Synthesis and structure-activity relationships of 1-substituted 4-(1,2-diphenylethyl)piperazine derivatives having narcotic agonist and antagonist activity

Racemates and enantiomers of 1-substituted 4-[2-(3-hydroxyphenyl)-1-phenylethyl]piperazine derivatives (3-18) were synthesized, and their analgesic and other pharmacological activities and structure-activity relationships were investigated. The S-(+) enantiomers of 2a, 5, 7, 9, 10, and 15-18 had a stronger analgesic activity than their R-(-) enantiomers; analgesic activity of the strongest one [(S)-(+)-10] was 105 times as potent as that of morphine. The S-(+) enantiomers of these compounds had the opposite configuration to that of morphine with respect to its (C-9) asymmetric center but the same configuration to that of the tyrosine residue of Met5-enkephalin. The R-(-) enantiomers of 16 and 18 showed narcotic antagonist activity, but the S-(+) enantiomers did not. (R)-(-)-18 had analgesic and narcotic antagonist activities comparable to pentazocine but showed no significant physical dependence liability. From these results, it is suggested that these compounds show an uncommon enantioselectivity in comparison with morphine and its surrogates, and belong to a new series of compounds having a potent analgesic activity.     

Studies on 3-substituted 1,2-benzisoxazole derivatives. 6. Syntheses of 3-(sulfamoylmethyl)-1,2-benzisoxazole derivatives and their anticonvulsant activities.

Several 3-(sulfamoylmethyl)-1,2-benzisoxazole derivatives were synthesized from 3-(bromomethyl)-1,2-benzisoxazole by the reaction with sodium bisulfite followed by chlorination and amination. Some of them displayed marked anticonvulsant activity in mice. The introduction of a halogen atom to the 5 position of the benzisoxazole ring caused increased activity and neurotoxicity; the substitution of a sulfamoyl group caused decreased activity. The activity of monoalkylated compounds might be the result of biotransformation. Among these compounds, 3-(sulfamoylmethyl)-1,2-benzisoxazole (1a) was thought to be the most promising as an anticonvulsant from the ratio of NTD50 and ED50.     

Studies on analgesic agents. 1.1a Preparation of 1,2-diphenyl-2-(4-substituted 1-piperazinyl)ethanol derivatives and structure-activity relationships.

The preparation and analgesic activity of a series of the title compounds (8-55 and 57) are described. The intermediates, 2-phenyl-2-(1-piperazinyl)acetophenones 5 and 6, were prepared from benzyl phenyl ketones 3 via their bromides 4. On reduction, compounds 5 afforded the titled compounds 8-12, 16, and 26-48. Compounds 13-15 and 17-25 were obtained by alkylation or benzylation of 1.2-diphenyl-2-(1-piperazinyl)ethanols 7 derived from 6 by reduction. The reduction of 5 and 6 with metal hydrides predominantly gave the erythro isomers. The erythro isomers were remarkably more active than their threo isomers. The more active members in this series of compounds were 16 and derivatives 35 and 37-44 of dl-erythro-1-phenyl-2-(substituted phenyl)-2-[4-(p-methoxybenzyl)-1-piperazinyl]ethanol. Compounds 16, 43, and 44 were the most active with a potency of about two to three times that of codeine. Racemates 16 and 38 were resolved into their optical isomers and it was found that (-)-16 and (+)-38 were more potent than their antipodes. Structure-activity relationship are discussed.     

3,5-Diphenyl-1H-pyrazole derivatives. II--N-substituted 1-(2-aminoethyl)-3,5-diphenyl-1H-pyrazoles and their 4-bromo derivatives with analgesic and other activities

The synthesis of N-substituted 1-(2-aminoethyl)-3,5-diphenyl-1H-pyrazoles and their 4-bromo derivatives (V) by reaction of primary and secondary amines with the tosylates of 1-(2-hydroxyethyl)-3,5-diphenyl-1H-pyrazole and its 4-bromo derivative is described. Some of compounds (V) showed a remarkable analgesic activity in mice. Moreover, the above compounds usually exhibited moderate hypotensive, bradycardiac and antiinflammatory activities in rats, infiltration anesthesia in mice, as well as a weak platelet antiaggregating activity in vitro.     

四氢喹啉类化合物的合成及其镇痛活性研究

目的寻找具有镇痛活性的新型四氢喹啉类化合物,探讨4-（1H-吡咯-2-基）-1,2,3,4-四氢喹啉类化合物镇痛作用的构效关系。方法以4-（1H-吡咯-2-基）-1,2,3,4-四氢喹啉类化合物为母体,合成系列化合物。用醋酸致小鼠扭体法测定该类化合物的镇痛活性。结果与结论合成了20个新化合物,经1H-NMR和MS确证其结构。镇痛活性试验表明,所合成的部分化合物具有明显的镇痛作用,值得进一步研究。     

4-substituted 1-methyl-1H-indazoles with analgesic, antiinflammatory and antipyretic activities.

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.     

Synthesis of N-[4-(alkyl)cyclohexyl]-substituted benzamides with anti-inflammatory and analgesic activities.

Two series of N-[4-(alkyl)cyclohexyl]-substituted benzamides, i.e. a series of N-[4-(tert-butyl)cyclohexyl]-substituted benzamides and a series of N-[4-(ethyl)cyclohexyl]-substituted benzamides, were synthesised and evaluated for their anti-inflammatory and analgesic potencies, and gastrointestinal irritation liability.     

Synthesis of 4(1H)-pyridinone derivatives and investigation of analgesic and antiinflammatory activities.

This paper describes recent results of a research program aimed at the synthesis and pharmacological evaluation of new 4(1H)-pyridinone derivatives belonging to the 1,3-disubstituted series (4-11). These compounds were structurally planned by applying the molecular hybridization strategy on previously described 1,2-disubstituted-4(1H)-pyridinone derivatives, considered as lead compounds, which present potent analgesic properties (M.D. Aytemir, T. Uzbay, D.D. Erol, Arzneim. Forsch. (Drug Res.) 49 (1999) 250). Their chemical structures have been proved by means of their IR and 1H NMR data and by elemental analysis. The analgesic profile of the title compounds (4-11), evaluated by the model of abdominal constrictions induced by acetic acid, showed that all the 4(1H)-pyridinone derivatives were active, exhibiting an analgesic activity comparable with that of aspirin (acetyl salicylic acid) used as a standard. The antiinflammatory profile of the synthesized compounds, evaluated by the model of carrageenan rat paw edema, showed that all compounds were active and were comparable with indomethacin used as a standard.     

Synthesis and analgesic activities of some (4-substituted phenyl-1-piperazinyl)alkyl 2-aminobenzoates and 2-aminonicotinates.

A series of (4-substituted phenyl-1-piperazinyl)alkyl 2-aminobenzoates and 2-aminonicotinates has been prepared and screened for analgesic and antiinflammatory properties in mice and rats. The tabulated results reveal several 2-(4-substituted phenyl-1-piperazinyl)ethyl 2-(7- or 8-substituted 4-quinolinylamino)benzoates to be six to nine times more potent analgesics than the reference compounds (glafenine and aminopyrine) and to possess minor antinflammatory activity. Compound 45, 2-[4-[3-(trifluoromethyl)phenyl]-1-piperazinyl]ethyl 2-[[7-(trifluoromethyl)-4-quinolinyl]amino]benzoate (antrafenine), showed marked analgesic activity, long duration of action, and excellent tolerance in pharmacological and toxicological studies, as well as in clinical trials.     

The synthesis of 1,2-benzothiazine-3-carboxamidylhydantoin derivatives and their antiinflammatory and analgesic activities

A number of 4-hydroxy-2H (or alkyl)-N-(3-aralkyl-2-thio-1-hydantoinyl)-1,2-benzothiazine-3-carboxamide 1,1-dioxides were synthesized through the reaction of 4-hydroxy-2H (or alkyl)-1,2-benzothiazine-3-carboxylic methyl ester 1,1-dioxide and 1-amino-2-thio-3-aralkyl-4-imidazolones in xylene. The compounds synthesized were screened for antiinflammatory effect on carrageeenin-induced edema in rat and for analgesic effect on acetic acid-induced Writhing syndrome in mice. Most compounds were inhibitors of carrageenin-induced rat foot edema and some showed significant antiinflammatory activity comparable to that of indomethacin and significant analgesic activity comparable to that of indomethacin and aspirin.     

Synthesis and biological evaluation of 1-(1,2-benzisothiazol-3-yl)- and (1,2-benzisoxazol-3-yl)piperazine derivatives as potential antipsychotic agents

Members of the series of title compounds were tested for potential antipsychotic activity in relevant receptor binding assays and behavioral screens. Structure-activity relationships within the series are discussed. Compound 24 (BMY 13859-1), a (1,2-benzisothiazol-3-yl)piperazine derivative, was selected for further study because of its potent and selective profile in primary CNS tests. It was active in the Sidman avoidance paradigm and blocked amphetamine-induced stereotyped behavior in dogs for up to 7 h. The compound's lack of typical neuroleptic-like effects in the rat catalepsy test and its failure to produce dopamine receptor supersensitivity following chronic administration indicate that it should not cause the movement disorders commonly associated with antipsychotic therapy. Although 24 has potent affinity for dopaminergic binding sites, its even greater affinity for serotonin receptors suggests that a serotonergic component may be relevant to its atypical profile. Compound 24 is currently undergoing clinical evaluation in schizophrenic patients.     

Design, synthesis, and anti-allergic activities of novel (R)(-)-1-[(4-chlorophenyl)phenyl methyl]piperazine derivatives

A series of novel (R)(-)-1-[(4-chlorophenyl)phenylmethyl]piperazine derivatives were designed, synthesized, and tested for in vivo anti-allergic activities. Most of these derivatives exhibited significant effects on both allergic asthma and allergic itching. Three of the 19 piperazine derivatives (namely, 3d, 3i, and 3r) have stronger potency against allergic asthma than levocetirizine, the positive control drug. Meanwhile, in the test of allergic itching, five of the 19 compounds (namely, 3b, 3g, 3k, 3o, and 3s) have more potent activities than levocetirizine.