Aboul-Fetouh E. Mourad

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 .

Microwave assisted synthesis of triazoloquinazolinones and benzimidazoquinazolinones

Background Benzimidazoquinazolinones and related quinazolines are classes of heterocycles that are of considerable interest because of the diverse range of their biological properties. Although numerous classes of quinazolines have been conventionally synthesized, their syntheses have been suffered due to the multiple steps that sometimes have described in their preparation and also their chemical transformations that have been taken hours or even days to be completed. However, microwave energy can offer numerous benefits for performing synthesis of organic compounds including reduced pollution, increased reaction rates, yield enhancements, and cleaner chemistries. Results Synthesis of a series of triazoloquinazolinones and benzimidazoquinazolinones has been achieved under microwave irradiation. The products were obtained in nearly quantitative yields within few minutes during the reaction of aromatic aldehydes with 5-amino-1(H)-1,2,4-triazole (or 2-aminobenzimidazole) and dimedone in DMF. Conclusion Microwave irradiation can be used as a facile and general method for the construction of a wide variety of triazoloquinazolinones and benzimidazoquinazolinones. The reaction involves a three component condensation (with potential for combinatorial work) being carried out with almost productive yields by microwave irradiation and considerably shortened reaction time.

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.

New cycloaddition reactions of some ethenyl and ethinyl[2.2]paracyclophanes with some dienophiles

Abstract 4-Ethenyl[2.2]paracyclophane ( 1 ), 4,12-, ( 13 ), 4,15-, ( 16 ) and 4,16-diethenyl[2.2]paracyclophane ( 18 ) as well as, 4-ethinyl-[2.2]paracyclophane ( 20 ) undergo[2+2]cycloaddition reactions with tetracyanoethylene (TCNE). These reactions involve the formation of a charge-transfer complex as an initial step. With 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ), bromanil (BRL) as well as 4-phenyl-1,2,4-triazoline-3,5-dione and 4-ethenyl[2.2]paracyclophane ( 1 ) as the diene, [2+4]cycloadditions took place. The reaction between 4,12-, ( 13 ), 4,15-, ( 16 ) and 4,16-, diethenyl[2.2]paracyclophane ( 18 ) and TCNE are influenced by the transannular electronic interactions.

SYNTHESIS OF PYRIDAZINE AND 1,3-THIAZINE DERIVATIVES VIA CT-COMPLEXATION BETWEEN THIOSEMICARBAZIDES AND TETRACYANOETHYLENE

Abstract Intermolecular charge transfer (CT) complexes of aromatic aldehyde thiosemicarbazones with some π-acceptors such as 7,7,8,8-tetracyanoquinodimethane, 2-(dicyanomethylene)indane-1,3-dione and 9-dicyanomethylene-2,4,7-trinitrofluorene have been studied spectrophotometrically. Aromatic aldehyde thiosemicarbazones, and thiosemicarbazide reacted with tetracyanoethylene via CT-complex formation to give 1,3-thiazine and pyridazine derivatives.

New reaction of ethenetetracarbonitrile with N-arylisoindolines

N-Arylisoindolines 1a - i react with ethenetetracarbonitrile 2 in aerated benzene by formation of (3-(2-aryl-3-dicyanomethylene- 2,3-dihydro-1H-isoindol-1-ylidene)-2-aryl-2,3-dihydro-1H-isoindol-1-ylidene)propanedinitriles 8a- i (20 - 36%), N-aryl-3-dicyano- methylene-isoindol-2-ones 9a - i (15 - 21%) and N-arylphthalimides 10a- i (4- 9%) as well as 1,1,2,2-tetracyanoethane 11 (35 - 55%). The structure of 8d has been unambiguously confirmed by a single crystal X-ray structure analysis. A rationale for the formation of products 8 - 11 is presented. q 2003 Elsevier Science Ltd. All rights reserved.

π-π Molecular complexes with nitrones, II. Complexation between heterocyclic nitrones and tetracyanoethylene as well as 1,4-benzoquinones

Characteristic charge-transfer absorption bands of some heterocyclic nitrones as electron donor with tetracyanoethylene, 2,3-dichloro-5,6-dicyanobenzoquinone and chloranil as electron acceptor have been measured in methylene chloride solution. The stoichiometry, apparent formation constants and transition energies of the charge-transfer complexes formed as well as the effect of solvent and the stability of these complexes are discussed.

Life Span Extension of Caenorhabditis elegans by Novel Pyridoperimidine Derivative

Zwitterions formed from the addition of triphenylphosphine to dialky acetylene-dicarboxylates attack the nucleus of both 1H-perimidine (1) and 1H-benzo[d]imidazole (9) to form novel pyrido[1,2,3-cd]perimidine and imidazo[4,5,1-ij]quinoline derivatives in moderate yields (64–72%). The biological activity of the products has been studied. Compound 3a was found to extend life span of wild type Caenorhabditis elegans under standard laboratory conditions. Both heat stress and induced chemical stress resistance of wild type C. elegans were improved in a reverse dose-dependent manner due to 3a treatment. In addition, treatment of worms with compound 3a significantly attenuated the formation of advanced glycation end products in a reverse dose-dependent manner.