A. A. Geies

Synthesis, magnetic properties and theoretical calculations of novel nitronyl nitroxide and imino nitroxide diradicals grafted on terpyridine moiety

Abstract The synthetic route based on Stille coupling between tributyltinpyridyl derivatives and bromo substituted mono- and dipyridyl-carbaldehyde is used for the synthesis of 5,5″-diformyl-2,2′:6′,2″-terpyridine ( 8 ). A sequence of Ullman coupling with 2,3-bis(hydroxylamino)-2,3-dimethylbutane followed by oxidation under phase transfer conditions affords either 5,5″-Bis(1-oxyl-3-oxo-4,4,5,5-tetramethylimidazolidin-2-yl)2,2′:6′,2″-terpyridine ( 10 ) (diNN-Terpy) or the related 5,5″-Bis(1-oxyl-4,4,5,5-tetramethylimidazolidin-2-yl)2,2′:6′,2″-terpyridine ( 11 ) (diIN-Terpy), where both biradicals display clear intramolecular ferromagnetic interaction between the single spin units as evidenced by ESR spectroscopy. Quantum chemical calculations (ROHF/AM1) are performed showing the triplet ground-state for both 10 and 11 radicals.

SYNTHESIS AND REACTIONS OF SOME THIENO[2,3-d]PYRIMIDINE DERIVATIVES

Abstract 5-Cyano-4-oxo-6-phenyl-2-thioxo-1,2,3,4-tetrahydropyrimidine (I) reacts with P2S5 in pyridine to give pyrimidine-2,4-dithione (II). Further reaction of II with ethyl chloroacetate, chloroacetanilide, phenacyl bromide, bromoacetone and chloroacetonitrile gave the corresponding thieno[2,3-d]pyrimidine derivatives (III-VI). Interaction of compound IVa with hydrazine hydrate in ethanol or diluted ethanol gave the hydrazide and hydrazino derivatives (VII, IX), which reacted with aromatic aldehydes to give the corresponding hydrazones (VIIIa-c, Xa-c ). Alkaline hydrolysis of IV, using KOH gave the acid XI with extrusion of thioglycolic acid.

Synthesis of some thiazolo[3,2-a]pyrimidines

Abstract 2-Acetyl-6-cyano-7-ethyl-3-methylthiazolo[3.2-a]-pyrimidine-S-one (3) prepared by reaction of compound (1) with 3-chloropentan-2.4-dione followed by ring closure, was used as starting material to synthesise other heterocyclic compounds. The acetyl compound (3) was easily condensed with different amines to produce the imines (4–8). or the corresponding chalcone (9) when allowed to react with an aromatic aldehyde in presence of zinc chloride. Coupling of compound (3) with benzene diazonium chloride gave the phenylazo derivative (10). When compound (4) was treated with a-haloketones or a-haloesters, the thiazoline or thiazolidine compounds (11–15) were produced. Compound (15) was condensed with aromatic aldehydes to give the corresponding arylidene-derivatives (16a–c). Finally the chalcone (9) was reacted with hydrazine hydrate, phenyl hydrazine and hydroxyl amine to give pyrazolo and isoxazole compounds (17–19) respectively.

SYNTHESIS AND SOME REACTIONS OF PYRROLO[1″,2″:1′,6′]PYRAZINO-[2′, 3′: 4, 5]THIENO[2, 3-b]QUINOLINES; A NEW FUSED PYRAZINE RING SYSTEMS

Abstract Ethyl 3-amino-4-(4-chlorophenyl)-5, 6, 7, 8-tetrahydrothieno[2, 3-b]quinoline-2-carboxylate (1) was converted into the corresponding 3-(1-pyrrolyl) derivative 2. Various derivatives of 2 were prepared. The synthesis of the title compounds and other related heterocyclic systems are reported.

SYNTHESIS AND ANTIMICROBIAL ACTIVITY OF SOME NEW PYRAZOLES AND THIEN0[2,3-c]PYRAZOLES

Abstract Starting with 5-chloro-1,3-diphenyl- 1H-pyrazole-4-carboxaldehyde (1), both of (4-cyano-1,3-diphenyl-1H-pyrazol-5-ylthio) acethydrazide (6) and 1,3-diphenyl- 1H-thieno[2,3-c] pyrazole-5-carbohydrazide (15) were synthesized. These hydrazides (6 and 15) were used as key intermediates in the synthesis of other new pyrazoles 7–12 and thieno[2,3-c]pyrazoles 16–30 respectively. Some of the prepared compounds were screened in vitro for their antibacterial and antifungal activity.

Synthesis and antimicrobial activity of new heterocyclic compounds containing thieno[3,2-c]coumarin and pyrazolo[4,3-c]coumarin frameworks

Reaction of 4-chlorocoumarin-3-carbonitrile with ethyl thioglycolate and ethyl glycinate hydrochloride leads to a series of title products. Hydrazinolysis of amino thienocoumarin carboxylate afforded the hydrazino derivative which underwent various reactions to build new heterocyclic rings containing thienocoumarin moiety. Chloro acetylation of aminoester compound afforded the chloro acetyl amino which underwent nucleophilic substitution reactions with various amines. The following treatment with formaldehyde under Mannich conditions afforded the corresponding imidazo derivatives. Reaction of chloroacetylamino with potassium thiocyanate yielded ethylpyrimidothieno coumarin sulfanylacetate which was used as a versatile precursor for synthesis of other heterocycles. On the other hand, reaction of chloro coumarin carbonitrile with hydrazine gave the aminopyrazolocoumaine which reacted with bifunctionally compounds to give the substituted pyrimido derivatives. Diazotization and coupling of aminopyrazole with ethylcyanoacetate yielded ethylaminotriazinopyrazolocoumarine carboxylate. Several of the compounds obtained demonstrated considerable antifungal and antibacterial activity in the in vitro test systems.

CHEMISTRY AND CYCLIZATION REACTIONS OF 2-METHYLPYRIMIDO THIENOQUINOXALINE DERIVATIVES, PART III

Abstract Treatment of 2-methyl-pyrimido[4′,5′:4,5]thieno[2,3-b]-quinoxalin-4-one (2) with a mixture of phosphorous oxychloride phosphorous pentachloride affords 4-chloroderivatives (3). Treatment of 2 with phosphorous pentasulphide give the 4-thione derivative (4) which reacts with methyl iodide to yield the 4-methylthioderivative (6). Treatment of 3 with different nucleophiles, namely; hydrazinehydrate, aniline and dimethylamine, produce, 4-hydrazino-(5); 4-anilino-(7) and 4-dimethylamino-(8) derivatives, respectively. However, treatment of 3 with ethylglycinate gives 5-methyl imidazo[1″,2″: 1′,6′]pyrimido-[4′,5′:4,5]thieno[2,3-b]quinoxaline-3-one (9). 4-Hydrazino-2-methylpyrimido[4′,5′:4,5]thieno[2,3-b]quinoxaline (5) was condensed with p-substituted benzaldehydes to produce the corresponding hydrazones (10a–c). Treatment of 5 with acetic anhydride affords the hydrazinotriacetate compound (11), while with phthalic anhydride affords the corresponding 2-(pyrimido-thienoquinoxalin-4-yl)-dihydro-1,4-phthala...

Synthesis of new triazoloquinoxalines, pyrroloquinoxalines, and pyrimidopyrroloquinoxalines

SummaryWhen 2-hydroxyquinoxaline-3-carboxamide (1) was reacted with POCl3 inDMF, 2-chloro-3-dimethylaminomethylenecarboxamide (2) was obtained. The chloro compound2 was reacted with thiourea and hydrazine hydrate to give the corresponding mercapto and hydrazino derivatives3 and8, respectively. On the other hand, 2-chloroquinoxaline-3-carbonitrile (13) reacted with ethyl glycinate to the glycinate derivative14 which was cyclized to pyrroloquinoxaline15 by heating with sodium ethoxide. Pyrimidopyrroloquinoxaline derivatives16 and17 were obtainedvia the reaction of15 with formamide and phenyl isothiocyanate, respectively.ZusammenfassungWenn man 2-Hydroxychinoxalin-3-carboxamid (1) mit POCl3 inDMF reagieren läßt, erhält man 2-Chlor-3-dimethylaminomethylencarboxamid (2). Die Chlorverbindung2 wurde mit Thioharnstoff und Hydrazinhydrat zu den entsprechenden Mercapto- und Hydrazinderivaten3 und8 umgesetzt. Aus 2-Chlorchinoxalin-3-carbonsäurenitril (13) und Ethylglycinat erhält man14, das durch Erhitzen mit Natriumethylat zum Pyrrolochinoxalin15 cyclisiert wurde. Die Pyrimidopyrrolochinoxalinderivate16 und17 wurden durch Reaktion von15 mit Formamid bzw. Phenylisothiocyanat erhalten.

CHEMISTRY AND CYCLIZATION REACTIONS OF THIENOQUINOXALINE DERIVATIVES: PART I

Abstract Reaction of 2(1H)quinoxalinethione-3-carbonitrile 1 with alkyl or aralkyl halides, chloroacetic acid, ethyl chloroacetate, or N-phenylchloroacetamide in ethanolic sodium acetate solution gives the corresponding 3-thioethers of 1. Treatment of 3 with acetic anhydride gives the dimesoionic thiazolo[3′,4′-c]-2-cyanoquinoxaline, 4. Treatment of 6 or 10 with ethanolic sodium ethoxide solution gives the cyclization products, ethyl-3-aminothieno[2,3-b]quinoxaline-2-carboxylate 7 or 3-phenylcarboxamide 11 substituents respectively. Treatment of 11 with carbon disulfide/ethanolic potassium hydroxide soution gives 3-phenylpyromido[4′,5′:4,5]thieno[2,3-b]quinoxaline-4-one-2-thione 12 which is also produced by treatment of 7 with phenyl isothiocyanate in dry pyridine. Compound 11 cyclizes on treatment with benzoyl chloride, acetic anhydride, phenyl isothiocyanate, ethyl chloroformate and/or nitrous acid, to produce the corresponding pyrimidothienoquinoxalines 14–17 and [1,2,3] triazinothienoquinoxaline 18 de...

Synthesis and Reactions of Some New Thienopyrimidines

4-Methyl-6-mercapto-2-phenylpyrimidine-5-carbonitrile ( 1 ) was reacted with different halo compounds, namely ethylchloroacetate, chloroacetone, bromoacetanilide, p-chlorobromoacetanilide, and p -methoxy chloroacetanilide in ethanol in the presence of sodium acetate yielded the corresponding S-alkylated derivatives ( 2a-e ). The latter compounds underwent cyclization into thienopyrimidines ( 4a-e ) upon treatment with sodium ethoxide in ethanol. The reaction of ( 4a ) with hydrazine hydrate led to the formation of 5-amino-4-methyl-2-phenylthieno[2,3-d]pyrimidine-2-carbohydrazide ( 5 ). Compound ( 5 ) was reacted with a variety of reagents to produce other new thienopyrimidines as well as oxadiazolylthienopyrimidines ( 6, 11 ).