arylhydrazines gave methyl 1-aryl-5-(methoxymethyl)-1H-pyrazole-4-carboxylates 1 in high yields. Esters 1 were hydrolyzed to the relative carboxylic acids, which were converted by heating to 1-aryl-5-(methoxymethyl)-1H-pyrazoles 3 in good yields. Reaction of 3 with hydrobromic acid afforded the intermediate 1-aryl-5-(bromomethyl)-1H-pyrazoles, which were converted with potassium cyanide to 1-aryl-1H-pyrazole-5- acetonitriles, whose hydrolysis gave the required 1-aryl-1H-pyrazole-5-acetic acids. Some acids 5 showed a strong antiinflammatory and analgesic activity in rats and mice, respectively, as well as moderate antipyretic and in vito platelet antiaggregating effects.

The synthesis of a series of N-substituted 4-carboxy-1-phenyl-1H-pyrazole-5-propanamides by reaction of 1-phenyl-1H-oxepino[4,3-c]pyrazole-4(8H),6(7H)-dione with aromatic primary amines is described. Some amides showed a platelet antiaggregating activity in vitro superior or comparable to that of acetylsalicylic acid, as well as moderate antiinflammatory, analgesic and antipyretic activities in rats or mice.

The synthesis of a series of 1-aryl-1,6-dihydro-4H-thieno[3,4-c]pyrazol-4-ones by cyclization of 3-[(2-arylhydrazino)methylene]thiophene-2,4(3H,5H)-diones, prepared by reacting 3-dimethylaminomethylenethiophene-2,4(3H,5H)-dione with arylhydrazines, is described. The 4-fluorophenyl derivative showed remarkable analgesic, antiinflammatory and antipyretic activities in mice or rats, as well as a platelet antiaggregating activity in vitro comparable to that of acetylsalicylic acid.

The synthesis of [(1-methyl-1H-indazol-4-yl)oxy]acetic acid 4, 1-methyl-1H-indazole-4-acetic acid 9, 2-(1-methyl-1H-indazol-4-yl)propanoic acid 15 and [[(1,5,6,7-tetrahydro-1-methyl-4H-indazol-4-ylidene)amino]oxy]acet ic acid 16, as well as of amides and esters derived from 4 and 9, starting from 1,5,6,7-tetrahydro-1-methyl-4H-indazol-4-one is described. Some of the above compounds showed weak antiinflammatory, analgesic, antipyretic and hypotensive activities in rats and mice, as well as moderate platelet antiaggregating effects in vitro.

The synthesis of 4-hydroxy-1-phenyl-1H-indazole-5-acetic acid 5 4-methoxy-1-phenyl-1H-indazole-5-yl-acetic acid 7 and 5-benzyl-1-phenyl-1H-indazol-4-ol 8, starting from 1,5,6,7-tetrahydro-1-phenyl-4H-indazol-4-one, is described. These compounds showed in mice an analgesic activity superior to that of acetylsalicylic acid and comparable to that of dipyrone; moreover, compound 5 exhibited an appreciable anti-inflammatory activity in rats. Grossbehavioral effects and acute toxicity in mice are also reported.

The synthesis of amides 3 and 4 starting from (1-phenyl-1H-indazol-4-yl)acetic and [(1-phenyl-1H-indazol-4-yl)oxy]acetic acids, respectively, as well as of 2-(1-phenyl-1H-indazol-4-yl)ethanamines 5 starting from 3, is described. Moreover, a number of 2-[(1-phenyl-1H-indazol-4-yl)oxy]ethanamines 7 and 3-[(1-phenyl-1H-indazol-4-yl)oxy]propanamines 8 were prepared starting from 1-phenyl-1H-indazol-4-ol. Some compounds 3, 4 and 7 showed an appreciable analgesic activity in mice, whereas compounds 4 were moderately active as antiinflammatory agents in rats. Some compounds 3, 4, 5, 7 and 8 showed also local anesthetic and a weak antipyretic activity in mice and rats, respectively.

Reaction of ethyl or methyl 2-dimethylaminomethylene-3-oxoalkanoates 2 with phenylhydrazine gave the corresponding esters of 5-substituted 1-phenyl-1H-pyrazole-4-carboxylic acids 3 in high yields. Esters 3 were hydrolyzed to the relative carboxylic acids 4, which were converted by heating to 5-substituted 1-phenyl-1H-pyrazoles 5 in excellent yields. Reaction of methyl 5,5-dimethyl-3-dimethylaminomethylene-2,4-dioxohexanoate with phenylhydrazine afforded methyl 1-phenyl-4-pivaloyl-1H-pyrazole-5-carboxylate 8 b, which was converted as above to the corresponding carboxylic acid 10 b and this to 1-phenyl-4-pivaloyl-1H-pyrazole 11 b. Starting from 5-methoxymethyl-1-phenyl-1H-pyrazole, 1-phenyl-1H-pyrazole-5-acetic acid 18 and its alpha-methyl derivative 19 were also synthesized. Compounds 18, 19, 10 b and 11 b showed a strong antiinflammatory activity in rats; the same compounds in general as well as 8 b, showed appreciable analgesic and antipyretic activities in mice and rats, respectively.

The synthesis of [(1-phenyl-1H-indazol-4-yl)oxy]acetic acid (IV), (1-phenyl-1H-indazol-4-yl)acetic acid (IX) and (1,5,6,7)tetrahydro-1-phenyl-4H-indazol-4-iminooxy)acetic acid (XIII) starting from 1,5,6,7-tetrahydro-1-phenyl-4H-indazol-4-one (I) is described. These compounds showed a good antiinflammatory activity in rats, and an analgesic activity in mice similar or comparable to that of indomethacin.

The synthesis of 1-phenyl- and 1-methyl-5-dialkylamino-methyl-1,5,6,7-tetrahydroindazol-4-ones (III) and (IV) by Mannich reaction of the corresponding 1-substituted 1,5,6,7-tetrahydroindazol-4-ones (I) and (II) is described. Some compounds (III) showed a good antiinflammatory and analgesic activity in rats and mice, respectively. Infiltration anesthesia in mice and antiacetylcholine activity in vitro are also reported.