Synthesis of 2‐phenylquinolin‐4‐amines substituted with diverse amino and aminoalkyl groups

Facile synthetic approaches to 2‐phenylquinolin‐4‐amines containing an aminoalkyl group at N⁴ of the quinolin‐4‐amine and amino or aminoalkyl groups at the phenyl moiety are presented.     

Synthesis of novel 2‐amino‐6,8‐dithioxopurine derivatives

The synthesis of novel 2‐amino‐9‐alkoxyalkylpurine derivatives with both identical and different sulfur containing substituents at positions 6 and 8 of the purine cycle has been accomplished. The thionation and alkylation of the key intermediate ‐ 2‐[2‐(acetylamino)‐6,8‐dichloro‐9H‐purin‐9‐yl]methoxyethyl acetate or its reactions with thiolates were used. The structures of compounds obtained were confirmed by spectroscopic data and X‐ray diffraction analysis.     

Furan ring opening ‐ indole ring closure: Synthesis of furo[2′,3′:3,4]‐cyclohepta[1,2‐b]indolium chlorides

A new synthetic approach to furo[2′,3′:3,4]cyclohepta[1,2‐b]indolium chlorides is elaborated starting from 2‐acetylaminoaryldifurylmethanes or 2‐aminoaryldifurylmethanes under treatment with methanolic HCl solution. The reaction proceeds in three steps: recyclization, intramolecular cyclization, and disproportionation. In this case the furan ring takes part in building up both pyrrole and seven‐membered rings. The same salts can be obtained directly from 2‐acetylaminobenzaldehydes and 2‐methylfuran under similar conditions without isolation of corresponding 2‐acetylaminoaryldifurylmethanes.     

Synthesis of some new 4‐substituted‐3, 5‐bis(2‐pyridyl)‐1h‐pyrazole

Several 4‐substituted‐3, 5‐bis(2‐pyridyl)‐1H‐pyrazoles, where the substituent is chloro, bromo, iodo, nitro, diazo, were synthesized under mild reaction conditions in high yields. The structures of the products were characterized by ¹H NMR, ¹³C NMR, ESI‐MS, IR and elemental analyses.     

Synthesis and antimicrobial activity of some new N‐(substituted phenyl)‐N′‐[2,3‐dihydro‐2‐oxido‐3‐(4′‐fluorophenyl)‐1H‐(1,3,2)benzoxazaphosphorin 2‐yl]ureas

Substituted benzoxazaphosphorin 2‐yl ureas were synthesized by reacting 2‐(4‐fluoro‐phenylamino)‐methylphenol (4) with different carbamidophosphoric acid dichlorides (3) in the presence of triethylamine in dry toluene at 45‐50 °C and characterized by spectral data. These compounds were found to possess good antimicrobial activity.     

New fragmentation of 2‐isoxazoline‐5‐carboxylic acid chlorides

A novel base promoted degradation of 3‐aryl‐2‐isoxazoline‐5‐carboxylic acid chlorides to aryl nitriles has been discovered.     

Anodic cyanation of 1‐arylpyrroles

The electrooxidation of several 1‐arylpyrroles has been carried out in methanol containing sodium cyanide at a platinum anode in a divided cell. In all instances, replacement of a heteroaromatic hydrogen by a cyano group occurred. On the basis of electroanalytical results, the anodic cyanation of the title compounds could be designed an EC process. As a result of two‐electron oxidation, the corresponding pyrrole cyanides were obtained in yields ranging from 76‐85%. The advantages of electrochemistry synthesis of pyrrole cyanides are simple reaction condition, low cost and high purity products.     

Synthesis of first representatives of 3,3′‐bi(6,8‐dialkyl‐2,4‐dioxa‐6,8‐diazabicyclo[3.3.0]octan‐7‐ones)

The first representatives of 3,3′‐bi(2,4‐dioxa‐6,8‐diazabicyclo[3.3.0]octan‐7‐ones) have been synthesized by a reaction of glyoxal as form of 2,2′‐bi(4,5‐dihydroxy‐1,3‐dioxalane) with N,N′‐dialkylureas. Their structures have been supported by X‐ray analysis. 1,3‐Dialkylimidazolidine‐2,4‐diones (hydantoins) have been isolated as by‐products and their formation mechanism has been experimentally confirmed.     

A novel synthesis of 5‐aryl‐3‐phenylpyrazole from 2‐aryl‐3‐benzoyl‐1,1‐cyclopropanedicarbonitrile and hydrazine

A new process for synthesis of 5‐aryl‐3‐phenylpyrazole is achieved. The regioselective ring‐opening reaction of 2‐aryl‐3‐benzoyl‐1,1‐cyclopropanedicarbonitrile with hydrazine plays a crucial role in the described process.     

A simple and convenient method for the synthesis of 1‐dialkylaminocarbothioic acid S‐[(2,3‐epithio)propyl] esters

A simple and convenient method for the synthesis of 1‐dialkylaminocarbothioic acid S‐[(2,3‐epithio)propyl] ester was developed by the reaction of 1‐dialkylaminocarbodithioic acid‐sodium salt with 1‐chloro‐2,3‐epoxypropane in water‐methanol mixture at room temperature. An intermediate was isolated and characterized, based on which a possible mechanism was proposed.     

Studies with azoles and benzoazoles: A novel simple approach for synthesis of 3‐functionally substituted 3‐acylindoles

3‐Substituted acylindoles 8 are obtained via refluxing carboxylic acids with indole in acetic anhydride solutions. The formed 3‐substituted acylindole 8a is readily converted into 4‐aminopyrazol‐3‐ylindoles 20 , and into 22 . Indole reacts with chloroacetyl chloride to yield: 3‐chloroacetylindole 9 which could also be utilized for synthesis of a number of 3‐substituted indoles.     

The preparation of 3,3a,4,5‐tetrahydronaphth[1,2‐c]isoxazoles from dilithiated 1‐tetralone oxime and select aromatic aldehydes

Dilithiated 1‐tetralone oxime was condensed with several electron enriched aromatic aldehydes, such as 4‐methoxybenzaldehyde or lithiated 4‐hydroxybenzaldehyde, followed by acid cyclization to new tetrahydronaphthisoxazoles, 3,3a,4,5‐tetrahydronaphth[1,2‐c]isoxazoles, with a trans geometry of the C₃‐H and C_3a‐H protons that was confirmed by X‐ray single crystal analysis.     

Synthesis of 1‐(substituted phenylcarbonyl/sulfonylamino)‐1,2,3,6‐tetrahydropyridine‐5‐carboxylic acid diethylamides as potential anti‐inflammatory agents

Fifteen novel 1‐(substituted phenylcarbonyl/sulfonylamino)‐1,2,3,6‐tetrahydro‐ pyridine‐5‐carboxylic acid diethylamide ( 7, 15 ) were synthesized in fair to good yields via sodium borohydride reduction of the corresponding 1‐(substituted phenylcarbonyl/ sulfonylimino)‐3‐diethylcarbamoyl pyridinium ylides ( 6, 14 ) in absolute ethanol.     

Synthesis and characterization of 4‐aryl‐5‐(1‐aryl‐2‐methyl‐2‐nitropropyl)‐1,2,3‐selenadiazoles

The synthesis of a new set of selenadiazoles, 4‐aryl‐5‐(1‐aryl‐2‐methyl‐2‐nitropropyl)‐1,2,3‐selenadiazoles ( 4 ) derived from 2‐[4‐methyl‐4‐nitro‐1,3‐diarylpentylidene]‐1‐hydrazinecarboxamide ( 3 ) has been reported. THF has been found to be the solvent of choice for this reaction. Structural features of 3 and 4 have been analyzed by NMR and X‐ray techniques.     

A convenient and facile synthesis of pyridine,pyridazine, pyrimido‐[4,5‐c]pyridazine,pyrido[3,4‐c]pyridazine, 1,6‐naphthyridine and phthalazine derivatives

Ethyl 2‐arylhydrazono‐3‐butyrates 2 reacted with 2‐cyano‐N‐(4‐methylphenyl) acetamide 1a and 2‐cyano‐N‐(thiazol‐2‐yl)acetamide 1b to give the pyridinedione, 4 and pyridazine 5 derivatives in 3:1 ratio. The products 4 and 5 have been transformed into different phthalazine, pyrimido[4,5‐c]‐pyridazine, pyrido[3,4‐c]pyridazine and 1,6‐naphthyridine derivatives. The chemical structures have been confirmed by analytical and spectral analysis.     

Reaction of malonates with camphoranile synthesis of 4‐hydroxy‐2‐pyridones attached to the bornane ring system

The reaction of camphoraniles 3a,b with “magic malonates” (bis‐2,4,6‐trichlorophenylmalonates) 4a,b leads to 4‐hydroxy‐2(1H)‐pyridones attached to bornane ring system 6a‐c in good yields. Less satisfactory yields were obtained with the diethyl malonate 5b . The reaction of an excess of diethyl malonate 5 itself with 3b yields the pyrono derivative 7 , which can readily be degraded via the acetyl derivative 8 to the basic structure 9 .     

Synthesis of novel pyrazole‐linked norcantharidin derivatives of substituted aromatic amines with efficient 1,3‐dipolar cycloaddition

Highly efficient, practical and convient synthesis of fifteen compounds by the [3+2] 1,3‐dipolar cycloaddition reaction of norcantharidin derivatives of substituted aromatic amines with three hydrazines in the presence of Chloramine‐T.     

Synthesis and antimicrobial activity of 2‐(acyl or carboxyalkyl)‐3‐(H or alkyl or aryl)‐5 (or ‐6 or ‐8)‐monochloro, 7‐fluoro‐substituted‐4H‐1,4‐benzothiazines

A series of 2‐(acyl or carboxyalkyl)‐3‐(H or alkyl or aryl)‐5 (or ‐6 or ‐8)‐monochloro, 7‐fluoro‐substituted‐4H‐1,4‐benzothiazines 3a‐x were prepared to investigate their potential biological activity. In this work the 3a‐w structures are supported with physical and analytical data and the results of their in vitro antimicrobial activity against some strains Gram positive, Gram negative, and Fungi are reported. It was found that compounds 3a, 3d displayed interesting antibacterial activity, whereas compound 3f displayed interesting antifungal activity.     

One‐pot synthesis of symmetrically disubstituted 3H‐phenoxazin‐3‐ones by selective oxidative condensation with LTA

A one‐pot synthesis of some new 2,8‐disubstituted 3H‐phenoxazin‐3‐ones from 4‐substituted‐2‐aminophenols through a selective oxidative condensation by lead tetraacetate in acetic acid is described.