Potential nootropic agents, 4-alkoxy-2-(1-piperazinyl)quinazoline derivatives

A series of 4-alkoxy-2-(1-piperazinyl)quinazoline derivatives was synthesized and evaluated for its ability to reverse a scopolamine-induced learned impairment in a one-trial passive avoidance task (antiamnestic activity). 2-(4-Allyl-1-piperazinyl)-4-pentyloxyquinazoline (4) showed more potent antiamnestic activity than such reference compounds as aniracetam, idebenone and bifemelane at a wide dose range (1-30 mg/kg]. Compound 4 also exhibited potent anticonvulsive and antihypoxic activities, and was selected as the most promising nootropic candidate agent.     

Novel 4-substituted 2-piperazinylquinazolines as potent anticonvulsive and antihypoxic agents

Several types of quinazoline derivatives were prepared and examined for anticonvulsive and antihypoxic activities. Many compounds showed potent anticonvulsive activity, and their anticonvulsive profile is similar to that of phenytoin. The analysis of quantitative structure-activity relationships indicated that the anticonvulsive activity was parabolically related to the lipophilicity of the compounds. Most of the 4-alkoxyquinazolines showed potent anticonvulsive and antihypoxic activities. It is confirmed that there is a good correlation between the potencies of these activities.     

Synthesis and biological activities of new 1,4-benzothiazine derivatives.

New 2H-1,4-benzothiazin-3(4H)-one derivatives possessing (4-phenyl-1-piperazinyl)alkyl moieties at the 2-position were synthesized and tested for calcium antagonistic and calmodulin antagonistic activities. Antihypertensive effects in spontaneously hypertensive rats were also evaluated. In general, these compounds were rather weak calcium channel blockers, although, in contrast, many of them had moderate to potent calmodulin antagonistic activity, and 2-[3-(4-(4-fluorophenyl)-1-piperazinyl]propyl]-2H-1,4-benzothiazin -3 (4H)-one derivatives 45, 74 and 75 showed potent antihypertensive effects.     

Novel 1,4-dihydropyridine calcium antagonists. II. Synthesis and antihypertensive activity of 3-[4-(substituted amino)phenylalkyl]ester derivatives

Novel 1,4-dihydropyridine derivatives bearing 3-[4-(substituted amino)phenylalkyl]ester side chains were prepared and tested for their antihypertensive activity in spontaneously hypertensive rats. Most compounds showed a more potent antihypertensive effect and a longer duration of action than nicardipine. The derivatives with a benzhydrylpiperazinyl and a benzhydrylpiperidinyl group were distinctive. 2-[4-(4-Benzhydryl-1-piperazinyl)phenyl]ethyl methyl 1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-3,5-pyridinedicarboxylate (4e), its 4-(4-cyano-2-pyridyl) analogue (4f), its 3-[4-(4-benzhydryl-1-piperazinyl)phenyl]propyl ester analogue (4h), its 2-[4-(4-benzhydryl-1-piperidinyl)phenyl]ethyl ester analogue (4j), and its 2-[4-(1-benzhydryl-4-piperidinyl)phenyl]ethyl ester analogue (4k) were selected as candidates for further pharmacological investigations.     

Studies on antibacterial agents. I. Synthesis of substituted 6,7-dihydro-1-oxo-1H,5H-benzo[i,j]quinolizine-2-carboxylic acids

A series of substituted 6,7-dihydro-1-oxo-1H,5H-benzo[i,j]quinolizine-2-carboxylic acids was synthesized and tested for antibacterial activities. Among them, 9-fluoro-6,7-dihydro-5-methyl-8-(4-methyl-1-piperazinyl)-1-oxo-1H,5H- benzo[i,j]quinolizine-2-carboxylic acid (OPC-7241) exhibited potent antibacterial activity against gram-positive and -negative bacteria, including Staphylococcus aureus and Pseudomonas aeruginosa, and 9-fluoro-6,7-dihydro-8-(4-hydroxy-1-piperidyl)-5-methyl-1-oxo-1H, 5H-benzo[i,j]quinolizine-2-carboxylic acid (OPC-7251) showed potent activity characteristically against Propionibacterium acnes.     

Synthesis and antitumor activity of novel pyrimidinyl pyrazole derivatives. III. Synthesis and antitumor activity of 3-phenylpiperazinyl-1-trans-propenes

A series of novel 3-[4-phenyl-1-piperazinyl]-1-[5-methyl-1-(2-pyrimidinyl)-4-pyrazolyl]-1-trans-propenes and related compounds were synthesized and evaluated by their cytotoxic activity against several tumor cell lines in vitro and in vivo antitumor activity against some tumor models when administered both intraperitoneally and orally. Compounds with the 3-chloropyridin-2-yl group (9g) and the 3-fluoro-5-substituted phenylpiperazinyl group (29b, c, and e) showed significantly potent cytotoxicity by in vitro testing. Among them, the 3-cyano-5-fluorophenyl derivative (29b) exhibited potent antitumor activity against several tumor cells including human carcinoma without causing undesirable effects in mice.     

Synthesis and antitumor activity of novel pyrimidinyl pyrazole derivatives. II. Optimization of the phenylpiperazine moiety of 1-[5-methyl-1-(2-pyrimidinyl)-4-pyrazolyl]-3-phenylpiperazinyl-1-trans-propenes

A series of novel 3-substituted-1-[5-methyl-1-(2-pyrimidinyl)-4-pyrazolyl]-1-trans-propenes in order to improve the in vitro and in vivo activity of our prototype 3-[4-(3-chlorophenyl)-1-piperazinyl]-1-[5-methyl-1-(2-pyrimidinyl)-4-pyrazolyl]-1-trans-propene (2) were synthesized and evaluated by assays of growth inhibition against several tumor cell lines in vitro and antitumor activity against some tumor models when dosed both intraperitoneally and orally in vivo. Compounds 7a and 7e, the 3,5-difluorophenyl and 3,5-dichlorophenyl analogues of 2, respectively, showed significantly more potent cytotoxicity than 2 in vitro and potent antitumor activities without causing decrease of body temperature related to side effects.     

A novel class of antiulcer agents. 4-Phenyl-2-(1-piperazinyl)quinolines

The synthesis of a novel class of antiulcer agents, the substituted 4-phenyl-2-(1-piperazinyl)quinolines, and their pharmacological activities (inhibitory effects on hypothermia induced by reserpine and on gastric ulcers induced by stress or ethanol) are described. These compounds can be classified into three groups (a group predominantly effective on the stress-induced ulcer, one effective on both the stress- and ethanol-induced ulcers, and one selectively effective on the ethanol-induced ulcer), with regard to antiulcer activity. The inhibitory effect on stress-induced ulcer was found to be in close relation to the antagonism of hypothermia. The structure-activity relationships in these compounds are described. Among the compounds, 2-(4-ethyl-1-piperazinyl)-4-phenylquinoline dimaleate (9, AS-2646) showed a potent inhibition of stress-induced ulcer and gastric acid secretion, possively through action on the central nervous system, and it was selected for clinical evaluation.     

Synthesis of 4H-1,4-benzothiazine 1-oxide and 1,1-dioxide. Analogs of quinolone antibacterial agents

4-Cyclopropyl-5,7-difluoro-6-(4-methyl-1-piperazinyl)-4H-1,4-benzothiazine-2-carboxylic acid 1-oxide (2c) and 4-cyclopropyl-5,7-difluoro-6-(4-methyl-1-piperazinyl)-4H-1,4-benzothiazine-2-carboxylic acid 1,1-dioxide (2d) were prepared and assayed for antibacterial activity and inhibition of DNA gyrase.     

Acrylamide derivatives as antiallergic agents. I. Synthesis and structure-activity relationships of N-[(4-substituted 1-piperazinyl)alkyl]-3-(aryl and heteroaryl)acrylamides

A new series of acrylamide derivatives (7-10) were synthesized. Antiallergic activity of these compounds was evaluated and their structure-activity relationships were examined. Compound 10d, N-[4-(4-diphenylmethyl-1-piperazinyl)butyl]-3-(3-pyridyl)acrylamid e, showed antiallergic activity equivalent or superior to that of ketotifen in the rat passive cutaneous anaphylaxis (PCA) test by oral administration. Compound 10d, unlike ketotifen, had more potent in vitro 5-lipoxygenase inhibitory activity than caffeic acid, whereas its in vitro antihistamine activity was weaker than that of ketotifen. In addition, its inhibitory activity against histamine release from rat mast cells was approximately two-thirds as potent as that of disodium cromoglycate (DSCG). Compound 10d is a promising agent for treating a variety of allergic diseases.     

Synthesis of benzimidazole derivatives as potential H1-antihistaminic agents

Several types of benzimidazole derivatives were prepared and were screened for H ₁-antihistaminic activity. Most of the compounds showed potent antihistaminic activity in vitro. Among them 2-[(1-piperazinyl)methyl]-benzimidazoles 14 and 2-[(1-homopiperazinyi)methyl]benzimidazoles 15 exhibited potent activity also in vivo.     

Studies on antibacterial agents. II. Synthesis and antibacterial activities of substituted 1,2-dihydro-6-oxo-6H-pyrrolo[3,2,1-ij]quinoline-5-carboxylic acids

A series of substituted 1,2-dihydro-6-oxo-pyrrolo[3,2,1-ij]quinoline-5-carboxylic acids for the treatment of systemic infections was synthesized via 7-bromo-3-ethylthio-4,5-difluoro-2-methylindole (3), which was prepared by Gassman's indole synthesis in excellent yield. The synthesized pyrroloquinolines were tested for their antibacterial activities. 8-Fluoro-1,2-dihydro-2-methyl-9-(4-methyl-1-piperazinyl)-6-oxo-6H- pyrrolo[3,2,1-ij]quinoline-5-carboxylic acid showed a potent antibacterial activity against gram-positive and gram-negative bacteria.     

Synthesis and anxiolytic activity of N-substituted cyclic imides (1R*,2S*,3R*,4S*)-N-[4-[4-(2-pyrimidinyl)-1-piperazinyl]butyl]-2,3- bicyclo[2.2.1]heptanedicarboximide (tandospirone) and related compounds.

A series of cyclic imides bearing a omega-(4-aryl and 4-heteroaryl-1-piperazinyl)alkyl moieties was synthesized and tested in vivo for anxiolytic activity. The in vitro binding affinities of these compounds were also examined for 5-HT1A receptor sites. Structure-activity relationships within these series are discussed. One of these compounds, (1R*,2S*,-3R*,4S*)-N-[4-[4-(2-pyrimidinyl)-1-piperazinyl]butyl]-2,3- bicyclo[2.2.1]heptanedicarboximide (1: tandospirone), was found to be equipotent with buspirone in its anxiolytic activity and more anxio-selective than buspirone and diazepam. Tandospirone (1) is currently undergoing clinical evaluation as a selective anxiolytic agent.     

A concise synthesis of a novel antiangiogenic tyrosine kinase inhibitor

An efficient synthesis of the potent KDR inhibitor 3-[5-[[4-(methylsulfonyl)-1-piperazinyl]methyl]-1H-indole-2-yl]quinolin-2(1H)-one (1) is described. The process features a noncryogenic indole boronation and a dicyclohexylamine-mediated Suzuki coupling.     

Quantitative structure-activity relationships of H1-antihistaminic benzimidazole derivatives

The quantitative structure-activity relationships (QSAR) of 2-(4-substituted-1-piperazinyl)benzimidazole derivatives for antihistaminic activity were examined. Taking into consideration the specific conformations of some derivatives, a significant correlation was obtained using Verloop's STERIMOL parameters B3 and L of the substituent at the 1-position of the benzimidazole nucleus. The results indicated that the derivatives having a substituent with a small breadth and an appropriate length at the 1-position showed potent activity. From the results, a model of the binding site is proposed. The QSAR of side effects (anticholinergic activity and central nervous system depressive effect) were also examined and the results showed that a sterically small substituent at the 1-position was required to decrease side effects.     

Stereospezifität der neuroleptischen Wirkung und Chiralität von (+)-3-{2-[4-(8-Fluor-2-methyl-10,11-dihydrodibenzo[b,f]thiepin-10-yl)-1-piperazinyl]-äthyl}-2-oxazolidinon (16). 4. Mitteilung über tricyclische Antidepressiva und Neuroleptica

Stereospecifity of the neuroleptic activity and chirality of (+)-3-{2-[4-(8-fluoro-2-methyl-10, 11-dihydrodibenzo[b,f]thiepin-10-yl)-1-piperazinyl]ethyl}-2-oxazolidinone (16). The synthesis and stereospecific neuroleptic action in animals of the (+)-enantiomer of 3-{2-[4-(8-fluoro-2-methyl-10,11-dihydrodibenzo [b,f]thiepin-10-yl)-1-piperazinyl]ethyl}-2-oxazolidinone ( 16 ) are briefly described. The (10S)-configuration of this compound was determined by X-ray diffraction.     

1-对甲苯磺酰基-2-苯氧基-3-烷基-4-苯基-1,4-二氮-2-磷酰杂环戊-5-酮的合成及除草活性

我们已报道了1-对甲苯磺酰基-2-苯氧基-3-芳基-4-苯基-1,4,2-二氮磷酰杂环戊-5-酮的合成及除草活性[1],为了进一步探讨3-位取代基的变化对这类1,4,2-二氮磷酰杂环戊-5-酮的除草活性的影响,按如下方法合成了相应的3-位烷基取代的1-对甲苯磺酰基-4-苯基-1,4-二氮-2-磷酰杂环戊-5-酮（2）,并对脂肪醛与1及亚磷酸酯的酸催化反应机理进行了初步探讨．用元素分析、NMR、MS证实了化合物2的结构．初步除草活性测定结果表明,2具有一定的除草活性;其除草活性比相应的3-位芳基取代类化合物的低[1]．R：2a,H;2b,Me;2c,Et;2d,n－Pr…     

Structure-activity relationships of new N-acylanthranilic acid derivatives as plasminogen activator inhibitor-1 inhibitors

Novel anthranilic acid derivatives having substituted N-acyl side chains were designed and synthesized for evaluation as plasminogen activator inhibitor-1 (PAI-1) inhibitors. Compounds with a 4-diphenylmethyl-1-piperazinyl moiety on the acyl side chains in general exhibited potent in vitro PAI-1 inhibitory activity and good pharmacokinetic profiles after oral administration in rats. Compound 16f (TM5275) was identified as a promising candidate for further pharmacological evaluation.     

Synthesis of an indole containing KDR kinase inhibitor by tandem Sonogashira coupling-5-endo-dig-cyclization as a key step

An efficient synthesis of the potent KDR kinase inhibitor 3-[5-[[4-(methylsulfonyl)-1-piperazinyl]methyl]-1H-indol-2-yl]quinoline-2-(1H)-one using a Sonogashira coupling-5-endo-dig-cyclization strategy is described.     

Synthesis of 1-[3-methyl-2(3H)-benzazolon-5- or 6-yl]-4-{4-[cis-2-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl-methyl)-1,3-dioxolan-4-yl]methyleneoxyphenyl}piperazines

Reactions of 3-methyl-6-[4-(4-hydroxyphenyl)-1-piperazinyl]-2(3H)-benzoxazolone, 3-methyl-6-[4-(4-hydroxy-phenyl)-1-piperazinyl]-2(3H)-benzothiazolone and 1,3-dimethyl-5-[4-(4-hydroxyphenyl)-1-piperazinyl]-2(3H)-benzimidazolone with cis-{[2-(2,4-dichlorophenyl) -2-(1H-imidazol-1-ylmethyl)]-1,3-dioxolan-4-yl}methyl meth-anesulfonate in the presence of sodium hydride furnish the title compounds.