Synthesis and Antioxidant Evaluation of Some New Pyridopyrazolotriazine Derivatives

Diazodization of pyrazolo[3,4‐b]pyridine 1 afforded diazonium salt 2 that coupled with active methylene compounds such as 3a , 3b , 6 , 7 , 8 , 15a , 15b , 16a , 16b , 17 , and 24 in pyridine to give aryl hydrazone derivatives 4a , 4b , 9 , 10 , 11 , 18a , 18b , 19a , 19b , 20 , and 25 , respectively. The previous synthesized compounds underwent cyclization in acetic acid to give the corresponding pyridopyrazolotriazines 5a , 5b , 12 , 13 , 14 , 21a , 21b , 22a , 22b , 22c , 23 , and 26 , respectively. The newly synthesized compounds were characterized by elemental analysis and spectral data and screened for their antioxidant activities. The results of ABTS method showed clearly that compounds 1 , 4b , 5b , 11 , 20 , 25 , and 26 displayed promising in vitro antioxidant activities. Compounds 1 and 4a exhibited high protection against DNA damage induced by the bleomycine iron complex.     

Synthesis and Antimicrobial Activity of Novel Quinoxaline Derivatives

In this study, certain 3‐substituted styrylquinoxalin‐2(1H)‐ones ( 2a‐d ) and their 2‐chloro ( 3a‐d ) and 2‐piperazinyl derivatives ( 4a‐g ) were synthesized from 3‐methylquinoxalin‐2(1H)‐one ( 1 ). In addition, a series of 1‐alkyl‐3‐substituted styrylquinoxalin‐2(1H)‐ones ( 5a‐d ) was also prepared. Moreover, 3‐(N²‐arylidenehydrazinocarbonyl)quinoxalin‐2(1H)‐ones ( 8a‐c ) as well as their cyclized oxadiazolinyl derivatives ( 9a‐c ) were prepared from 3‐hydrazinocarbonylquinoxalin‐2(1H)‐one ( 7 ). Furthermore, 3‐(5‐substituted thio‐1,3,4‐oxadiazol‐2‐yl)quinoxalin‐2(1H)‐ones ( 11a‐c ) and ( 12a‐c ) were obtained from the intermediate compound ( 10 ) ‐ previously obtained via cyclization of ( 7 ) with CS₂. Likewise, 3‐(5‐oxo‐4,5‐dihydro‐(1,3,4‐oxadiazol‐2‐yl)quinoxalin‐2(1H)‐one ( 13 ), 3‐[5‐(4‐nitrophenyl)‐1,3,4‐oxadiazol‐2‐yl]‐quinoxalin‐2(1H)‐one ( 14 ) and its 2‐chloro derivative ( 15 ) were prepared from 3‐hydrazinocarbonylquinoxalin‐2(1H)‐one ( 7 ). Some of these derivatives were evaluated for antimicrobial activity in vitro and some of the tested compounds showed antibacterial or antifungal activity.     

Synthesis,Reactions and Antimicrobial Activity of Some New Indolyl‐1,3,4‐Oxadiazole,Triazole and Pyrazole Derivatives

Indole‐3‐carboxylic acid hydrazide 3 was prepared and was treated with aromatic aldehydes in ethanol to give the corresponding hydrazone derivatives 4–7 in good yields. The indole carbohydrazide was incorporated into the 3‐indolyloxadiazoles 8–11 and 18 , 3‐indolyltriazoles 13–17 and 35 , 3‐indolylpyrazole derivatives 19–23 and carbamate derivatives 26–27 . Furthermore, interaction of the carboazide 24 with hydrazine hydrate in refluxing toluene afforded the corresponding semicarbazide derivative 30 . The thiadiazine derivative 34 was also prepared. Some of these compounds were screened in vitro for their antibacterial and antifungal activity.     

Synthesis of Novel Thioglycoside Derivatives Containing Quinazolinone

A series of novel thioglycoside derivatives containing 4(3H)‐quinazolinone was designed and synthesized from 2‐chloromethyl‐quinazolin‐4(3H)‐ones and 1‐thioglycose. Several 2‐chloromethyl‐quinazolin‐4(3H)‐ones were synthesized on refluxing with 2‐(chloroacetylamino)‐benzoic acid and arylamines in acetonitrile. All of the novel compounds were characterized by IR, ¹H NMR spectra and elemental analysis. The structures of compounds 7b, 8b and 8c have been determined by X‐ray diffraction analysis.     

An Efficient Synthesis of Some New Isolated and Fused Triazole Derivatives

A facile and efficient route to 5‐hydrazinyl‐3‐phenyl‐3H‐[1,2,4]triazole 2 from the reaction of triazol‐3‐one 1 and hydrazine hydrate is described. In addition, the formation of isolated and fused triazole derivatives was prepared via reaction of 2 with some selected electrophilic reagents in basic medium.     

Synthesis of Pyridazinone Derivatives

The reaction of methyl esters of 3-methyl-2-oxo- and 2-oxo-3-phenyl-3-pentenoic acids with hydrazine hydrate and phenylhydrazine was used to synthesize new pyridazinone derivatives. These products are formed through intermediate hydrazides with subsequent cyclization. 4-Hydroxy-3-oxotetrahydropyridazines are mainly formed using equimolar amounts of the starting reagents, while the corresponding hydrazones of 3,4-dioxohexahydropyridazines are formed in the case of a two-fold excess of hydrazine hydrate or phenylhydrazine. Evidence was obtained indicating the existence of a keto–enol tautomerism for 4-hydroxy-3-oxopyridazines.     

两种吩噻嗪衍生物的合成，光学性质及其电化学性质

The synthesis, luminescence and electrochemical properties of two novel phenothiazine derivatives were presented, which exhibit good one-photon fluorescence emission. The quantum yields and solvent effects of them were studied in detail. Compound 3,7-bis（2-4＇-imidazolylbenzylidenehydrazonoethyl）-（0-ethylphenothiazine） （5） was used as an effective initiator, of which two-photon fluorescence spectra were investigated under 800 nm fs laser pulse and the measured two-photon absorption cross-section was 18 × 10^-50 cm^4·s per photon. Two-photon initiated polymerization microfabrication experiments were carried out. X-ray diffraction analyses revealed that the shape of the compound 3,7-bis（2-pyrid-4＇-ylmethylidenehydrazonoethyl）-（0-ethylphenothiazine） （4） looks like a butterfly with nearly planar wings. The dihedral angle of the two benzene rings is 37.6° and there is an obvious π-π stacking interaction between the molecules in the crystal.     

Synthesis of New Bis‐imidazole Derivatives

The reaction of aldimines with α‐(hydroxyimino) ketones of type 10 (1,2‐diketone monooximes) was used to prepare 2‐unsubstituted imidazole 3‐oxides 11 bearing an alkanol chain at N(1) (Scheme 2, Table 1). These products were transformed into the corresponding 2H‐imidazol‐2‐ones 13 and 2H‐imidazole‐2‐thiones 14 by treatment with Ac₂O and 2,2,4,4‐tetramethylcyclobutane‐1,3‐dithione, respectively (Scheme 3). The three‐component reaction of 10 , formaldehyde, and an alkane‐1,ω‐diamine 15 gave the bis[1H‐imidazole 3‐oxides] 16 (Scheme 4, Table 2). With Ac₂O, 2,2,4,4‐tetramethylcyclobutane‐1,3‐dithione or Raney‐Ni, the latter reacted to give the corresponding bis[2H‐imidazol‐2‐ones] 19 and 20 , bis[2H‐imidazol‐2‐thione] 21 , and bis[imidazole] 22 , respectively (Schemes 5 and 6). The structures of 11a and 16b were established by X‐ray crystallography.     

两个新颖的联环十二烷衍生物的合成及结构表征

2-（2＇-Oxo-3＇-oximidocyclododecyl） cyclododecanone （1） and 2-（1＇-hydroxylcyclododecyl） cyclododecanone （2） were synthesized and characterized. The conformation analysis was carried out based on the NMR, molecular mechanics calculation and X-ray diffraction. The conformation of two cyclododecyl moieties of both 1 and 2 was found to be the [3333]-2-one or [3333] square conformation both in the crystal state and the solution. The dihedral angle between carbonyl and the oxime double bond of the ring B is 180°in the crystal of 1. The protons or hydroxyl group of carbon atoms to link the two cyclododecyl moieties of 1 and 2 constitute dihedral angles of 174°in the crystal, and 175°in the solution, and the C-C 6 bond between two cyclododecyl moieties can not freely rotate in the solid state and the solution. In addition, compound 2 was the first example of a-comer-anti-monosubstituted cyclododecanone. synthesis     

Synthesis of Some New Pyrazolopyridines,Pyrazolothienopyridines, Pyrazolopyridothienopyrimidines and Pyrazolopyridothienotriazines

Pyrazolo[3,4-b]pyridine derivative 3a was prepared and reacted with methyl iodide to give 4 or 5 depending on reaction conditions. Oxidation of 3a with iodine produced the corresponding disulphide derivative 6 , whereas oxidation with KMnO 4 gave the corresponding oxo derivative 7 . Oxidation of 4 afforded the corresponding sulphone derivative 8 , which on boiling in NaOH solution gave 7 . The reaction of compound 3a with chloroacetonitrile, ethyl chloroacetate, phenacyl bromide, and chloroacetanilide afforded 9a , b , 11 , and 12 respectively. Cyclication of the products 9a , b , 11 , and 12 yielded 10a , b , 13 , and 14 respectively. The reaction of compound 14 with ethyl orthoformate, nitrous acid, acetic anhydride, benzaldehyde, urea, CS 2 , and phenyl isothiocyanate afforded compounds 15-21 respectively.     

Synthesis and Characterization of α-Bromo Chalcone Derivatives

α-Bromo chalcones containing 2-thiene ring were prepared in good yields by the condensation of 1-(thien-3-yl)ethanone with aromatic aldehydes, followed by bromination with bromine and selective dehydrobromination with triethyl amine at room temperature.     

Synthesis of Anabaseine and Anabasine Derivatives: Structural Modifications of Possible Nicotinic Agonists

Coupling nicotinoyl chloride with 3,4‐dimetoxyphenethylamine under Bischler‐Napieralski cyclization afforded the isoquinoline (4) in good yield. This latter was used as starting material to obtain with only hydrobromic acid a product with demethylation at the position 7 (5). In addition, treatment of (4) with NaBH₄/MeOH gave 6,7‐dimetoxy‐1‐(pyridin‐3‐yl)‐1,2,3,4‐tetrahydroisoquinoline (6) and unexpectedly, under mild reduction of the pyridine moiety with H₂/PtO₂/AcOH/, gave 6,7‐dimetoxy‐1‐(piperidin‐3‐yl)‐1,2,3,4‐tetrahydroisoquinoline (7) as the title compound. The unusual chemical reactivity of 4 onto acidic conditions and catalytic hydrogenation allowed us to obtain anabaseine and anabasine derivatives under mild conditions.     

4-芳基-6-芳氧甲基吗啉-3-酮衍生物的合成及其对A549肺癌细胞生长抑止活性的评价

A series of 4-aryl-6-aryloxymethylmorpholin-3-one derivatives were synthesized very efficiently from readily available starting compounds in two steps. Ring opening reactions of epoxides with aniline compounds on alumina gave corresponding β-aminoalcohols （3）. The resulting β-aminoalcohols were reacted with 2-chloroacetyl chloride to yield the desired 4-aryl-6-aryloxymethylmorpholin-3-one derivatives （5）. All compounds 5 were assayed for inhibitory activity against A549 lung cancer cell growth, and the inhibitory effect of the novel morpholin-3-ones on cell viability was dose-dependent.     

Synthesis of Novel Spiro Pyrrolidine and Pyrrolizine Derivatives by 1,3-Dipolar Cycloaddition

The 1,3‐dipolar cycloaddition of azomethine ylides derived from isatin and amino acids viz. sarcosine and proline to 2‐arylmethylidene‐5,6‐dihydroimidazo[2,1‐b]thiazol‐3(2H)‐ones afforded novel spiro pyrrolidines and pyrrolizidines regio‐ and stereoselectively in moderate yields. The products were characterized thoroughly by IR, MS, NMR together with elementary analysis.     

Application of Heteropolyacids as Heterogeneous and Recyclable Catalysts for One-Pot Synthesis of 3-Cyanopyridine Derivatives

A simple, clean and environmentally benign route to the synthesis of 3-cyanopyridines is described via a one-pot multi-component reaction of 3,4-dimethoxyacetophenone, malonitrile or ethylcyanoacetate, aldehyde and ammonium acetate using heteropolyacids as heterogeneous and recyclable catalysts in very good yields.     

新型含噻二唑环的二茂铁衍生物的合成与电化学性质研究

Three novel thiadiazolo-ferrocence derivatives containing long chain alkyl group were synthesized and characterized. The voltammetric behaviour of these thiadaizolo-ferrocene derivatives was studied on gold electrode (diameter 1 mm) in CH2Cl2/0.2 mol/L tetra-n-butylammonium hexafluorophosphate. The influence of β-cyclodextrinon the voltammetric behaviour of the compounds was also studied.     

Activated Anilide in Heterocyclic Synthesis: Synthesis of New Dihydropyridines,Dihydropyridazines and Thiourea Derivatives

A series of new dihydropyridines, butanamide, dihydropyridazines and thiourea derivatives have been prepared through the reactions of 3‐aminopyridine ( 1 ) and N‐(pyridin‐3‐yl)‐3‐(pyridin‐3‐ylimino)butanamide 3 with some electrophilic reagents, aryl diazonium salts and isothiocyanates. Elementary analysis, MS, IR, and ¹H NMR spectra confirmed the identity of the products.     

An Efficient One‐pot Synthesis of Pyrazolone Derivatives Promoted by Acidic Ionic Liquid

A new class of pyrazolone derivatives has been isolated in good to excellent yields from the 2:1 condensation reaction between 3‐methyl‐1‐phenyl‐5‐pyrazolone and arylaldehydes in the presence of ionic liquid [HMIM]HSO₄. The compounds were characterised by their IR, NMR spectra, MS and elemental analyses. The important features of the methodology are a wide application range of substrates, higher yields and shorter reaction time.     

Synthesis and Antimicrobial Activity of Novel Iminophosphocin Derivatives

Iminophosphocins 8a – 8e and 9a – 9e were synthesized in four‐step reactions via Staudinger reaction. 3‐(Bromomethyl)‐1,2,3,4,5‐pentahydro‐3λ⁵‐naphtho[1,8‐f,g][1,5,3]diazaphosphocin‐3‐one ( 3 ) was prepared by reacting tris(bromomethyl)phosphineoxide ( 1 ) with 1,8‐diaminonaphthalene ( 2 ) in the presence of triethylamine (TEA) in dry tetrahydrofuran (THF), and treated with L‐valine methyl ester ( 4 ) and bis(2‐chloroethyl)amine ( 5 ) in the presence of TEA in dry THF to get 3‐methyl‐2‐[(3‐oxo‐1,2,3,4,5‐pentahydro‐3λ⁵‐naphtho[1,8‐f,g][1,5,3]diazaphosphocin‐3‐yl)methylamino]butanoate ( 6 ) and 3‐[di(2‐chloroethyl)aminomethyl]‐1,2,3,4,5‐pentahydro‐3λ⁵‐ naphtho[1,8‐f,g][1,5,3]diazaphosphocin‐3‐one ( 7 ). The compounds 6 and 7 were treated with trichlorosilane (SiCl₃H) in dry tetrahydrofuran (THF) to form the trivalent P(III) intermediates 8 and 9 , which were further treated with various alkyl azides in dry THF in 55–60°C to afford the title compounds 8a – 8e and 9a – 9e . Their structures were established by multi‐nuclear NMR and mass spectra. All the newly synthesized compounds were found to possess moderate anti‐microbial activity.     

四氢异喹啉衍生物的合成研究

以间甲氧基苯乙胺和氯甲酸乙酯为原料,通过亲核取代、关环、铝锂氢还原、脱甲基以及在N位上Boc保护及脱保护等9步反应得到一系列重要的1,2,3,4-四氢异喹啉及其衍生物.产物的结构经核磁共振氢谱、红外光谱及元素分析确证.与传统四氢异喹啉衍生物的合成工艺相比,该工艺反应条件温和、简便、经济、产率高且对环境友好.