Synthesis of 3-(α-chlorophenylhydrazono)heteroarylmethyl-2-oxo-1,2-dihydroquinoxalines with antimicrobial activity

The reactions of 3-(α-chlorophenylhydrazono)hydrazinocarbonylmethyl-2-oxo-1,2-dihydroquinoxalines 4a,c with triethyl orthoesters resulted in the intramolecular cyclization to give the 3-(α-chlorophenylhydrazono-1,3,4-oxadiazol-2-ylmethyl)-2-oxo-1,2-dihydroquinoxalines 5a-d , but not the 1,2,4,5-tetrazepinylquinoxalines 6a-d . The cyclization mode into the 1,3,4-oxadiazole ring was confirmed by the alternate syntheses of 5a,c from the reactions of the 3-(1,3,4-oxadiazol-2-ylmethylene)-2-oxo-1,2,3,4-tetrahydroquinoxalines 7a,b with o-chlorobenzenediazonium chloride. Moreover, the reactions of 3-(benzimidazol-2-ylmethylene)-2-oxo-1,2,3,4-tetrahydroquinoxaline hydrochloride 8 with o-, m- and p-chlorobenzenediazonium chlorides afforded the 3-(α-chlorophenylhydrazonobenzimidazol-2-ylmethy])-2-oxo-1,2-dihydroquinoxa]ine hydrochlorides 9a-c , respectively. Compounds 5a-d and 9a-c were found to exhibit antimicrobial activities.     

Tautomeric behavior of 3-(α-arylhydrazono)methyl-2-oxo-1,2-dihydroquinoxalines between hydrazone imine and diazenyl enamine forms

3-(α-Chlorophenylhydrazono-1,3,4-oxadiazol-2-ylmethyl)-2-oxo-1,2-dihydroquinoxalines 4a-d and 3-(α-chlorophenylhydrazono)methoxycarbonylmethyl-2-oxo-1,2-dihydroquinoxalines 5a-c have been clarified to exhibit the characteristic tautomeric equilibria between the hydrazone imine form C and the diazenyl enamine form D with a long-range prototropy by means of the pmr and ¹³C-nmr spectroscopies.     

Synthesis and conversions of 3-(4-amino-5-methyl-4H-1,2,4-triazol-3-ylmethylene)-2-oxo-1,2,3,4-tetrahydroquinoxaline

The reaction of the hydrazone 3a with hydrazine hydrate in DBU/ethanol conveniently gave 3-(4-amino-5-methyl-4H-1,2,4-triazol-3-ylmethylene)-2-oxo-1,2,3,4-tetrahydroquinoxaline 6 . The reactions of 6 with an equimolar and 2-fold molar amount of nitrous acid afforded 3-(α-hydroxyimino-4-amino-5-methyl-4H-1,2,4-triazol-3-ylmethyl)-2-oxo-1,2-dihydroquinoxaline 9 and 3-(α-hydroxyimino-5-methyl-2H-1,2,4-triazol-3-ylmethyl)-2-oxo-1,2-dihydroquinoxaline 10 , respectively, which were converted into the 3-heteroarylisoxazolo[4,5-b]quin-oxalines 13a,b and 11 , respectively. Compound 9 was also cyclized into the 8-quinoxalinyl-1,2,4-triazolo-[3,4-f][1,2,4]triazines 14a,b .     

1H-NMR study on the tautomer ratios between the hydrazone imine and diazenylenamine forms in 3-(arylhydrazono)-methyl-2-oxo-1,2-dihydroquinoxalines

The o-substituted 3-(arylhydrazono)methyl-2-oxo-1,2-dihydroquinoxalines 1a-c and 2a , c were synthesized to investigate the tautomeric behavior between the hydrazone imine A and diazenylenamine B forms in a series of mixed dimethyl sulfoxide/trifluoroacetic acid media. The chemical shifts of the hydrazone NH, N₄-H, hydrazone CH, and diazenyl CH protons for o-, m-, and p-substituted 3-(arylhydrazono)methyl-2-oxo-1,2-dihydroquinoxalines 1 and 2 synthesized so far are summarized in Tables 3 and 4, respectively, which are found to be useful for the specification of the proton signals due to the hydrazone imine form A (hydrazone NH, hydrazone CH) and diazenylenamine form B (N₄-H, diazenyl CH).     

1,3,4-噁二唑键联二芳基乙烯化合物的合成及性质

将1,3,4-噁二唑基团引入二芳基乙烯分子中, 合成了2种新的二芳基乙烯类光致变色化合物1-氰基-2-(2H-5-苯基-1,3,4-噁二唑)-1,2-二(2,4,5-三甲基-3-噻吩)乙烯(3)和1,4-二{[1-氰基-2-(2H-5-苯基-1,3,4-噁二唑)-1,2-二(2,4,5-三甲基-3-噻吩)乙烯]-1,3,4-噁二唑}苯(4). 通过IR, NMR, MS和元素分析对化合物进行了结构表征, 并研究了其UV-Vis吸收、荧光发射、动力学特性和抗疲劳性质. 实验结果表明, 化合物[STHZ]3[STBZ]和[STHZ]4[STBZ]具有良好的光致变色性质, 光致变色闭环反应为零级反应, 开环反应为一级反应.     

Synthesis of 4H-1,3,4-oxadiazino[5,6-b]quinoxalines from 2-substituted quinoxaline 4-oxides

The reaction of 6-chloro-2-(1-methylhydrazino)quinoxaline 4-oxide 8 with acetic anhydride resulted in the intramolecular cyclization to give 8-chloro-2,4-dimethyl-4H-1,3,4-oxadiazino[5,6-b]quinoxaline 7a , while the reaction of compound 8 with acetic anhydride/pyridine or acetic anhydride/acetic acid afforded 3-(2,2-diacetyl-1-memymydrazmo)-7-chloro-2-oxo-1,2-dihydroquinoxaline 9 , effecting no intramolecular cyclization. The reaction of 2-(2-acetyl-1-methylhydrazino)-6-chloroquinoxaline 4-oxide 10a or 6-chloro-2-(1-methyl-2-trifluoroacetylhydrazino)quinoxaline 4-oxide 10b with phosphoryl chloride provided compound 7a or 8-chloro-4-memyl-2-trifluoromethyl-4H-1,3,4-oxadiazino[5,6-b]quinoxaline 7b , respectively. The reaction of compound 7b with phosphorus pentasulfide gave 7-chloro-3-(1-methyl-2-trifluoroacetylhydrazino)-2-thioxo-1,2-dihydroquinoxaline 11 , whose dehydration with sulfuric acid in acetic acid afforded 8-chloro-4-methyl-2-trifluoromemyl-4H-1,3,4-thiadiazino[5,6-b]quinoxaline 12 .     

Synthesis of 3-acylamino-2-oxazolidinone derivatives through cyclic transformations of 5-aryl (or benzyl)-1,3,4-oxadiazol-2(3H)-one derivatives

New 3-acylamino-2-oxazolidinone derivatives 3 were obtained in good yields by reaction of 5-aryl (or benzyl)3-(2-hydroxyethyl)1,3,4-oxadiazol-2(3H)ones 1 with sodium ethylate. Treatment of ethyl 5-aryl-2-oxo-1,3,4-oxadiazole-3(2H)-acetates 7 with aromatic aldehydes in the presence of sodium ethylate or sodium hydride afforded 3-acylamino-5-aryl-4-ethoxycarbonyl-2-oxazolidinone derivatives as two trans- 5 and cis- 6 racemics. Only RS,SR-racemates were obtained with acetophenone under the same conditions.     

3-(α-azidoalkyl)quinoxalin-2(1H)-ones and related alkylquinoxalinyl ketones

A convenient method has been developed for the synthesis of 3-alkanoyl-and 3-benzoyl-2-oxo-1,2-dihydroquinoxalines from the corresponding 3-(α-azidoalkyl)quinoxalines using acetic acid. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 574–577, 2007.     

Reaction of 3-phenyl-3-chloro-2-oxopropionic acid derivatives with ortho-phenylenediamine

Conclusions The reaction of dialkylamides of 3-phenyl-3-chloro-2-oxopropionic acid with orthophenylenediamine gave 2-(N,N-dialkylcarbamoyl)-1,4-dihydroquinoxalines, while esters of this acid react with ortho-phenylenediamine to give 3-(-chlorobenzyl)-2-oxo-1,2-dihydro-quinoxalines, which react with phosphites to yield the corresponding 3-(O,O-dialkylphos-phonobenzyl)-2-oxo-1,2-dihydroquinoxalines.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1412–1414, June, 1989.     

Chemistry of iminofurans: V. Synthesis,structure, and cyclization of 4-R-4-oxo-2-[2-(2-oxo-1,2-diphenylethylidene)hydrazino]but-2-enoic acids

Reactions of 1,2-diphenylethane-1,2-dione hydrazone with 4-aryl-2-hydroxy-4-oxobut-2-enoic and 2-hydroxy-5,5-dimethyl-4-oxohex-2-enoic acids provided 4-aryl-4-oxo-2-[2-(2-oxo-1,2-diphenylethylidene) hydrazino]but-2-enoic and 5,5-dimethyl-4-oxo-2-[2-(2-oxo-1,2-diphenylethylidene)hydrazino]hex-2-enoic acids. The acids derivatives can exist in solutions as Z- and β-enehydrazino-or β-ketohydrazone forms, and under the treatment with acetic anhydride they undergo cyclization into 5-aryl- and 5-tert-butyl-3-[2-(2-oxo-1,2-diphenylethylidene)hydrazono]-2,3-furandiones.     

A facile retro-ene reaction of 5-(methoxyamino)-3-aryl-1,3,4-oxadiazol-2(3H)-ones

5-(N-Methoxy-N-methyl)amino-3-aryl-1,3,4-oxadiazol-2(3H)-ones 3 undergo a heteroretro-ene reaction in refluxing methanol in which the leaving enophile is formaldehyde. The resulting 5-(methylimino)-3-aryl-1,3,4-oxadiazolidin-2-one 4 may be viewed as a kinetic product which tautomerizes to the more stable 5-(methylamino)-3-aryl-1,3,4-oxadiazol-2(3H)-one 5 as the thermodynamic product. Comparison of calculated reaction energies reveals that the presence of the heterocyclic ring facilitates the retro-ene reaction, but the expulsion of formaldehyde is predicted to be highly exothermic even in its absence.     

Studies on pyrrolidinones. Synthesis of 2-(5-oxo-2-pyrrolidinyl)-1,3,4-oxadiazoles and 2-(5-oxo-2-pyrrolidinyl)benzimidazoles

The condensation of pyroglutamic acids with 1,2-phenylenediamine leads to 2-(5-oxo-2-pyrrolidinyl)benzimidazoles and the cyclization of disilylated diacylhydrazines derived from the same acids gives 2-(5-oxo-2-pyrrolidinyl)-1,3,4-oxadiazoles. These compounds show weak antifungal activity.     

以喹啉酮为核心高选择快速检测谷胱甘肽的荧光探针

为了选择性检测小分子生物硫醇,以具有优良荧光性能的喹啉酮为荧光团,依据依布硒啉中Se—N键易与硫醇分子反应的性质,将喹啉酮组块(E)-3-(5-巯基-1,3,4-恶二唑-2-基)-N-(4-甲基-2-氧代-1,2-二氢喹啉-7-基)丙烯酰胺(MQ5)与依布硒啉2-(4-溴苯基)苯并[d][1,2]硒唑-3(2H)-酮(SQ6)对接,设计合成了一种新型荧光探针(E)-N-(4-甲基-2-氧代-1,2-二氢喹啉-7-基)-3-(5-((4-(3-氧代苯并[d][1,2]硒烯唑-2 (3H)-基)苯基)硫基)-1,3,4-噁二唑-2-基)丙烯酰胺(MNQ)。 通过傅里叶变换红外光谱(FT-IR)、核磁共振波谱仪(NMR)和高分辨质谱(HRMS)和荧光光谱等测试手段对其进行了结构表征,探究了其荧光性能。 结果表明,MNQ对谷胱甘肽(GSH)有明显的荧光猝灭,在其他氨基酸等干扰时,探针具有良好的抗干扰能力,可作为识别检测GSH的荧光猝灭型探针。 检测限为2.99×10^-8 mol/L,响应时间在35 s可完成,有望作为检测谷胱甘肽的荧光探针。     

Synthesis of 5-aryl-3-carbazoyl-1,3,4-oxadiazol-2(3H)-one. Derivatives and their ring transformation into 5-benzamido-1,2,4-triazolidine-3,5-dione derivatives

Some 5-aryl-3-carbazoyl-1,3,4-oxadiazol-2(3H)-one derivatives 6 and 9 have been synthesized in two ways. The expected thermal ring transformation into 2,5-disubstituted 1,3,4-oxadiazoles did not occur but, by acid hydrolysis of 5-aryl-3-[3-benzylidene-2-methyl(or phenyl)carbazoyl]-1,3,4-oxadiazol-2(3H)-ones 6 , a new ring transformation took place and the corresponding 4-benzamido-1-methyl(or phenyl)-1,2,4-triazolidine-3,5-dione derivatives 11 were formed. The 4-amino-1-phenyl-1,2,4-triazolidine-3,5-dione ( 19 ) has been prepared and its structure was confirmed by some reactions.     

Factors which influence the formation of oxadiazoles from anthranilhydrazides and other benzoylhydrazines

The cyclization of o-aminobenzoylhydrazine ( 1a ) and its 5-methyl derivative 1b with four equivalents and with one equivalent of triethyl orthoacetate (TEOA) was studied. 3-Amino-2-methyl-4(3H)-quinazolinone ( 2a ), 3,4-dihydro-2-methyl-5H-1,3,4-benzotriazepin-5-one ( 3a ) and an imino ether derivative of 2a , N-[2-methyl-4-oxo-3(4H)quinazolinyl]ethanimidic acid ethyl ester ( 4a ) were obtained from the reaction of 1a with four equivalents of TEOA. These results were compared with those of Merour [1] who isolated 2a and 3a using the same conditions. When 1a was treated with one equivalent of TEOA, 2a, 3a , and a new product, 2-(5-methyl-1,3,4-oxadiazol-2-yl)benzenamine ( 5a ) were produced, and 4a was not. Similar results were obtained with the reactions of 1b with TEOA. Authentic samples of oxadiazoles 5a and b were prepared by alternate routes. Novel acid-catalyzed rearrangements of benzotriazepinones 3a and b , to mixtures of aminoquinazolinones 2a and b and oxadiazoles 5a and b , respectively, were found. The different relative amounts of aminoquinazolinones 2 and oxadiazoles 5 which were produced from these rearrangements allowed us to choose between two potential mechanisms for these interesting rearrangements. Treatment of 5-nitrobenzoylhydrazine ( 37 ) with four equivalents of TEOA gave three products which were characterized, but did not lead to benzotriazepinone formation.     

N-(2-(5-(3-溴-1-(3-氯吡啶-2-基)-1H-吡唑-5-基)-1,3,4-噁二唑-2-基)-4-氯-6-甲基苯基)酰胺类新化合物的合成及生物活性

以N-吡啶基吡唑甲酸和2-氨基-3-甲基苯甲酸为起始原料,经由亲核加成、环化和酰化等多步反应合成了一系列结构新颖的N-(2-(5-(3-溴-1-(3-氯吡啶-2-基)-1H-吡唑-5-基)-1,3,4-噁二唑-2-基)-4-氯-6-甲基苯基)酰胺类化合物.测试了所合成化合物的杀虫及抑菌活性,结果表明,新化合物大多化合物在200 mg·L^-1浓度下对东方粘虫(Mythimna separataWalker)具有一定的杀虫活性,尤其是N-(2-(5-(3-溴-1-(3-氯吡啶-2-基)-1H-吡唑-5-基)-1,3,4-噁二唑-2-基)-4-氯-6-甲基苯基)乙酰胺(8a)和N-(2-(5-(3-溴-1-(3-氯吡啶-2-基)-1H-吡唑-5-基)-1,3,4-噁二唑-2-基)-4-氯-6-甲基苯基)-3-氯-2,2-二甲基丙酰胺(8e)致死率可达70%;部分化合物在50 mg·L^-1浓度下对油菜菌核病菌的抑菌活性相对较好(54.5%~63.6%),优于triadimefon和chlorantraniliprole;部分化合物如N-(2-(5-(3-溴-1-(3-氯吡啶-2-基)-1H-吡唑-5-基)-1,3,4-噁二唑-2-基)-4-氯-6-甲基苯基)-3,3-二甲基丁酰胺80和N-(2-(5-(3-溴-1-(3-氯吡啶-2-基)-1H-吡唑-5-基)-1,3,4-噁二唑-2-基)-4-氯-6-甲基苯基)-4-氟苯甲酰胺(8h)对苹果轮纹病菌具有中等抑菌活性.值得注意的是,化合物8e的杀粘虫活性和对油菜菌核病菌的抑菌活性都较为突出,可用作新农药创制研究的新型参考结构.     

A new synthesis of novel 1-aryl-3-heteroaryl-1H-pyrazolo[3,4-b]quinoxalines via a Key Intermediate

The chlorination of the α-hydrazonoester 4 with phosphoryl chloride/pyridine gave 3-[α-(o-chlorophenylhydrazono)methoxycarbonylmethyl]-2-chloroquinoxaline 5 , whose cyclization with 1,8-diazabicyclo[5,4,0]-7-undecene afforded 3-methoxycarbonyl-1-(o-chlorophenyl)-1H-pyrazolo[3,4-b]quinoxaline 6 . The reaction of 6 with hydrazine hydrate provided 3-hydrazinocarbonyl-1-(o-chlorophenyl)-1H-pyrazolo[3,4-b]quinoxaline 7 , whose reactions with methyl and allyl isothiocyanates furnished 3-(2,3-dihydro-4-methyl-3-thioxo-4H-1,2,4-triazol-5-yl)-1-(o-chlorophenyl)-1H-pyrazolo[3,4-b]quinoxaline 2 and 3-(4-allyl-2,3-dihydro-3-thioxo-4H-1,2,4-triazol-5-yl)-1-(o-chloropheny)-1H-pyrazolo[3,4-b]quinoxaline 8 , respectively. Moreover, the reactions of 7 with triethyl orthoformate and orthoacetate gave 1-(o-chlorophenyl)-3-(1,3,4-oxadiazol-5-yl)-1H-pyrazolo-[3,4-b]quinoxaline 9a and 1(o-chlorophenyl)-3-(2-methyl-1,3,4-oxadiazol-5-yl)-1H-pyrazolo[3,4-b]quinoxaline 9b , respectively.     

About the synthesis of [1,2]diazepinoindole derivatives from ethyl 2-(1-methylindole)acetate, 2-indole and 3-indoleacetohydrazones

The Vilsmeier-Haack reaction with ethyl 2-(1-methylindole)acetate and N,N-Dimethylamides/phosphorus oxychloride gave (65–85%) of ethyl 2-(3-acyl-1-methylindole)acetates 2 , which when boiled with hydrazine yielded about 90% of 4,5-dihydro-6-methyl-4-oxo-3H[1,2]diazepino[5,6-b]indoles 3. The attempted cyclization of 2-(1-methylindole)acetohydrazones 6 with acyl (acetyl and benzoyl) chlorides/triethylamine, to [1,2]diazepino[5,6-b]indole derivatives was fruitless and the bis(acyl)hydrazones 9 were obtained. Several transformations of 9 are reported. Similarly, the attempted cyclization of 3-indoleacetohydrazones 14 with acetyl chloride/triethylamine to [1,2]diazepino[4,5-b]indole derivatives was also fruitless and the bis(acyl)hydrazones 16 were again obtained.     

A convenient synthesis of (z)-3-(α-alkoxycarbonyl-α-cyanomethylene)-2-oxo-1,2,3,4-tetrahydroquinoxalines and related compounds

(Z)-3-(α-Alkoxycarbonyl-α-cyanomethylene)-2-oxo-1,2,3,4-tetrahydroquinoxalines 3 and (Z)-3-(α-alkoxycarbonyl-α-cyanomethylene)-3,4-dihydrobenzo[g]quinoxalin-2(1H)-ones 5 possessing various alkoxycarbonyl groups were prepared in good yields directly from the reaction of dialkyl (E)-2,3-dicyanobutendioates 1 with o-phenylenediamine ( 2 ) or with 2,3-diaminonaphthalene ( 4 ), respectively. Furthermore, 2,3-diaminopyridine ( 6 ) and 3,4-diaminopyridine ( 7 ) were reacted with the diethyl ester 1b to give (Z)-2-(α-cyano-α-ethoxycarbonylmethylene)-1,2-dihydro-4H-pyrido[2,3-b]pyrazin-3-one ( 8 ) and (Z)-3-(α-cyano-α-ethoxycarbonylmethylene)-3,4-dihydro-1H-pyrido[3,4-b]pyrazin-2-one ( 9 ), respectively. The structural studies of 3, 5, 8 , and 9 were carried out by nmr experiments in some details.     

Cyclic transformations of 5-aryl(or benzyl)-3-(2-bromoethyl- 1,3,4-oxadiazol-2(3H)-ones into 1-aminoimidazolidin-2-one and 5,6-dihydro-4H-1,3,4-oxadiazine derivatives

5-Aryl(or benzyl)-3-(2-bromoethyl)-1,3,4-oxadiazol-2(3H)-ones 3 have been prepared. They were reacted with secondary alkylamines without any change of the heterocycle to give amino derivatives 6 , but with primary alkylamines, cyclic transformation occurred to give 1-acylamino-3-alkylimidazolidin-2-ones 7 . In the presence of sodium alcoholate, bromo compounds 3 were transformed into 2-aryl(or benzyl)-4-alkoxycarbonyl-5,6-dihydro-4H-1,3,4-oxadiazines 9 .