Nasr K. Mohamed

REACTION OF DIIMINES AND BENZYNE

Abstract The reaction between benzyne and the Schiff bases 1a,b and 15a,b leads to the 1,4-bis(2‵-substituted acridin-10-yl)benzene 4a,b , the N-phenylarylamines 10a,b and the 10-(4‵-formylphenyl)-substituted acridines 11a,b (from 1a,b ) and the 2-substituted acridine-10-carboxyaldehyde 18a,b (from 15a,b ). Cyclohexyl (4-cyclohexyliminomethylbenzylidine)amine 1c reacts with benzyne by an ene-reaction to give cyclohexenyl[(4-cyclohexyliminomethylphenyl)benzylidine]amine 14 .

A novel synthesis of heterocycles from thiocarbohydrazides

SummaryThe reaction of thiocarbohydrazides1a and thiocarbazones1b with tetracyanoethylene (TCNE) afforded the thiazol, thiadiazole, thiazine, and thiadiazepine derivatives4–7. 2-Dicyanomethyleneindane-1,3-dione (CNIND) reacted with1a,b to give aminoindenopyrazolopyridazinone (12) and phenyl-1,2,3,4-tetraazacyclopentafluorene (13). The indazole and oxathiadiazole derivatives17 and19 were formed during the reaction of1b with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDO). 6,7-Dichloro-5-phenylpyrazolophthalazinol (21) was obtained from the reaction of1b with 2,3,5,6-tetrachloro-1,4-benzoquinone (CHL-p). The oxidative cyclization of thiodicarbazones2a–d with the above acceptors afforded the thiadiazole and thiadiazine derivatives8 and10.ZusammenfassungDie Reaktion der Thiocarbohydrazide1a und der Thiocarbazone1b mit Tetracyanoethylen (TCNE) ergab die Thiazol-, Thiadiazol-, Thiazin- und Thiadiazepinderivate4–7. 2-Dicyanomethylenindan-1,3-dion (CNIND) liefert mit1a,b Aminoindenopyrazolopyridazinon (12) und Phenyl-1,2,3,4-tetraazacyclopentafluoren (13). Die Indazol- und Oxathiadiazolderivate17 und19 wurden durch Reaktion von1b mit 1,3-Dichlor-5,6-dicyano-1,4-benzochinon (DDQ) gebildet. 6,7-Dichlor-5-phenylpyrazolophthalazinol (21) wurde aus1b und 2,3,5,6-Tetrachlor-1,4-benzochinon (CHL-p) erhalten. Die oxidative Cyclisierung der Thiodicarbazone2a–d mit den obengenannten Akzeptoren ergab die Thiadiazol- und Thiadiazinderivate8 und10.

Novel heterocyclics from 3-substituted-5H-1,2,4-triazino-[5,6-b]indoles and π-acceptors

Abstract The reaction of 1,2,4-triazino[5,6-b]indole-3-thione 1 with tetracyanoethylene (TCNE) afforded the disulfide 6 the tricyanovinylation product 8 and thiazolotriazinoindole 11. 3-Aryl-5H-1,2,4-triazino[5,6-b] indoles 2a,b reacted with TCNE to give pentacyanopropene 12 and 3-aminotriazinoindole derivatives 14a,b. 3-Hydrazino-5H-1,2,4-triazino[5,6-b]indole 3 reacted with TCNE, dicyanomethyleneindane-1,3-dione (CNIND)and 2,3-dicyano-1,4-naphthoquinone (DCNQ)to form triazolotriazinoindoles 17 and the triazepinotriazinoindoles 16,24 and 26. The reaction of 3, with chlorinated quinones gave the quinazolinetriones 21–23.

Chemical interactions between 2-mercaptobenzazoles and π-acceptors

Summary2-Mercaptobenzazoles (1a–c) interact with several π-acceptors such as tetracyanoethylene (TCNE) 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), 2,3,5,6-tetrachloro-1,4-benzoquinone (CHL) dicyanomethyleneindane-1,3-dione (CNIND), 2,3-dicyano-1,4-naphthoquinone (DCNQ), 9-dicyanomethylene-2,4,7-trinitrofluorene (DTF), and 2,3-dichloro-1,4-naphthoquinone (DCHNQ)via the formation of charge-transfer (CT) complexes to yield various heterocyclic compounds.ZusammenfassungDie 2-Mercaptobenzazole1a–c reagieren mit verschiedenen π-Akzeptoren wie Tetracyanoethylen (TCNE), 2,3-Dichlor-5,6-dicyano-1,4-benzochinon (DDQ), 2,3,5,6-Tetrachlor-1,4-benzochinon (CHL), Dicyanomethylenindan-1,3-dion (CNIND), 2,3-Dicyano-1,4-naphthochinon (DCNQ), 9-Dicyanomethylen-2,4,7-trinitrofluoren (DTF) und 2,3-Dichlor-1,4-naphthochinon (DCHNQ) unter Ausbildung von charge transfer — Komplexen (CT) zu heterocyclischen Verbindungen.

Rhodanine in Fused-Heterocycles Syntheses

The reaction of 3-aminothiazolidine-2-thione-4-one (3-aminorhodanine, 1) with some π-deficient compounds afforded three types of products: bicyclic noncondensed derivatives such as bis(3-aminothiazole-2-thione-4-one), the condensation product 2-(3-amino-2-thioxothiazolo)-1,3-indanedione, as well as the fused heterocyclic compounds thioxothiazolo[3,4-c]oxadiazine, furo[2,3-b]thiazole, thiazolo[3,4-c]benzoxadiazine, and naphthoquinothiazolo[3,4-c]oxadiazine.

SYNTHESIS OF SOME FUSED HETEROCYCLES CONTAINING 2,5-DISUBSTITUTED-1,3,4-THIADIAZOLES

Abstract The synthesis of some novel fused heteracyclic compounds such as 1,3,4-thiadiazolo[3,2-b]diazepine, indenothiadiazolopyrimidine, indenocyclopentathiadiazole and naphthoquinoimidazolothiadiazole derivatives containing 1,3,4-thiadiazole ring system have been reparted.

REACTIONS OF BENZIMIDAZOLYL-ACETONITRILE AND METHANETHIOL WITH ELECTRON DEFICIENT COMPOUNDS

Addition of l//-benzimidazole-2-acetonitrile I and benziimidazole-2-ylmethanethiol 2 to some π-acceptors such as tetracyanoethylene (TCNE), £-chloranil (CHL-g). o-chloranil (CHL-o), 2,3-dichloro-5.6-dicyano-l,4-benzoquinone (DDQ). 2,3dichloroand 2.3-dicvano-1,4-naphthoquinones (DCHNQ and DCNQ) and dicynomethyleneindane-1.3-dione (CNIND) gave pyrido-, indolo-, naphthoquinopyrrolo-, thiazino-. naphthoquinothiazino[1.2-o]benzimidazole as well as pyridazino[l,2ojdibenzimidazole derivatives.

NOVEL HETEROCYCLES FROM CREATININE

Creatinine 1 interacts with some π-deficient compounds such as tetracvanoethylene. 2.3dichioro-5.6-dicyano-1.4-benzoquinone. 2.3.5.6-tetrachloro-l .4-benzoquinone. 2.3-dichloro-l .4naphthoquinone and 2.3-dicyano-1.4-naphthoquinone to give imidazolidinone. imidazolinyl-azomethine. furobisimidazolidine. naphthoimidazoimidazolidine and benzobisimidazoimidazo-lidines derivatives.

NOVEL HETEROCYCLIZATION OF N-SUBSTITUTED THIOSEMICARBAZIDES

Abstract N-Phenyl-and N-benzyl thiosemicarbazide 1a,b reacted with tetracyanoethylene (TCNE) viacharge-transfer (CT) complex formation giving thiadiazepine and thiadiazole derivatives (6. 7 and 16). On mixing 1a,b with 2.3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), oxathiadiazoles and dithiadiazole derivatives (20 and 24) were formed. The mechanism of the formation of these products has been elucidated.

Synthesis of 1,3-thiazolidin-4-ones; reactivity of the thiosemicarbazone function towards dimethyl acetylenedicarboxylate

Aryl thiosemicarbazones react rapidly in a facile procedure with dimethyl acetylene-dicarboxylate to give substituted (ylidene) hydrazono(4-oxothiazolidin-5-ylidene) acetates in high yields. The synthesised compounds were characterised by spectroscopic methods and the structures confirmed by single crystal X-ray crystallography. Several mechanistic options involving nucleophilic interaction are presented.