M. S. Abbady

SYNTHESIS AND SOME REACTIONS OF THIENO[2,3-c]PYRIDAZINE DERIVATIVES AND THEIR ANTIBACTERIAL ACTIVITY

Abstract The title compounds (4a-f) were prepared by S-alkylation of 4-cyano-5,6-difur-2′-yl-2H-pyridazine-3-thione (2) and subsequent cyclization in ethanol in the presence of potassium carbonate. Reaction of o-disubstituted thienopyridazines (4a-d) with different reagents afforded tricyclic compounds namely, imidazothienopyridazine (5), pyridazinothienooxazine (6) and pyridazinothienopyrimidines (7–9). Most of the prepared compounds exhibited pronounced antibacterial activity.

SYNTHESIS AND REACTIONS OF SOME THIENOPYRIDINE DERIVATIVES

Abstract Substituted thieno[2,3-b]pyridines (VIII-XII) were prepared by ring closure of the corresponding S-alkylated derivatives (II-VI). Thieno[2,3-b]pyridine-2-carbohydrazide XIII was interacted with some reagents afforded the expected pyridothienopyrirnidines (XIV-XVI). Also, the carboazide XVII undergo Curtius rearrangement giving imidazolothienopyridine (XVIII). The carboxarnide derivatives (X-XII) interacted with CS2 giving pyridothienopyrirnidines (XX-XXII), while interaction with nitrous acid, pyridothienotriazines (XXIII-XXV) were produced.

Synthesis of Pyrrolo[1′,2′:1′,2′]Pyrazino-[6′,5′:4,5]Thieno[2,3-c]Pyridazine Derivatives and Related Pentacyclic Heterocycles

Abstract Ethyl-5-amino-3,4-diphenylthieno[2,3-c]pyridazine-6-carboxylate(1) was converted into ethyl 3,4-diphenyl-5-(1-pyrrolyl)-thieno[2,3-c]pyridazine-6-carboxylate(2). Several derivatives of the latter compound have been synthesized. Also, the synthesis of 3,4-diphenylpyrrolo[1″,2″:1′,2′]pyrazino[6′,5′:4,5]-thieno[2,3-c]pyridazines and other related fused heterocycles are described.

SOME REACTIONS OF 3-AMINO-2-CARBOETHOXY-4,6-DIMETHYLTHIENO[2,3-b]-PYRIDINE. SYNTHESIS OF SOME NEW THIENOPYRIDOPYRIMIDINES

Abstract Thienopyridine oxazinone (1) has been prepared and explored as a precursor by its reaction with some reagents namely, ammonium acetate, aliphatic amines, aromatic amines, hydrazine hydrate, thiosemicarbazide, and ethyl glycinate to give pyridothienopyrimidines (11-VII). The pyrimidinone compound (11) was converted to the 4-chloro derivative (X) by its reaction with excess POCl3 Interaction of the 4-chlorocompound (X) with some reagents namely, hydrazine hydrate, methyl amine, aniline, sodium thiophenolate, ethyl glycinate, thiosemicarbazide and thiourea, yielded pyridothieno-pyrimidine derivatives (XI-XVII) substituted at 4-position, respectively.

PYROLYSIS OF ARYL DESYL SULFIDE

Abstract Phenyl desyl sulfide on pyrolysis by heating at 250°C for 15 hour, gives H2S, benzaldehyde, benzil, bibenzyl, stilbene, thiophenol, diphenyl sulfide, thianthrene and 2,3,4,5-tetraphenylthiophene. Analogous results were also obtained on pyrolysis of p-tolyl desyl sulfide under the same conditions in addition to H2O, p-ditolyl sulfide, thio p-cresol, p-bitolyl and 2-phenylbenzo[b]thiophene. The observed results has been interpreted in terms of a free radical mechanism involving homolysis of C[sbnd]S bond.

Synthesis and biological activity of some new pyridines, pyrans, and indazoles containing pyrazolone moiety

Cyclocondensation reactions of 3-phenyl-1-(3-methyl-5-oxo-1-phenyl-2-pyrazolin-4-yl) prop-2-en-1-one (2) with active methylene reagents such as ethyl cyanoacetate, malononitrile, ethyl acetoacetate, and acetoacetanilide afforded pyrazolinyl pyridine derivatives (3 and 12), pyrazolinyl pyran derivative (9), and pyrazolinyl cyclohexene derivatives (10 and 11). Reaction of 11 with hydrazines and hydroxyl amine led to the formation of indazole derivatives (13 and 14), and benzisoxazole derivative 15. Also, reaction of 9 with different reagents gave pyrano[2,3-d][1,2,3]triazine (19) and pyrano[2,3-d]pyrimidine derivatives (20 and 21). The anti-inflammatory, analgesic, and antimicrobial activities of these compounds were determined. Compounds 13 and 14 showed good anti-inflammatory activity in comparison with the standard indomethacin, whereas compounds 4, 7, and 12 showed higher analgesic activity than the reference aspirin drug. In addition, compounds 7, 11, and 15 exhibited broad spectrum activities against all bacterial and fungal species tested.Graphical Abstract

Synthesis and some reactions of arylpyridylsulfide derivatives

Abstract The title compound (I) was prepared from the reaction of 2-chloro-3-cyano-4,6-dimethylpyridine and 4-bromonitrobenzene in aqueous sodium sulfide solution. Condensation of I with aromatic aldehydes, 2-methyl benzoxazin-4-one, azalactone and succinic anhydride afforded the expected products (IV, VI, VIII and XV). Coupling of diazotized I with active methylene compounds gave the corresponding hydrazones Xa,b. Cyclization of hydrazone Xa with AICl3 gave the cinnoline derivative XII, which condensed with phenylhydrazine to give the pyrazolocinnoline derivative XIII. Oxidation of some of the prepared sulfides with H2O2 in AcOH afforded the corresponding sulfones.

SYNTHESIS OF DIARYLSULPHIDES AND DIARYLSULPHONES CONTAINING PYRAZOLINE, ISOXAZOLINE, PYRIMIDINE AND CONDENSED PYRIDAZINE MOIETIES

Abstract Arylhydrazones 2a-c obtained by the reaction of diazotized 4-amino-4′-nitrodiaryi sulphide (1) with active methylene compounds i.e. ethyl acetoacetate, acetylacetone and diethyl malonate are condensed with hydrazines, hydroxylamine, urea and thiourea to give the corresponding pyrazolines (3, 4, 8, 9, 13), isoxazolines (5, 10) and pyrimidines (6, 7, 11, 12, 14, 15). Intramolecular cyclization of arylhydrazones 2a, c with AlCl3 in chlorobenzene yielded the cinnoline derivatives (16, 17). Reaction of cinnoline derivative (16) with hydrazines afforded the corresponding pyrazolo[4,3-c]cinnoline derivatives (18, 19). Oxidation of some of the prepared sulphides with H2O2/AcOH at room temperature gave the corresponding sulphones (20-30).

SYNTHESIS OF NEW RING SYSTEMS: ISOMERIC 1,2,4-TRIAZOLOPYRIMIDO [4″,5″:4′,5′]THIENO[3′,2′:5,6]PYRIDO[3,2C]CINNOLINES AND OTHER RELATED SYSTEMS

3-Amino-2-Cyano-4-(p-tolyl)thieno[3′,2′:5,6]pyrido[3,2-c]cinnoline 1 underwent ring closures with formamide and carbon disulphide to afford pyrimidothienopyridocinnaline 2 and its pyrimido-9,11-thione derivative 3, respectively. Treatment of 1 with triethylorthoformate followed by hydrazine hydrate produced 10-amino-11-imino-pyrimido system 5, which in turn reacted with triethylorthoformate, acetic acid, carbon disulphide, and acetylacetone to cyclize into the systems, 1,2,4-triazolo, 2-methyltriazolo, triazolo-2-thione, and 1,2,4-triazepinopyrimido thienopyridocinnolines 6– 8, 11, respectively. Similarly, 3-amino-2-carboxamido-thienopyridocinnoline 12 was reacted with triethylorthoformate to give pyrimidothienopyridocinnoline-11-one 13, which was treated with phosphorous oxychloride and then hydrazine hydrate to produce 11-hydrazinopyrimido system 16. Treatment of 16 with triethylorthoformate, acetic anhydride, carbon disulphide, and ethyl chloroformate afforded the systems, 1,2,4-triazolopyrimidothienopyrido-cinnoline derivatives 16– 18, 20, respectively.

BASE CATALYSED LOSSEN REARRANGEMENT OF N-SULPHONYLOXY-2,3-NORBORN-5-ENEDICARBOXIMIDE

Abstract N-Sulphonyloxy-2,3-norborn-5-enedicarboximide 1 underwent Lossen rearrangement with some nucleophilic reagents, but it failed to undergo Beckmann rearrangement.