Pyrrole-Annulated Heterocyclic Systems. Synthesis of 2H-Pyrrolo[3,4-b][1,5]benzothiazepine 4,4-Dioxide Derivatives

Condensation of 2-nitrothiophenol with ethyl propiolate afforded 3-(2-nitrophenylthio)propenoate. Oxidation of sulfur atom to sulfone group gave ethyl 3-(2-nitrophenylsulfonyl)propenoate, which underwent condensation with tosyl methylisocyanide (TosMIC) to yield ethyl 4-(2-nitrophenylsulfonyl)pyrrole-3-carboxylate. Reduction of nitro group afforded ethyl 4-(2-aminophenylsulfonyl)-1H-pyrrole-3-carboxylate, which was cyclized to 2H-pyrrolo[3,4-b][1,5] benzothiazepin-10(9H)-one 4,4-dioxide. Similar procedure was used for the synthesis of 9,10-dihydro-10-methyl-2H-pyrrolo[3,4-b][1,5]benzothiazepine 4,4-dioxide.     

Facile synthesis of furobenzothiazepines

The reaction of methyl 5-(2-isocyanatophenylthio)-2-furancarboxylate 2 with N-methylpiperazine gave 5-(2-N-piperazinocarbamoylphenylthio)-2-furancarboxylate 3a . Furthermore, 4-N-methylpiperazinyl-2-methoxycarbonylfuro[2,3-b][1,5]benzothiazepine 4a was obtained by the Bischler-Napieralski reaction of 3a with phosphorus oxychloride in the present of phosphorus pentoxide. Three furobenzothiazepines could be obtained using the same method. Based on the pharmacological studies of these compounds, it was found that 4-morpholinyl-2-methoxycarbonylfuro[2,3-b][1,5]benzothiazepine 4b had anti-inflammatory activity similar to flufenamic acid.     

A new heterocyclic system: Imidazo[2,1-d][1,5]benzothiazepine. Its synthesis from 4-amino-2,3-dihydro-1,5-benzothiazepine

The synthesis of 4-amino-2,3-dihydro-1,5-benzothiazepine and its transformation to the new heterocycle Imidazo[2,1-d][1,5]benzothiazepine is described.     

Synthesis and structure characterization of new [1,2,4]triazolo[5,4‐d][1,5]benzothiazepine derivatives through 1,3‐dipolar cycloaddition reaction

Reaction of 1,5‐benzothiazepines 3 , obtained from chalcones 2 and o‐aminobenzenthiol, with the (phenylhydrazino) chloromethylenecarboxylates 4 in the presence of Et₃N leads to a series of new [1,2,4]triazolo[5,4‐d][1,5]benzothiazepine derivatives 5 . Their structures were established using spectroscopic methods and that of compound 5d was confirmed using X‐ray diffraction analysis. J. Heterocyclic Chem., (2011).     

Phthalazinone in Heterocyclic Synthesis: Synthesis of Some s-Triazole,s-Triazolothiadiazine,s-Triazolothiadiazine,and s-Triazolothiadiazole Derivatives as Pharmaceutical Interest

1(2H)-Oxophthalazine-2-acetic acid ethyl ester was allowed to react with various reagents under different conditions to yield compounds 2-[(4-substituted-5-mercaptotriazol-3-yl) methyl]-1 (2H)-oxophthalzines 5 and 7 which acted as starting materials for the preparation of some new s-triazolo[5,1-b][1,3]thiazine (8), s-triazolo[3,4-b][1,3,4]thiadiazine 9,12,14,20, and s-triazolo[3,4-b][1,3,4]thiadiazole 18,21 derivatives.

     

An Efficient Synthesis of 1,5-Thiadiazepines and 1,5-Benzodiazepines by Microwave-Assisted Heterocyclization

A novel and efficient method for the synthesis of substituted thiazepines and diazepines has been developed. A simple one-pot reaction of chalcones 1a–f with 1-amino-2-mercapto-5-phenyl-1,3,4-triazole and o-phenylenediamine in the presence of a catalytic amount of sodium acetate under microwave irradiation gave 2-(3,8-diphenyl-7,8-dihydro[1,2,4]triazolo[3,4-b][1,3,4]thiadiazepin-6-yl)phenoles 2a–f and 2-(2-phenyl-2,3-dihydro-1H-1,5-benzodiazepin-4-yl)phenoles 3a–f, respectively. The structure of all the synthesized compounds was elucidated on the basis of elemental analysis, IR, ¹H and ¹³C NMR, and mass spectral data.     

Microwave assisted convenient synthesis of quino[2,3-b][1,5]benzoxazepines

A convenient synthesis of quino[2,3-b][1,5]benzoxazepines from substituted 2-chloroquinoline-3-carbaldehyde and 2-hydroxy-aniline by using stable,non-toxic and inexpensive catalyst 1,8-diazabicyclo-undecan-7-ene (DBU)/silica gel is described.This method affords the quino[2,3-b][1,5]benzoxazepines under the influence of microwave irradiation (360 W) in solvent-free conditions within short reaction times (2-3 min),giving high yields of products (93-96%).     

Study of 1,3‐Dipolar Cycloaddition and Ring Contraction of New 1,4‐Phenylene‐bis[1,5]benzothiazepine Derivatives

Some 1,4‐phenylene‐bis[1,2,4]oxadiazolo‐[5,4‐d][1,5]benzothiazepine derivatives ( 4a , 4b , 4c ) were synthesized by 1,3‐dipolar cycloaddition reaction of benzohydroximinoyl chloride with 1,4‐phenylene‐bis(4‐aryl)‐2,3‐dihydro[1,5]benzothiazepine ( 2a , 2b , 2c ); meanwhile, compounds 2a , 2b , 2c also occurred ring contraction under acylating condition to obtain bis[2‐aryl‐2′‐(β‐1,4‐phenylenevinyl)‐3‐acetyl]‐2,3‐dihydro[1,5]benzothiazoles ( 3a , 3b , 3c ). The structures of some novel compounds were confirmed by IR, ¹H‐NMR, elemental, and X‐ray crystallographic analysis.     

Electron impact mass spectral fragmentation of 2a,4-disubstituted 2-chloro/2,2-dichloro-2,2a,3,4-tetrahydro-1H-azeto[2,1-d][1,5]benzothia zepin-1-ones

The mass spectrometric behaviour of nine 2a,4-disubstituted 2-chloro/2,2-dichloro-2,2a,3,4-tetrahydro-1H-azeto[2,1-d][1,5]b enzothiazepin-1-ones has been studied with the aid of mass-analysed ion kinetic energy spectrometry and accurate mass measurements under electron impact ionization. All compounds show a tendency to eliminate a neutral chlorine atom, or a chloroketene, or neutral propene, or styrene or substituted styrene molecule, plus Cl and/or H (or Cl) atom(s), to yield [M-Cl]+ ions, 2,3-dihydro-1,5-benzothiazepine derivative ions, 4,5-dihydro-5H-1,5-benzothiazepin-4-one ions which can further lose CO to give 1,4-benzothiazine ions. Both molecular ions and [M-Cl]+ ions show a tendency to eliminate an ethyl or benzyl/substituted benzyl radical to produce 2,2a-dihydro-1H-azeto[2,1-c][1,4]benzothiazin-1-one ions. The [M-Cl]+ ions could undergo rearrangement to yield 2,2a-dihydro-1H-azeto[2,1-d][1,5]benzothiazepin-1-one ions, 2,2a,3,4-tetrahydro-1H-azeto[1,2-a]quinoline ions or 1,1a,2,3-tetrahydro-azirino[2,1-d][1,5]benzothiazepine ions by loss of an ethane or a benzene/substituted benzene, a SH radical or a CO molecule. The molecular ions could also undergo rearrangement reactions to form other small fragment ions.     

Synthesis of New Tetraheterocyclic Systems by the Mixed Condensation Reactions on [1,2,4]Triazolo[4,3‐a][1,5]benzodiazepines

We report here a one step synthesis of a new series of bis‐[1,2,4‐triazolo][4,3‐a:3′,4′‐d][1,5]benzodiazepines 3a–e and [1,2,4]oxadiazolo[5,4‐d][1,2,4]triazolo[4,3‐a][1,5]benzodiazepines 5a–c by the condensation reactions of diarylnitrilimines and arylonitrile oxides. This 1,3‐dipolar cycloaddition is completely regioselective. The structure of these products has been confirmed by ¹H, ¹³C NMR and mass spectroscopic.     

Synthesis of some substituted triazolo[4,3-b][1,2,4]triazines as potential anticancer agents

The synthesis of some 3-substituted amino-6,7-diphenyl-1,2,4-triazolo[4,3-b][1,2,4]triazines (15) by cyclodesulfurisation of the corresponding N-(5,6-diphenyl-1,2,4-triazin-3-yl)-N-[substituted thio (carbamoyl)]hydrazines (3) using dicyclohexylcarbodiimid (DCC) and mercuric chloride is described. Moreover, trials to prepare 3-substituted amino-7-hydroxy-6-methyl-1,2,4-triazolo[4,3-b][1,2,4]triazines were not successful.

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Synthese einiger substituierter Triazolo[4,3-b][1,2,4]-triazine als potentielle Antikrebswirkstoffe

Zusammenfassung Es wird die Synthese einiger 3-substituierter Amino-6,7-diphenyl-1,2,4-triazolo[4,3-b][1,2,4]-triazine (15) mittels Cyclodesulfurisierung der entsprechenden N-(5,6-Diphenyl-1,2,4-triazin-3-yl)-N-[subst.thio(carbamoyl)]-hydrazine (3) unter Verwendung von Dicyclohexylcarbodiimid (DDQ) beschrieben. Versuche zur Herstellung von 3-substituierten Amino-7-hydroxy-6-methyl-triazolo[4,3-b][1,2,4]-triazinen schlugen fehl.

     

Condensed isoquinolines. 37.* Heterocyclization using 3-(arylamino)- and 3-(hetarylamino)isoquinolin-1(2H)-ones

The reaction of 3-NHR-isoquinolin-1(2H)-ones (R = Ar) with aromatic aldehydes in the presence of Me3SiCl or in acetic acid leads to the formation of derivatives of dibenzo[b,f][1, 8]naphthyridin-5(6H)- one and benzo[f]isoquino[3,4-b][1, 8]naphthyridine-5,9(6H,7H)-dione. The reaction for R = Het in the presence of Me3SiCl gives derivatives of 5H-pyrido[1',2':1,2]pyrimido[4,5-c]isoquinolin-5-one, benzo[f]isoquinoline[3,4-b][1,8]naphthyridine-5,9[6H,7H]-dione, and derivatives of new heterocyclic systems, 5H-pyrazino[1',2':1,2]pyrimido[4,5-c]isoquinolin-5-one, 5H-[1,3]thiazolo[3',2':1,2]pyrimido- [4,5-c]isoquinolin-5-one, 5-H-benzo[f]pyrazolo[3,4-b][1,8]naphthyridin-5-one, and isoquino[3,4-b]- [1,5]naphthyridin-5(6H)-one. The effect of the structure of substituent R and nature of the substituent in the benzaldehydes on the structure of the reaction products was studied.     

An improved synthesis of pyrazolo[3,4‐b][1,5]benzoxazepine, ‐benzothiazepine and ‐benzodiazepine derivatives via a convenient one‐pot synthesis

An improved and simple method for the preparation of pyrazolo[3,4‐b][1,5]benzoxazepine, ‐benzothiazepine and ‐benzodiazepine derivatives was established by the reaction of 5‐chloro‐1‐phenylpyrazole‐4‐carbaldehydes, ethyl 3‐(5‐chloro‐1,3‐diphenylpyrazol‐4‐yl)‐2‐cyanoacrylate and 1,4‐diacetyl‐3‐methyl‐2‐pyrazolin‐5‐one with o‐aminophenol derivatives and o‐phenylendiamine.     

Cycloaddition of benzoheteroazepine II Reactions and conformations of cycloadducts on1,5-benzothiazepines and 1,5-benzodiazepines with nitrile imine and nitrile oxides

Benzodiazepine and benzothiazepine derivatives have been well known as therapeutically important compounds. Four new tricyclic heterocyclic compounds, 3a,4,5,11-tetrahydro-3H-1,2,4-triazolo[4,3-d] [1, 5]benzothiazepines (3), 3a,4,5,11-tetrahydro-3H,6H-1,2,4-triazolo[4,3-d][1,5]benzodiazepine (4), 3a, 4,5,11-tetrahydro-1,2,4-oxadiazolo[4,5-d] [1,5]benzothiazepines (5, 6) and 3a,4,5,11-tetrahydro-6H-1, 2,4-oxadiazolo[4, 5-d] [ 1, 5 ] benzodiazepines (7,8), have been synthesized by 1,3-dipolar cycloaddition reactions of 2, 3-dihydro-1, 5-benzothiazepines and 2, 3-dihydro-1H-1, 5-benzodiazepine with benzonitrile N-phenylimine and benzonitrile oxides, respectively. The conformations of some cycloadducts and cycloaddition mechanism are described.     

Ionic Liquid-Mediated Facile Synthesis and Antimicrobial Study of Thiazolo [2,3-b]Benzo[h]Quinazolines and Thiazino[2,3-b] Benzo-[h]Quinazolines

Abstract

8-Methoxy-4-phenyl-3,4,5,6-tetrahydrobenzo[h]quinazoline-2(1H)-thione, obtained by the condensation of 2-benzylidene-6-methoxy-3,4-dihydronapthalene-1(2H)-one with thiourea, on reaction with chloroacetic acid and 3-chloropropanoic acid in the presence of the ionic liquid N-methylpyridinium tosylate furnishes 3-methoxy-7-phenyl-7,10-dihydro-5H- benzo[h]thiazolo[2,3-b]quinazoline-9(6H)-one and 3-methoxy-7-phenyl-5,6,10,11-tetrahydro- benzo[h][1,3]thiazino[2,3-b]quinazoline-9(7H)-one. Further, condensation of the thione with 1,2-dibromoethane and 1,3-dibromopropane yields 3-methoxy-7-phenyl-6,7,9,10-tetrahydro-5 H-benzo[h]thiazolo[2,3-b]quinazoline and 3-methoxy-7-phenyl-5,6,7,9,10,11-hexahydrobenzo [h][1,3]thiazino[2,3-b]quinazoline respectively. Arylidene derivatives have been obtained by two routes. The structures of the cyclized compounds have been established on the basis of elemental analysis and spectroscopic data. The synthesized compounds were screened for antimicrobial activity. Some of the compounds showed promising antimicrobial activities.     

Electron Ionization Mass Spectra of Organophosphorus Compounds Part I: The Mass Fragmentation Pathways of Cyclic α-Aminophosphonates Monoester Containing 1,2,4-Triazinone Moiety

Abstract

The electron impact induced fragmentation reactions of 3-(4-chlorophenyl)-3,4- dihydro-2-ethoxy-2-oxido-7-methyl-2H,6H-[1,2,4]triazino[4,3-e][1,4,5,2]thiadiazaphosphin in-6-one (1), 3,7-dimethyl-2-ethoxy-2-oxido-1,2,3,4-tetrahydro-6H-[1,2,4]triazino[4,3-b][1,2,4,5]triazaphosphinin-6-one (2), and 9-amino-3,7-dimethyl-4-ethoxy-4-oxido-2,3,4,9-tetrahydro-8H-[1,2,4]triazino[3,2-c][1,2,4,5]triazaphosphinin-8-one (3) are presented and compared. The 1,2,4-triazine rings have almost identical fragmentation routes. The 1,2,4-triazine rings are rather stable relative to the phosphorus rings. Therefore, fragmentation of the phosphorus rings is more favorable for the compounds than the stable 1,2,4-triazine rings.     

Synthesis of 6H-indolo[2,3-b][1,6]naphthyridines and related compounds as the 5-Aza analogues of ellipticine alkaloids

Treatment of 2-(1-alkynyl)phenyl isocyanates 6 with the iminophosphorane 14 produced in situ the benzoenynyl carbodiimides 15. Thermolysis of 15 under refluxing p-xylene furnished the 6H-indolo[2,3-b][1,6]naphthyridines 5, which could be regarded as the 5-aza analogues of ellipticine alkaloids. Similarly, condensation of 6 with the iminophosphorane 20 led to the formation of the 6H-indolo[2,3-b][1,5]naphthyridines 25 as the major isomer and the 10H- indolo[2,3-b][1,7]naphthyridines 26 as the minor isomer. The indolonaphthyridines 32, 33, and 34 having a methoxyl substituent were likewise synthesized. Treatment of the diisocyanate 43 with 2 equiv of the iminophosphorane 7 furnished 45 having two indoloquinoline units incorporated in a seven-fused-ring system.     

New heterocyclic sym-triazolopyrimidinium systems — Quinoline,pyridazine, and phthalazine derivatives

Pyrimido[1′,2′:1,5]-sym-triazolo[4,3-b]pyridazinium, pyrimido[1′,2′:1,5]-sym-triazolo-[4,3-b]phthalazinium, and pyrimido[1′,2′:1,5]-sym-triazolo[4,3-a]quinoliniumsalt derivatives were obtained by condensation of 3-amino-sym-triazolo[4,3-b]pyridazinium, 3-amino-sym-triazolo[3,4-a]phthalazinium, and 1-amino-sym-triazolo[4,3-a]quinolinium salts with β-diketories and 1,1,3,3-tetraethoxypropane. The structures of the reaction products were confirmed by the P MR spectra.     

Investigation of the Reaction of Chloroacetyl Chloride with 1,5-Benzothiazepines: Selective Synthesis of Azeto[2,1-d][1,5]benzothiazepines by Green Chemical Methods and Their Biological Activity

An efficient and exclusive synthesis of the tricyclic azeto[2,1-d][1,5]benzothiazepine ring system has been developed. By use of microwave irradiation in the presence of basic alumina, the reaction time has been brought down from hours to minutes with improved yields in comparison to conventional heating. Antimicrobial screening of the synthesized compounds has shown promising activity.     

Tetracyclic Systems: An Efficient and Rapid Synthesis of New Pyrrolothieno[1,3]Thiazocines

The Pyrrolo[2,1-b]thieno[2,3-e][1,3]thiazocinediones (6a,b) resulting from a few known eight membered ring cyclization were successfully described via the Friedel-Crafts cyclodehydration of the appropriates 1-(thien-2′-ylmethyl)-2-pyrrolidinone-5-thioglycolic acids (5a,b).