Synthesis and in-vitro antifungal activity of 6-substituted-phenyl-2- {[(4'-substituted phenyl-5'-thioxo)-1,2,4-triazol-3-yl]-methyl}-2,3,4,5-tetrahydropyridazin-3-one derivatives

The synthetic pathway for 6-substituted phenyl-2-[{(4'-substituted phenyl-5'-thioxo)-1,2,4-triazol-3-yl}-methyl]-2,3,4,5-tetrahydropyridazin-3-one compounds was achieved by a sequence of reactions starting from respective aryl hydrocarbons and is illustrated in Scheme 1. All the compounds were tested for their in vitro antifungal activity on five fungal species, namely Candida albicans, Trichophyton rubrum, Aspergillus flavus, Aspergillus niger and Penicillium citrinium. The chloro substituent derivative (compound 5g) showed the highest activity against all the fungal species. The MIC of the standard drug voriconazole was between 0.10 - 0.40 microg/mL against all the fungal species except A. fumigatus. The two electronegative groups of Cl were increasing the activity of 1,2,4-triazole. As we increased the bulky group or aromatic group on benzene ring, there was a decrease of activity as in case of compound 1.     

Synthesis, antiviral, antituberculostic and antibacterial activities of some novel, 4-(4'-substituted phenyl)-6-(4"-hydroxyphenyl)-2-(substituted imino) pyrimidines

A variety of novel 4-[(4'-substituted phenyl)-6-(4"-hydroxyphenyl)-2-substituted imino] pyrimidines were synthesized by reacting 4-(4'-substituted phenyl)-6-(4"-hydroxyphenyl)-2-aminopyrimidines with different substituted aromatic aldehydes, with coumarin and with chloroisatin. The 4-(4'-chlorophenyl)-6-(4"-hydroxyphenyl)-2-aminopyrimidines were synthesized by reacting 3-(4'-substituted phenyl)-1-(4"-hydroxyphenyl)-2-propen-1-ones with guanine hydrochloride. The 3-(4'-substituted phenyl)-1-(4"-hydroxyphenyl)-2-propen-1-ones were synthesized by reacting 4-hydroxyacetophenone with different para substituted aromatic aldehydes. Spectral data (IR, NMR, and mass spectra) confirmed the structures of the synthesized compounds. The synthesized compounds were investigated for their antiviral, antituberculostic and antibacterial activities. The results indicated that the synthesized compounds have mild to potent activities with reference to their appropriate reference standards. However, mechanism related studies could be carried out to predict the structure activity relationship for all the compounds.     

Synthesis, antiviral, antituberculostic, and antibacterial activities of some novel, 4-(4-substituted phenyl)-6-(4-nitrophenyl)-2-(substituted imino)pyrimidines

A variety of novel 4-(4-substituted phenyl)-6-(4-nitrophenyl)-2-substituted imino) pyrimidines were synthesized by reacting 4-(4-substituted phenyl)-6-(4-nitrophenyl)-2-amino pyrimidines with different substituted aromatic aldehydes, coumarin chloroisatin. The 4-(4-substituted phenyl)-6-(4-nitrophenyl)-2-amino pyrimidines were synthesized by reacting 3-(4'-substituted phenyl)-1-(4-nitrophenyl)-2-propen-1-ones with guanine hydrochloride. 3-(4-Substituted phenyl)-1-(4-nitrophenyl)-2-propen-1-ones were synthesized by reacting 4-nitroacetophenone with different para-substituted aromatic aldehydes. Spectral data (IR, NMR, and mass spectra) confirmed the structures of the synthesized compounds. The synthesized compounds were investigated for their antiviral, antituberculostic, and antibacterial activities. The results of antiviral, antituberculostic, and antibacterial activities indicated that the synthesized compounds exhibited mild to potent activities compared to the respective reference standards.     

Synthesis of 4-amino-6-(hetaryl)pyridazin-3-ones as analogs of pyridazine-based cardiotonic agents

A series of 4-amino-6-(hetaryl)pyridazin-3-ones were synthesized for screening purposes. The target compounds were obtained on heating hydrazine hydrate with 6-(hetaryl)pyridazin-3-ones, which had been prepared via the reaction of o-diaminohetaryls with 3-pyridazine-6-carboxylic acid. Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 43, No. 2, pp. 18–19, February, 2009.     

Synthesis and antimicrobial study of fluoroquinolone-based 4-thiazolidinones

The title compounds 2-substituted phenyl-3-{1-cyclopropyl-6-fluoro-7-[4-(4-methoxyphenylpiperazin-1-yl]-4-oxo-1,4-dihydroquinoline} carboxamido-1,3-thiazolidin-4-ones 6a–j have been synthesized from lead molecule 7-chloro-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid 1; this reacted with thionyl chloride to give acid chloride 2 and with hydrazine hydrate to afford hydrazide 3. The hydrazide 3 on condensation with substituted aromatic aldehydes a–j gave Schiff base; these on reaction with N-(4-methoxyphenyl) piperazine and thioglycolic acid furnished title compounds 6a–j. All of the synthesized compounds have been established by elemental analysis. IR and NMR spectral data and have been screened for antifungal and antibacterial activities.     

1,4-bis(3-oxo-2,3-dihydropyridazin-6-yl)benzene analogues: potent phosphodiesterase inhibitors and inodilators

1,4-Bis(3-oxo-2,3-dihydropyridazin-6-yl)benzene and a series of related bis(azinone) compounds were synthesized. These novel compounds were evaluated for inhibition of the low Km, cAMP-selective, cGMP-inhibited phosphodiesterase (PDE III) derived from cat heart and hemodynamic activity in the ganglion- and beta-blocked anesthetized cat. The most potent PDE III inhibitor of the series was 6-[4-(5-methyl-3-oxo-2,3,4,5-tetrahydropyridazin-6-yl)-phenyl]p yridazin- 3(2H)-one (IC50 = 0.07 microM), which also retained the greatest inotrope and vasodilator (inodilator) potency (ED50 for first derivative of left ventricular pressure (dLVP/dt(max)) = 0.02 mumol/kg, ED15 for 15% fall in perfusion pressure = 0.01 mumol/kg). The structure-activity relationships observed within the bis(azinone) series were consistent with those reported for formally analogous 6-(4-substituted-phenyl)pyridazin-3(2H)-one-based PDE III-inhibiting inodilators with less-extended phenyl substituents (see e.g. Sircar et al. J. Med. Chem. 1987, 30, 1955, Moos et al. J. Med. Chem. 1987, 30, 1963). PDE III inhibitory potency is associated with overall planar topology of the phenylpyridazinone moiety and the presence of two critically separated electronegative centers. A methyl group at the 5-position of a dihydropyridazinone ring leads to enhanced potency. However, the generally higher levels of PDE III inhibitory potency shown by compounds in the bis(azinone) series relative to earlier 6-(4-substituted-phenyl)pyridazin-3(2H)-one derivatives appears to derive from a closer to optimal separation of two interacting points in the inhibitor molecule achieved through the more extended bis(azinone) structure. Correlation between the pharmacological and PDE III inhibitory activities of compounds in the bis(azinone) series provides additional evidence for PDE III being an important mediator of inodilator action.     

Synthesis and biological studies of triazolo-/thiadiazolo-benzoxazines

Diethyl bromomalonate (2) with an equimolar amount of 2-aminophenol (1) in the presence of sodium fluoride undergoes a cyclization reaction to form 2H,4H-2-ethoxycarbonyl-3,4-dihydro-3-oxo-1,4-benzoxazine (3). Furthermore, compound 3 undergoes a condensation reaction with hydrazine hydrate in the presence of methanol to yield 2H,4H-2-hydrazinocarbonyl-3,4-dihydro-3-oxo-1,4-benzoxazine (4), which on further reaction with aryl isothiocyanates gave 2H,4H-2-[ (4'-substituted)-phenylthiosemicarbazino]-carbonyl-3,4-dihydro-3-oxo-1,4-benzoxazine (5). Compound 5 on treatment with NaOH, cone. H2SO4 and diethylmalonate (6). afforded 2H,4H-2-[2'H-3'-thioxo-4'-substituted phenyl-1',2',4'-triazole-5-yl]- 3,4-dihydro-3-oxo-1,4benzoxazine (7). 2H,4H-2-[2'-amino-(substituted)-phenyl-1,3',4'-thiadiazol-5-yl]-3,4-dihydro-3-oxo-1,4-benzoxazine (8) and 2H,4H-2-[5'H-5'-dihydro-2'-thioxo-3'-phenyl-4',6'-dioxo-1,3-diazine]-aminocarbonyl-3,4-dihydro-3-oxo-1,4-benzoxazine (9), respectively. The synthesized compounds were investigated for their antibacterial activities against Gram positive as well as Gram negative bacteria with ampicillin trihydrate as standard drug. Structures have been elucidated on the basis of spectral and chemical analyses.     

Synthesis and activity of 6-aryl-3-(hydroxypolymethyleneamino)pyridazines in animal models of epilepsy

A series of 6-aryl-3-(hydroxypolymethyleneamino)pyridazines derivatives was synthesized and evaluated for anticonvulsant activity. The compounds were screened in mice for their ability to antagonize maximal electroshock- and bicuculline-induced seizures; neurotoxicity was evaluated in the rotorod test. The anticonvulsant activity of the most potent compounds in this series was also examined in kindled amygdaloid rats and in photoepileptic Papio papio baboons. Phenobarbital, diphenylhydantoin, carbamazepine, and sodium valproate were used as standard antiepileptic drugs. The structure-activity relationships in this series were examined by either varying the aryl ring in the 6-position of the pyridazine ring or by modifying the 3-amino side chain. Only the compounds with a phenyl ring in the 6-position of the pyridazine ring exhibited appreciable anticonvulsant activity. Furthermore, a 4-hydroxypiperidine side chain in the 3-position of the pyridazine ring appeared essential for anticonvulsant activity. Substituting the phenyl ring with a Cl in the 2-position led to a substantial increase of activity; disubstituting the phenyl ring with a Cl in the 2- and 4-positions yielded the most potent compounds in this series, some of which were as potent or more potent than phenobarbital. Two compounds, 6-(2-chlorophenyl)-3-(4-hydroxypiperidino)pyridazine (2) and 6-(2,4-dichlorophenyl)-3-(4-hydroxypiperidino)pyridazine (3), were selected for further studies. Clinical evaluation of these compounds is in progress.     

Synthesis and cardiac electrophysiological activity of 2- and 3-[(substituted phenyl)alkyl]quinuclidines. Structure-activity relationships

The syntheses and cardiac electrophysiological effects of 21 2- and 3-substituted quinuclidines and some quaternary ammonium derivatives are described. The 2-substituted quinuclidines 2-8 were prepared by alkylation of 2-methylene-3-quinuclidinone. The Wittig reaction with 3-quinuclidinone afforded the 3-substituted derivative 9, which was subsequently converted to 10 and 11. The electrophysiological profiles of the compounds were determined in canine cardiac Purkinje fibers and ventricular muscle strips. The 3-[(substituted phenyl)alkyl]quinuclidines selectively increased action potential duration (Vaughan Williams class III activity). In the 2-substituted series some of the compounds both increased action potential duration and decreased conduction velocity (class I activity). For some of the 2-substituted quinuclidines, appropriate substitution of the phenyl ring was shown to be a requirement for significant class III electrophysiological activity. Selected compounds were efficacious in a programmed electrical stimulation model in the anesthetized dog.     

Synthesis of some new 2-(6-methoxy-2-naphthyl)- 5-aryl-1,3,4-oxadiazoles as possible non-steroidal anti-inflammatory and analgesic agents

The synthesis of some new 2-(6-methoxy-2-naphthyl)-5-aryl-1,3,4-oxadiazoles (4a-k) has been described. Ethyl-6-methoxy-2-naphthoate (1) yielded on treatment with hydrazine hydrate to 6-methoxy-2-naphthoic acid hydrazide (2). Compound 2 reacted with substituted aromatic carboxylic acids (3a-k) in phosphorus oxychloride yielded 2-(6-methoxy-2-naphthyl)-5-aryl-1,3,4-oxadiazoles (4a-k). Newly synthesized compounds were characterized by IR, (1)H-NMR and mass spectral data. All the compounds were screened for their anti-inflammatory and analgesic activity. Compound 4j exhibited promising anti-inflammatory and analgesic activities.     

Potential antiinflammatory compounds. 2. Acidic antiinflammatory 1,2-benzisoxazoles

A number of 1,2-benzisoxazoles, substituted in the 3 position with 4-substituted phenyl groups and in the 5--7 positions with acetic and propionic acid residues, have been synthesized and tested in the rat carrageenan foot edema assay. Activity has been found in the 6- and 7-substituted acids.     

Synthesis and docking studies of N-(5-(alkylthio)-1,3,4-oxadiazol-2-yl)methyl)benzamide analogues as potential alkaline phosphatase inhibitors

A series of N-(5-(alkylthio)-1,3,4-oxadiazol-2-yl)methyl)benzamides 6a–i were synthesized as alkaline phosphatase inhibitors. The intermediate 5-substituted 1,3,4-oxadiazole-2-thione 4 was synthesized starting with hippuric acid. Hippuric acid in the first step was converted into corresponding methyl ester 2 which upon reaction with hydrazine hydrate furnished the formation of hydrazide 3 . The hippuric acid hydrazide was then cyclized into 5-substituted 1,3,4-oxadiazole-2-thione 4 . The intermediate 4 was then reacted with alkyl or aryl halides 5a–5i to afford the title compounds N-(5-(methylthio)-1,3,4-oxadiazol-2-yl)methyl)benzamides 6a–i . The bioassay results showed that compounds 6a–i exhibited good to excellent alkaline phosphatase inhibitory activity. The most potent activity was exhibited by the compound 6i having IC₅₀ value 0.420 μM, whereas IC₅₀ value of standard (KH₂PO₄) was 2.80 μM. Molecular docking studies was performed against alkaline phosphatase enzyme (PDBID 1EW2) to check binding affinity of the synthesized compounds 6a–i against target protein. The docking results showed that three compounds 6c , 6e , and 6i have maximum binding interactions with binding energy values of −8 kcal/mol. The compound 6i displayed the interactions of oxadiazole ring nitrogen with amino acid His265 having a binding distance 2.13 Ǻ. It was concluded from our results that synthesized compounds, especially compound 6i may serve as lead structure to design more potent inhibitors of human alkaline phosphatase.     

5-取代苯基,1-氢及1-正丙基吡唑烷酮-3化合物抗惊作用QASR的研究

研究了5-取代苯基吡唑烷酮-3衍生物中苯基取代基的变化对抗惊活性的影响。按照Topliss改进法设计并合成了。1-氢及1-正丙基取代的化合物各六个,找到了活性较强的化合物,为5-(对氟苯基)-1-丙基吡唑烷酮-3,其ED₅₀为14.7mg/kg。经QSAR研究,发现疏水参数∑π对活性影响较大,苯上取代基的立体参数B₄和电性参数Ⅰ×10²可以改进相关系数r。方程说明5-位苯上引入体积小的吸电子基团可使抗惊活性提高。     

2-甲基-5-取代苯氧基伯氨喹的合成及其抗疟活性

为寻找高效低毒的间日疟根治药,合成了7个2-甲基-5-取代苯氧基伯氨喹Ⅱ_1～7,以与强效的4-甲基取代类似物比较,探索构效关系。初步生物评价结果表明,化合物Ⅱ_1～7对鼠疟Plasmodium berghei的抑制性治疗作用及对鼠疟P.yoelii的病因性预防作用均明显弱于其4-甲基对应物,略低于伯氨喹。     

Synthesis and anti-inflammatory activity of some heterocyclic derivatives of phenothiazine

Some new 10-{[5'-amino-(1"-ace tyl-5"-substituted aryl-2"-pyrazolin-3"-yl)-1',3',4'-thiadiazol-2'-yl] methyl}-phenothiazines (11-16) and 10-{[5'-amino-(1"-acetyl-5"-substituted aryl-2"-pyrazolin-3"-yl)-1',3',4'-oxadiazol-2'-yl]methyl}phenothiazines (26-31) have been synthesized from 10-{[5'-substituted benzylideneacetylamino-(1',3',4'-thiadiazol-2'-yl)]methyl}phenothiazines (5-10) and 10-{[5'-substituted benzylideneacetylamino-(1',3',4'-oxadiazol-2'-yl)]methyl}phenothiazines (20-25), respectively. All these compounds of the present series have been screened in vivo for their anti-inflammatory and acute toxicity. Compounds 16 and 31 were found to be potent members of the present series, which showed 46.2% and 48.0% anti-inflammatory activity, respectively, at a dose of 50 mg/kg p.o., while standard drug, phenylbutazone, exhibited 44.52% anti-inflammatory activity at same dose. However, 10-{[5'-amino-(1"-acetyl-5"-(o-methoxyphenyl)-2"-pyrazolin-3"-yl)-1',3',4'-oxadiazol-2'-yl]methyl}phenothiazine (31) was found to be most active and less ulcerogenic compound of this series. The structure of these compounds have been elucidated by IR, 1H NMR, mass spectroscopy and elemental analysis.     

Synthesis and hypolipidemic activity of novel 2-(4-(2-amino-6-(4-substituted phenyl) pyrimidin-4-yl)-2-substituted phenoxy) acetic acid derivatives

A novel series of 2-(4-(2-amino-6-(4-substituted phenyl) pyrimidin-4-yl)-2-substituted phenoxy) acetic acid derivatives were efficiently synthesized. The synthesized compounds were evaluated for their in vivo hypolipidemic activity, using high-fat-diet-induced hyperlipidemia in rats. Some of these compounds showed significant antihyperlipidemic activity.     

6-取代苯基哒嗪的3位γ-氨基丁酸衍生物的合成及抗惊活性

GABA的合成类似物是开发新型抗惊剂和抗癫痫药物的新领域。由芳香醛与吗啉、氰化钾反应形成的α-芳基-α-(4-吗啉)乙腈,可对α,β-不饱和腈或酯进行1,4-加成,生成1,4-酮酸型化合物。此物与肼缩合,再经芳构化即得6-芳基-3(2H)哒嗪酮。后者再经氯化后。与GABA缩合,制备3-(N-GABA)-6-芳基哒嗪类及其分子内脱水产物3-(N-丁内酰胺)-6-芳基哒嗪类化合物。本文应用此法合成了17个上述苯代哒嗪的GABA衍生物,并初步测验了它们的抗惊(MES)活性。活性最强的是3-(N-GABA)-6-(2′,4′-二氯苯基)哒嗪(ED₅₀=21.05mg/kg)。     

Synthesis and antimicrobial activity of some new 3–[5-(4-substituted) phenyl-1,3,4-oxadiazole-2yl]-2- styrylquinazoline-4(3H)-ones

Several 3-[5-(4-substituted)phenyl-1,3,4-oxadiazole-2-yl]-2-styryl quinazoline-4(3H)-one were synthesized and screened for antibacterial activity against Staphylococcus aureus , Bacillus subtilis, Pseudomonas aeruginosa, and Escherichia coli and antifungal activity against Aspergillus niger and Fusariumoxysporum by the serial dilution technique. Compounds were prepared by reacting corresponding 2-methtyl quinazolinone and 4-subustituted benzaldehydes in glacial acetic acid. Physicochemical and spectral data were consistent with newly synthesized compounds. The prepared compounds were compared with previously synthesized 2-methyl-3-[5-(4-substituted)phenyl-1,3,4-oxadiazole-2-yl]-quinazoline-4(3H)-ones for antimicrobial activity. The present study revealed that styryl moiety at the second position of 4(3H) quinazolinone marginally increased the biological activity and exhibited better antibacterial than antifungal activities.     

疟原虫组织期裂殖体杀灭剂的研究:2-取代苄氧基(或甲氧基)-5-取代苯氧基-伯氨喹类似物的合成

本文报道了间日疟根治药伯氮喹2位引入取代苄氧基或甲氧基,5位引入取代苯氧基的类似物的合成。其中以化合物39及45对疟原虫组织期裂殖体的作用最强,约氏疟原虫子孢子感染的小鼠喂服100mg/kg单剂,分别有80%及90%的受试小鼠未查见原虫血症。化合物45降至20mg/kg单剂时,80%的受试小鼠也未出现原虫;对小鼠的急性毒性低于伯氨喹。     

Synthesis,pharmacological and biological screening of some novel pyrimidine derivatives

In the present study a new series of 4-substituted phenyl-6-(pyridin-2-yl)pyrimidin-2-ol (1–9) and 4-substituted phenyl-6-(pyridin-2-yl)pyrimidin-2-thiol (10–18) have been synthesized by cyclizing 3-substituted phenyl-1-(pyridin-2-yl)prop-2-en-1-one with urea/thiourea in the presence of NaOH as base (1a–18a). 3-Substituted phenyl-1-(pyridin-2-yl)prop-2-en-1-one was prepared by condensing 2-acetylpyridine with substituted benzaldehyde in the presence of 20 % NaOH as base. The structures of the newly synthesized compounds were characterized by elemental analysis, IR, ¹H NMR, ¹³C NMR, and mass spectroscopic studies. Newly synthesized compounds were screened for their anti-inflammatory, analgesic, cytotoxic, and antitubercular activities studies. Few of the compounds exhibited excellent anti-inflammatory activities compared to standard drug diclofenac sodium. Some compounds have shown moderate analgesic activities compared to standard drug pentazocine. Also, some compounds have exhibited moderate cytotoxic and antitubercular activities.