Active Methylene Reagents Research Articles

Heterocyclic synthesis with 4-hydrazinopyridothienopyrimidines: Synthesis of pyridothienotriazolopyrimidines and heterocyclylpyridothienopyrimidines with biological interest

Synthesis of the new 4-hydrazinopyrido[3′,2′:4,5]thieno[3,2-d]pyrimidines 7a,b was reported. Their reactivity toward a variety of carbon electrophiles and active methylene reagents was studied to give pyridothienotraizolopyrimidines as well as other substituted phthalazinyl- and pyrazolyl-pyridothienopyrimidine derivatives. The antimicrobial activity of some newly synthesized compounds was evaluated. © 2005 Wiley Periodicals, Inc. 16:298–307, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20126

The behaviour of 4-alkoxy methylene-2-phenyl-4H-oxazol-5-one and 4-dimethyl amino methylene-2-phenyl-4H-oxazol-5-one toward nitrogen nucleophiles under microwave heating

The reactivity of 4-ethoxymethylene-2-phenyloxazol-5(4H)-one and 4-dimethylamino methylene-2-phenyloxazol-5(4H)-one toward amines and active methylene reagents under microwave heating is reported. A new 3-aroylamino-4-pyridone synthesis is described.

Synthesis of some new azole, azepine, pyridine, and pyrimidine derivatives using 6‐hydroxy‐4H‐4‐oxo[1]‐benzopyran‐3‐ carboxaldehyde as a versatile starting material

AbstractCondensation of 3‐formyl chromone 1 with hydroxylamine hydrochloride afforded the corresponding oxime 2 that was converted to nitrile 3. Refluxing of oxime 2 and/or nitrile 3 with aceturic or hippuric acid gave 16 and 17. Treatment of 1 with semicarbazide hydrochloride and thiosemicarbazide afforded the corresponding carbazones 5–6 that underwent cyclization with ethyl bromoacetate and/or chloroacetone yielding 7–8. Also 1 reacted with acyclic active methylene reagents, e.g. malononitrile, ethyl cyanoacetate, and ethyl acetoacetate to form compounds 11, 12, and 13. Reaction of 1 with bifunctional reagents, e.g. benzil, o‐phenylenediamine, o‐aminophenol, and o‐aminothiophenol yielding the corresponding imidazolyl bezopyranone and azepine derivatives 14–20. Condensation of 1 with acyclic or heterocyclic compounds containing active methylene group, e.g. hippuric acid forming the condensed products 21–27. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:20–27, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20048

Pyridazine Derivatives and Related Compounds. Part 13. Synthesis and Antimicrobial Activity of Some Pyridazino[3′,4′:3,4]pyrazolo[5,1‐c]‐1,2,4‐triazines.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Novel and Facile Synthesis of Thiophene, Thiazole, 2H‐Pyran‐2‐one Benzimidazo[1,2‐a]pyridine and Pyridine Derivatives Containing Antipyrine Moiety.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Heterocyclic Synthesis with Ethyl α‐(3‐Carbamoyl‐4,5,6,7‐tetrahydrobenzo [b]thiophen‐2‐ylhydrazono)acetates: An Expeditious Synthetic Approach to Polyfunctionally Substituted Pyran, Pyridine, and Pyridazine Derivatives.

AbstractFor Abstract see ChemInform Abstract in Full Text.

The condensation of active methylene reagents with salicylaldehyde: Novel synthesis of chromene, azaanthracene, pyrano[3,4‐c]chromene and chromeno[3,4‐c]pyridine derivatives

AbstractOn heating of the cyanoacetic acid cyclopentylidene hydrazide 1 with salicylaldehyde in the presence of bases the azaanthracene derivative 6 was formed. Also, reaction of 3 with malononitrile and ketones 10a,b afforded the pyrano[3,4‐c]chromene 9 and chromeno[3,4‐c]pyridine 11 respectively. A mechanism for these reactions is proposed.

Pyridazine derivatives and related compounds. Part 13: Synthesis and antimicrobial activity of some pyridazino[3′,4′:3,4]pyrazolo[5,1- c]-1,2,4-triazines

A general method for the preparation of substituted pyridazinopyrazolotriazines is reported. 3-Aminopyrazolo[3,4- d]pyridazine was diazotized and coupled with active methylene reagents to afford the tricyclic pyridazino[3′,4′:3,4]pyrazolo[5,1- c]-1,2,4-triazines with substituents such as methyl, phenyl, ethoxycarbonyl, acetyl or benzoyl, depending on the methylene reagent used. In addition several condensation reactions with hydrazines gave the corresponding acid hydrazide and/or hydrazones. Reactions of 3 with aromatic aldehydes afforded hydrazones. The products were screened for their antimicrobial activity against five microorganisms.

Synthesis and Antimicrobial Evaluation of Some Novel Cholestane Heterocyclic Derivatives.

AbstractFor Abstract see ChemInform Abstract in Full Text.

NOVEL AND FACILE SYNTHESIS OF THIOPHENE, THIAZOLE, 2H-PYRAN-2-ONE BENZIMIDAZO[1,2-a]PYRIDINE AND PYRIDINE DERIVATIVES CONTAINING ANTIPYRINE MOIETY

Several new thiophene, thiazole, 2H-pyran-2-one, benzimidazo[1,2-a]pyridine and pyridine derivatives were synthesised from active methylene reagents, 4-chloroacetylantipyrine and enaminones as starting materials.

Nitriles in Organic Synthesis: Synthesis of Pyrido[2,1‐b]benzothiazole Derivatives and Polyfunctionally‐Substituted Pyridines.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Heterocyclic synthesis with ethyl α‐(3‐carbamoyl‐4,5,6,7‐tetrahydrobenzo[b]thiophen‐2‐ylhydrazono)acetates: An expeditious synthetic approach to polyfunctionally substituted pyran, pyridine, and pyridazine derivatives

AbstractEthyl α‐(3‐carbamoyl‐4,5,6,7‐tetrahydrobenzo[b]thiophen‐2‐ylhydrazono)acetates 1 were prepared and established as previously described by our research group. Their reactivity toward a variety of active methylene reagents was studied to give pyran, pyridine, and pyridazine derivatives. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:300–306, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20019

2-Arylhydrazonopropanals as Building Blocks in Heterocyclic Chemistry: Microwave Assisted Condensation of 2-Arylhydrazonopropanals with Amines and Active Methylene Reagents

Utilization of 2-arylhydrazonopropanals for the synthesis of 2-arylhydrazonoimino propanones, 1,2,4-trizolo[4,3-a]pyrimidines, pyridopyridazine hydrazones, 3-oxaloalkanonitriles and 1,2,3-trizole derivatives by conventional heating and under microwave irradiation is described. Structural assignments are based on spectroscopic data and confirmed in some cases by X-ray crystallography.

Nitriles in Organic Synthesis: Synthesis of Pyrido[2,1-b]benzothiazole Derivatives and Polyfunctionally-substituted Pyridines

A variety of pyrido[2,1-b]benzothiazole derivatives could be prepared by reaction of 2-cyanomethylbenzothiazole, formaldehyde, and various active methylene reagents. Also some polyfunctionally-substituted pyridines were prepared by reaction of 2-cyanomethylbenzothiazole, formaldehyde, and an α-functionally substituted acrylonitrile.

Synthesis of Some New Spirothiopyran Derivatives from the Reaction of 4-Thiopyrylidenemalononitriles with Bidentate and Active Methylene Reagents

2,6-Diphenyl and 2-phenyl-6-p-tolyl-4-thiopyrylidenemalomonitriles have been synthesized as f , g -unsaturated nitriles from the condensation of 2,6-diphenyl and 2-phenyl-6-p-tolyl-4H-thiopyran-4-thiones with malononitrile. Treatment of 4-thiopyrylidenemalononitriles with hydrazine hydrate, hydroxylamine hydrochloride, thiourea, thiosemicarbazide, or guanidine hydrochloride afforded the corresponding spirothiopyran derivatives of pyrazole, isoxazole, 1,3-thiazine or pyrimidine, respectively, while treatment with acetylacetone gave the corresponding spirothiopyran derivatives of pyran.

Synthesis of Some New Pyridazino Cinnoline Derivatives.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of Substituted Pyrazolo[3,4‐b]Pyridines

AbstractThe synthesis of different substituted pyrazolo[3,4‐b]pyridines by the reaction of 3‐amino‐5‐chloro‐1‐phenylpyrazole‐4‐carboxaldehyde 1 as starting material with some active methylene reagents has been reported.

Conformationally Constrained 1,4‐DHPs. A Convenient Route to Bis‐1,4‐DHPs as a Novel Class of Nitrogen Compounds.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of some new pyridazino cinnoline derivatives

Abstract2,5‐Dibromo‐3,6‐(dihydrazino or diphenylhydrazino)‐1,4‐benzoquinone 1a,b reacts with active methyl‐ene reagents to give some new functionally substituted pyridazino cinnoline derivatives.

Conformationally constrained 1,4-DHPs. A convenient route to bis-1,4-DHPs as a novel class of nitrogen compounds

2-Formyl-1,4-DHP derivatives 2 undergo the tandem Knoevenagel condensation/amino-nitrile cyclisation with activated methylene reagents to afford high functionalised indolizines. However, in the absence of this tandem, the Knoevenagel condensation intermediate leads to bis-1,4-DHPs as a new class of nitrogen compounds.