Stereoselective synthesis and in vitro antifungal evaluation of (E)- and (Z)-imidazolylchromanone oxime ethers

A series of (E)- and (Z)-2, 3-dihydro-3-(1H-imidazol-1-yl)-4H-1-benzopyran-4-one oxime ethers have been synthesized and tested for antifungal activity. Most compounds showed moderate to potent in vitro antifungal activity. Among the tested compounds, compound (E)-3d was the most active agent against Candida albicans and Aspergillus niger, and compounds (Z)-(3a) and (E)-3a were the most potent compounds against Microsporum gypseum. Detailed stereoselective synthesis, spectroscopic, and biological data are reported.     

Two new compounds from Senecio cannabifolius

Chemical investigation of the water extracts from the Senecio cannabifolius Less. led us to find two new compounds (1 and 2), along with 12 known compounds (3-14). The two new compounds were determined as (E, 4R)-4-hydroxy-4,5,5-trimethyl-3-(3-oxobut-1-enyl)cyclohex-2-enone (1) and (E)-4-((1S, 3R, 4R)-1-hydroxy-4,5,5-trimethyl-7-oxabicyclo[4.1.0]heptan-1-yl)but-1-en-3-o-ne (2), respectively. The structures of other compounds were elucidated by extensive analysis of spectral data and in comparison with the literature values. Compounds 1 and 2 were evaluated for inhibitory activity against lipopolysaccharide-induced NO production in RAW 264.7 macrophages, and compound 1 showed potent inhibitory activity with IC(50) value of 30.65?μM.     

Examination of newly synthesized 2-chloroethylnitrosoureas in preterminal leukemia L 5222 and in two transplanted neurogenic tumors

The chemotherapeutic activities of 11 chloroethylnitrosoureas, among them 10 newly synthesized compounds, were investigated in rat leukemia L 5222 and in two neurogenic rat tumors. 1-(4-Amino-2-methyl-5-pyrimidinyl)-methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU, compound 1) and cyclophosphamide (12) served as reference substances. The newly synthesized compounds were 1-(2-chloroethyl)-1-nitroso-3-(2-carboxyethyl)-urea (2-carboxyethyl-CNU, 2), 1-(2-chloroethyl)-1-nitroso-4-methyl-4-formyl-semicarbazide (methyl-formyl-amino-CNU, 3), 1-(2-chloroethyl)-1-nitroso-3-(methylene-2-pyridyl)-urea(methylene-2-pyridyl- CNU, 4), 1-(2-chloroethyl)-1-nitroso-3-(methylene-2-pyridyl)-urea hydrochloride (methylene-2-pyridyl-CNU . HCl, 5) 1-(2-chloroethyl)-1-nitroso-3-(methylene-4-pyridyl)-urea hydrochloride (methylene-4-pyridyl-CNU . HCl, 6), 1-(2-chloroethyl)-1-nitroso-3-(3-pyridino)-urea (pyridyl-3-CNU, 7), 1-(2-chloroethyl)-1-nitroso-3-(3-pyridyl)-urea hydrochloride (pyridyl-3-CNU . HCl, 8), 1-(2-chloroethyl)-1-nitroso-3-[4(2,6-dimethyl-morpholino)]-urea (dimethyl-morpholino-CNU, 9), 1-(2-chloroethyl)-1-nitrosocarbamoyl-morpholine (chloroethyl-nitroso-carbamoyl-morpholine, 10), 1-(2-chloroethyl)-1-nitroso-carbamoyl-2,6-dimethyl-morpholine (chloroethyl-nitroso-carbamoyl-dimethylmorpholine, 11). Against both neurogenic tumors cyclophosphamide was distinctly superior to all nitrosoureas. In leukemia L 5222 all nitrosoureas except compounds 7, 8, 11 effected cures. Remarkable differences in toxicity could be observed between the nitroso compounds investigated.     

Synthesis and antifungal activity of 1-[(2-benzyloxy)phenyl]-2-(azol-1-yl)ethanone derivatives: exploring the scaffold flexibility

Based on the N-(phenethyl)azole backbone of azole antifungals, we designed 1-[(2-benzyloxy)phenyl]-2-(azol-1-yl)ethanone derivatives 2 and 3, containing benzyloxyphenyl scaffold of croconazole. Also these compounds can be considered as flexible analogs, resulted from C2-C3 disconnection of 3'-chloro-3-imidazolylflavanone 1, recently described as antifungal agent. Thus, in this report, we describe the synthesis of 1-[(2-benzyloxy)phenyl]-2-(azol-1-yl)ethanone derivatives 2 and 3 and their biological evaluation against different pathogenic fungi. By comparing the antifungal activity profile of flexible compounds 2 and 3 with that of rigid analog 1, it can be inferred that lower susceptibilities (higher minimum inhibitory concentrations) were observed with flexible compounds. However, among the synthesized compounds, 1-[2-(2,4-dichlorobenzyloxy)phenyl]-2-(1H-imidazol-1-yl)ethanone hydrochloride (2g) showed comparable or more potent antifungal activity in comparison with fluconazole as a standard drug.     

A facile synthesis and anticancer activity evaluation of spiro[thiazolidinone-isatin] conjugates

The synthesis and evaluation of the anticancer activity of 3'-aryl-5'-arylidene-spiro[3H-indole-3,2'-thiazolidine]-2,4'(1H)-diones and spiro[3H-indole-3,2'-thi-azolidine]-2,4'(1H)-dione-3'-alkanoic acid esters were described. The structure of the compounds was determined by (1)H and (13)C NMR and their in vitro anticancer activity was tested in the National Cancer Institute. Among the tested compounds, (5'Z)-5'-(benzylidene)-3'-(4-chlorophenyl)spiro[3H-indole-3,2'-thia-zolidine]-2,4'(1H)-dione (IIa) and (5'Z)-3'-(4-chlorophenyl)-5'-[4-(1-methylethyl)-benzylidene]spiro[3H-indole-3,2'-thiazolidine]-2,4'(1H)-dione (IIb) were superior to other related compounds.     

3-取代三唑醇类化合物的合成及抗真菌活性

目的设计合成1-(1H-1,2,4-三唑-1-基)-2-(2,4-二氟苯基)-3-烷氧基苯基哌嗪-2-丙醇和1-(1H-1,2,4-三唑-1-基)-2-(2,4-二氟苯基)-3-取代硫醚-2-丙醇化合物,并进行体外抗真菌活性测试.方法以间二氟苯为起始原料,经多步反应,得到中间体环氧化物甲烷磺酸盐,再与各种烷氧基苯基哌嗪和取代硫醇开环得到目标化合物,按国际标准抗真菌敏感性实验方法测定其体外抗真菌活性.结果共合成12个(其中11个为新化合物)目标化合物,经元素分析,1H-NMR和IR确证结构,其中4个化合物的抗真菌活性强于对照品氟康唑和酮康唑.结论含烷氧苯基哌嗪侧链的三唑醇类化合物具有较强的抗真菌活性.     

Synthesis of some new 1-acylthiosemicarbazides, 1,3,4-oxadiazoles, 1,3,4-thiadiazoles and 1,2,4-triazole-3-thiones and their anti-inflammatory activities.

Sixteen 1-(1-naphthyloxy)acetyl-4-substituted-3-thiosemicarbazides, 2-substituted amino-5-(1-naphthyloxy)methyl-1,3,4-oxadiazoles, 2-substitutedamino-5-(1-naphthyloxy) methyl-1,3,4-thiadiazoles and 3-(1-naphthyloxy)methyl-4-substituted-1,2,4-triazole-5-thiones were synthesized. The structures of the compounds have been elucidated by UV, IR, 1H-NMR, 13C-NMR spectra and elemental analysis. The anti-inflammatory activities of the compounds were evaluated by carregeenan induced hind paw edema and air-pouch inflammation tests in mice. In carrageenan induced hind paw edema test, compounds 1a, 1d, 3d, 4a showed equivalent or higher activity compared to naproxen and phenylbutazone. In the air-pouch inflammatory model, compounds 1a, 1b, 1d, 2c, 3c, 3d, 4a and 4d showed marked anti-inflammatory activity. The ED50 values of these compounds ranged between 24-36 mg/kg. Side effects of the compounds on gastrointestinal system and kidneys were examined and none of the compound showed significant side effects.     

Two new compounds and anti-HIV active constituents from Illicium verum

Two new compounds named illiverin A (1) and tashironin A (8) were isolated from the roots of Illicium verum, together with seven known compounds: 4-allyl-2-(3-methylbut-2-enyl)-1,6-methylenedioxybenzene-3-ol (2), illicinole (3), 3-hydroxy-4,5-methylenedioxyallyl-benzene (4), (-)-illicinone-A (5), 4-allyl-4-(3-methylbut-2-enyl)-1,2-methylenedioxycyclohexa-2,6-dien-5-one (6), 3,4-seco-(24 Z)- cycloart-4(28),24-diene-3,26-dioic acid, 26-methyl ester (7) and tashironin (9). Based on 1D- and 2D-NMR data (COSY, HMQC, HMBC), the structures of the new compounds were deduced to be (E)-1-[(3-methylbut-2-enyl)oxy]-2-methoxy-4-(prop-1-enyl)benzene (1) and 11-O-debenzoyl-11alpha-O-2-methylcyclopent-1-enecarboxyltashironin (8). Compounds 1-9 were screened for anti-HIV activity in vitro whereby compounds 5 and 7 possessed moderate anti-HIV activity with EC50 values of 16.0 and 5.1 microM with SI values of 18.2 and 15.6, respectively.     

Structure-affinity relationship study on N-[4-(4-arylpiperazin-1-yl)butyl]arylcarboxamides as potent and selective dopamine D(3) receptor ligands

The benzamide PB12 (N-[2-[4-(4-chlorophenyl)piperazin-1-yl]ethyl]-3-methoxybenzamide) (1), already reported as potent and selective dopamine D(4) receptor ligand, has been modified searching for structural features that could lead to D(3) receptor affinity. Changes in the aromatic ring linked to N-1 piperazine ring led to the identification of 2-methoxyphenyl and 2,3-dichlorophenyl derivatives (compounds 6 and 13) displaying moderate D(3) affinity (K(i) = 145 and 31 nM, respectively). Intermediate alkyl chain elongation in compounds 1, 6, and 13 improved binding affinity for the D(3) receptor and decreased the D(4) affinity (compounds 18-26). Among these latter compounds, the N-[4-[4-(2,3-dichlorophenyl)piperazin-1-yl]butyl]-3-methoxybenzamide (19) was further modified with the replacement or of the 2,3-dichlorophenyl moiety (compounds 27-30) or of the 3-methoxyphenyl ring (compounds 31-41). In this way, we identified several high-affinity D(3) ligands (0.13 nM < K(i)'s < 4.97 nM) endowed with high selectivity over D(2), D(4), 5-HT(1A), and alpha(1) receptors. In addition, N-[4-[4-(2,3-dimethylphenyl)piperazin-1-yl]butyl]-3-methoxybenzamide (27) and N-[4-[4-(2,3-dichlorophenyl)piperazin-1-yl]butyl]-7-methoxy-2-benzofurancarboxamide (41) appear to be valuable candidates for positron emission tomography (PET) because of their affinity values, lipophilicity properties, and liability of (11)C labeling in the O-methyl position.     

Synthesis and biological investigations of 5-substituted pyrimidine nucleosides coupled to a dihydropyridine/pyridinium salt redox chemical delivery system

The syntheses, antiviral activities, and partition coefficients (P) of 3'-O-(1-methyl-1,4-dihydropyridyl-3-carbonyl)-coupled nucleosides are described. These novel compounds were designed in an effort to enhance the lipophilicity, and thereby the delivery to the CNS, without compromising the anti-HSV-1 activity of the parental nucleosides. We have previously reported the synthesis of 3'-O-(1-methyl-1,4-dihydropyridyl-3- carbonyl) analogs of 5-iodo-(5), 5-vinyl-(6), and (E)-5-(2-iodovinyl)-2'-deoxyuridines (7). We now report the synthesis of 5-iodo-3'-O-(1-methyl-1,4-dihydropyridyl-3- carbonyl)-5'-O-acetyl-2'-deoxyuridine (15) and 3'-O-(1-methyl-1,4-dihydropyridyl-3-carbonyl)-2'-deoxyuridine (17). Quarternization of the 3'-O-(3-pyridylcarbonyl) compounds (10,12) using iodomethane afforded the corresponding 1-methyl pyridinium salts (13,14) which were reduced with sodium dithionite to yield the corresponding 3'-O-1-methyl-1,4-dihydropyridyl-3-carbonyl compounds (15,16). The deprotection of 3'-O-(1-methyl-1,4-dihydropyridyl- 3-carbonyl)-5'-O-t-butyldimethylsilyl-2'-deoxyuridine (16) with Bu4N+F- afforded 3'-O-(1-methyl-1,4-dihydropyridyl-3-carbonyl)-2'-deoxyuridine (17). Compounds 5-7 and 15 were evaluated for their antiviral activity in vitro against HSV-1, HSV-2, HCMV, and VZV, and were found to retain anti-HSV-1, HSV-2 and VZV activity as compared to their parental nucleosides (1-3). In addition, the cellular toxicity of 3'-O-(1-methyl-1,4-dihydropyridyl-3-carbonyl)-coupled compounds (5-7 and 15) was found to be lower than the parent nucleosides. The lipophilicity of compounds (5-7,15,17) are enhanced substantially, compared to the parent nucleosides, as indicated by an increase in corresponding P values (1-octanol-water) upon replacement of the C-3' hydroxyl by 1-methyl-1,4-dihydropyridyl-3-carbonyl moiety.     

Activity of new iminium compounds against bacteria and fungi. 28. Synthesis of 1-ethyl-, 1-n-dodecyl-2-phenyl-3-(n-alkylthiomethyl)- and 1-ethyl-, 1-n-dodecyl-2-phenyl-3-(n-alkoxymethyl)imidazolium chlorides]

The synthesis of quaternary imidazolium compounds was performed by reaction of 1-ethyl- or 1-n-dodecyl-2-phenylimidazole with chloromethyl-n-alkyl ether or chloromethyl-n-alkyl sulfid. The antibacterial properties of the compounds obtained were tested on 13 strains of bacteria and fungi. 1-Ethyl-2-phenyl-3-(n-decylthiomethyl)-, 1-ethyl-2-phenyl-3-(n-dodecylthiomethyl)imidazolium chloride and 1-n-dodecyl-2-phenyl-3-(n-butylthiomethyl)-, 1-n-dodecyl-2-phenyl-3-(n-hexylthiomethyl)imidazolium chloride indicated the best antibacterial activity.     

1-[3-(Diarylamino)propyl]piperidines and related compounds, potential antipsychotic agents with low cataleptogenic profiles

On the basis of a structural model of the postsynaptic dopaminergic antagonist pharmacophore, a series of 1-[3-(diarylamino)propyl]piperidines and related compounds was synthesized and evaluated for potential antipsychotic activity. For a rapid measure of activity, the target compounds were initially screened in vitro for inhibition of [3H]haloperidol binding and in vivo in a test of locomotor activity. Behavioral efficacy of compounds identified from the initial screens was more accurately measured in rats by using a suppression of high base-line medial forebrain bundle self-stimulation test model. The propensity of these compounds for causing extrapyramidal side effects was evaluated by using a rat catalepsy method. On the basis of these test models, we have shown that the methine carbon of the 1-(4,4-diarylbutyl)piperidines can be advantageously replaced with a nitrogen atom. The 1-[3-(diarylamino)propyl]piperidines were less cataleptic than the corresponding 1-(4,4-diarylbutyl)piperidines. The compounds with the widest separation between efficacious dose and cataleptic dose are 8-[3-[bis(4-fluorophenyl)amino]propyl]-1-phenyl-1,3,8-triazaspiro [4. 5]decan-4-one (6), 1-[1-[3-[bis(4-fluorophenyl)amino]propyl]-4-piperidinyl]-1,3-dihydro- 2H-benzimidazol-2-one (11), 1-[1-[3-[bis(4-fluorophenyl)amino]propyl]-1,2,3,6-tetrahydro-4- pyridinyl]-1,3-dihydro-2H-benzimidazol-2-one (22), and 1-[3-[bis(4-fluorophenyl)amino]propyl]-4-(2-methoxyphenyl)piperazine (26).     

Synthesis and antimicrobial activity of some 1,3,4-oxadiazole derivatives

Six new 5-(1-/2-naphthyloxymethyl)-1,3,4-oxadiazole-2(3H)-thione, 2-amino-5-(1-/2-naphthyloxymethyl)-1,3,4-oxadiazole, 5-(1-/2-naphthyloxymethyl)-1,3,4-oxadiazole-2(3H)-one derivatives have been synthesized from 1-and/or 2-naphthol. The structures of the compounds were confirmed by IR and 1H NMR spectral data and microanalysis. The antimicrobial properties of the compounds were investigated against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, Candida albicans, C. krusei and C. parapsilosis using microbroth dilution method. 2-Amino-5-(2-naphthyloxymethyl)-1,3,4-oxadiazole and 5-(2-naphthyloxymethyl)-1,3,4-oxadiazole-2(3H)-one show significantly (32 microg/ml), compounds 5-(1-/2-naphthyloxymethyl)-1,3,4-oxadiazole-2(3H)-thione, 2-amino-5-(1-naphthyloxymethyl)-1,3,4-oxadiazole and 5-(1-naphthyloxymethyl)-1,3,4-oxadiazole-2(3H)-one moderately (64 microg/ml) active against C. krusei. All the compounds were active against S. aureus, E. coli, P. aeruginosa, C. albicans, and C. parapsilosis at 64-256 microg/ml concentration.     

5-氨基-6,8-二氟-1-(5-氟-2-吡啶基)-7-(3-甲基-1-哌嗪基)-1,4-二氢-4-氧代喹啉-3-羧酸及其类似物的合成及其抗菌作用

目的设计合成1-位为5-氟-2-吡啶基的吡酮酸衍生物,并对其抗菌活性进行初步评价.方法以2,3,4,5-四氟-6-硝基苯甲酰基乙酸乙酯和2,4,5-三氟-3-甲氧基苯甲酰基乙酸乙酯为原料,经多步反应合成8个5-氨基-6,8-二氟-1-(5-氟-2-吡啶基)-7-(3-甲基-1-哌嗪基)-1,4-二氢-4-氧代喹啉-3-羧酸及其类似物.结果共合成15个新化合物,经¹HNMR和MS确证其结构,其中8个(8-15)为目标物.结论8个目标物对金黄色葡萄球菌-16、大肠埃希氏菌-26和铜绿假单孢菌-17的体外活性均低于环丙沙星.     

Synthesis, structure, and antiparasitic activity of sulfamoyl derivatives of ribavirin

The triazole nucleoside derivatives 1-(5'-O-sulfamoyl-beta-D-ribofuranosyl) [1,2,4]triazole-3-carboxamide (2), 1-(5'-O-sulfamoyl-beta-D-ribofuranosyl) [1,2,4]triazole-3-thiocarboxamide (3), and 1-(5'-O-sulfamoyl-beta-D-ribofuranosyl)-[1,2,4]triazole-3- carbonitrile (4) were synthesized. Suitably protected triazole nucleosides were converted to their corresponding 5'-sulfamoyl derivatives, which on subsequent deprotection gave the desired compounds in good yields. The structures of compounds 2-4 were confirmed by X-ray crystallographic analysis. All three compounds showed significant antiparasitic activity in vitro, while 2 showed significant activity in vivo against Leishmania donovani and Trypanosoma brucei.     

3-(4-哌嗪-1-苯基)-6-取代-s-三唑并［3,4-b］［1,3,4］噻二唑盐酸盐的合成及抗菌活性

为了研究水溶性稠杂环化合物的合成方法及抗菌活性，本研究采用3-(4-氯苯基)-6-取代-s-三唑并［3,4-b］［1,3,4］噻二唑(2a～n)在相转移催化剂TBAI作用下与哌嗪发生亲核取代，再与盐酸成盐制备了3-(4-哌嗪-1-苯基)-6-取代-s-三唑［3,4-b］［1,3,4］噻二唑盐酸盐(3a～n)。用试管二倍稀释法研究了新化合物的体外抗菌活性。结果表明，合成的28个新化合物极性碱性哌嗪基的引入可提高化合物的抗菌活性。该类稠杂环化合物的结构有待进一步优化。     

Two new aromatic compounds from the resin of Styrax tonkinensis (Pier.) Craib

Two new aromatic compounds, trans-(tetrahydro-2-(4-hydroxy-3-methoxyphenyl)-5-oxofuran-3-yl)methyl benzoate (1), 3-(4-hydroxy-3-methoxyphenyl)-2-oxopropyl benzoate (2) and one new natural product, 4-((E)-3-ethoxyprop-1-enyl)-2-methoxyphenol (3) together with five known aromatic compounds have been isolated from the resin of Styrax tonkinensis (Pier.) Craib. Their structures were determined by physical and spectroscopic methods.     

Synthesis and antihypertensive activity of 1-(2-thiazolyl)-3, 5-disubstituted -2-pyrazolines

Several substituted 3-aryl-1-(4-aryl-2-thiazolyl)-5-(3-pyridyl)-2-pyrazolines were synthesized by reacting substituted 3-aryl-5-(3-pyridyl)-1-thiocarbamoyl-2-pyrazolines with phenacyl bromide in ethanol. The structures of all compounds were confirmed by IR, (1)H-NMR, mass spectral data and elemental analyses. The antihypertensive activity of compounds was examined by the tail-cuff method and compared with clonidine. Compounds 24-28 showed significant antihypertensive activity.     

Synthesis and evaluation of N-substituted cis-N-methyl-2-(1-pyrrolidinyl)cyclohexylamines as high affinity sigma receptor ligands. Identification of a new class of highly potent and selective sigma receptor probes

Certain benzeneacetamides [(-)- and (+)-cis-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl) cyclohexyl]benzeneacetamide] were recently reported to be potent sigma receptor ligands. In order to determine whether efficacy for the sigma receptor could be improved, a series of compounds related to the benzeneacetamides, N-substituted cis-2-(1-pyrrolidinyl)-N-methylcyclohexylamines, were synthesized and their structure-activity requirements were determined. The compounds were synthesized by starting with the previously reported (+/-)-, 1S,2R-(+)-, and 1R,2S-(-)-cis-2-(1-pyrrolidinyl)-N-methylcyclohexylamines. Analysis of sigma ([3H](+)-3-PPP), kappa ([3H]bremazocine and [3H]U69,593), dopamine-d2 ([3H](-)-sulpiride), and phencyclidine (PCP) ([3H]TCP) receptor binding in guinea pig brain revealed a number of highly potent and selective sigma receptor ligands. Notably, 1S,2R-cis-(-)-N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl]-(2-naphthyl) acetamide [(-)-29] (Ki = 8.66 +/- 0.35 nM), (+/-)-cis-2-amino-4,5-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl] benzeneacetamide [(+/-)-17] (Ki = 11 +/- 3 nM), 1S,2R-(-)-cis-N-methyl-N-[2-(3,4-dichlorophenyl)ethyl]-2-(1-pyrrolidinyl ) cyclohexylamine [(-)-44] (Ki = 1.3 +/- 0.3 nM), and 1R,2S-(+)-cis-N-methyl-N-[2-(3,4-dichlorophenyl)ethyl]-2-(1-pyrrolidinyl ) cyclohexylamine. [(+)-44] (Ki = 6 +/- 3 nM) exhibited very high affinity at sigma receptors, by displacement of [3H]-(+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine [( 3H]-(+)-3-PPP). These compounds showed insignificant affinity for kappa, dopamine, or PCP receptors, making them valuable tools for the study of sigma receptors. Furthermore, these compounds also exhibited enantioselectivity ranging from 5-fold for (+)- and (-)-44 to 160-fold for (+)- and (-)-29. Several other compounds showed equivalent selectivity but displayed lower sigma receptor affinity.     

Synthesis and monoamine oxidase inhibitory activities of 1-thiocarbamoyl-3,5-diphenyl-4,5-dihydro-1H-pyrazole derivatives

Ten new 1-thiocarbamoyl-3-(phenyl and/or 4-substituted phenyl)-5-(3,4-dimethoxyphenyl and/or 2-chloro-3,4-dimethoxyphenyl)-4,5-dihydro-1H-pyrazole derivatives were synthesized by reacting 1,3-diphenylpropen-1-ones and thiosemicarbazide. The chemical structures of the compounds were verified by means of their IR, 1H-NMR, ESI-MS spectroscopic data and elementary analyses. All the compounds were investigated for their ability to selectively inhibit monoamine oxidase (MAO) by in-vitro tests. Monoamine oxidase was isolated and purified from the mitochondrial extracts of rat-liver homogenates and human platelets. Monoamine oxidase inhibitory activities of the compounds were compared with pargyline and clorgyline. Most of the compounds inhibited the total activity of rat liver homogenates. The monoamine oxidase-A inhibitory effects of 1-thiocarbamoyl-3-(4-methoxyphenyl)-5-(3,4-dimethoxyphenyl)-4,5-dihydro-1H-pyrazole and 1-thiocarbamoyl-3-(4-methoxyphenyl)-5-(2-chloro-3,4-dimethoxyphenyl)-4,5-dihydro-1H-pyrazole were detected as potent as clorgyline. Selective and irreversible inhibition of rat liver monoamine oxidase-A by synthesized compounds have promising features for designing the new selective monoamine oxidase A inhibitors as potent and reliable anti-depressants in the future.