Abu-Bakr A. A. M. El-Adasy

A Facile Synthesis of Some New Thiazolo[3, 2]pyridines Containing Pyrazolyl Moiety and Their Antimicrobial Activity

Abstract Condensation of 2-cyanomethyl-4-thiazolinone 1 with 1,3-diphenyl-pyrazole-4-carboxaldehyde 2 in ethanol containing a few drops of piperidine yielded the novel methylene derivative 3 . Compound 3 was refluxed with malononitrile to give the corresponding thiazolo[ [3] , [2] ]pyridine derivative 5 . Also, treatment of compound 3 with benzylidenemalononitriles gave the thiazolo[ [3] , [2] ]pyridine derivatives 6a–e . Refluxing of compound 6d with triethyl orthoformate furnished the ethoxymethylideneamino derivative 7 . Formic acid and malononitrile were reacted with compound 6d to produce thiazolo[ [3] , [2] ][ [1] , [8] ]naphthyridine derivative 8 and 11 , respectively. Condensation of 2 with cyanoacetohydrazide in ethanol containing piperidine as catalyst gave the hydrazone derivative 12 which, on treatment with salicyaldehyde and 2-cyano-3-(4-fluorophenyl)acrylic acid ethyl ester, yielded the novel chromene 13 and pyridinone 14 , respectively. Structures of the synthesized compounds have been established by elemental analysis and spectral data. Compounds 3 , 5 , 6a–d , 8 , 11 , 13 , and 14 have been screened for antimicrobial activities.

N-1-Naphthyl-3-oxobutanamide in Heterocyclic Synthesis: A Facile Synthesis of Nicotinamide, Thieno[2,3-b]pyridine, and Bi- or Tricyclic Annulated Pyridine Derivatives Containing Naphthyl Moiety

N-1-Naphthyl-3-oxobutanamide (1) reacts with arylidinecyanothioacetamide 2a–c in ethanol/piperidine solution under reflux to yield the pyridine-2(1H)-thiones 6a–c. Compound 6a reacts with α-haloketones 7a–e to give the 6-thio-N-1-naphthyl-nicotinamides derivatives 8a–e, which cyclized to thieno[2,3-b]pyridine derivatives 9a–e. The reaction of compound 9a with hydrazine hydrate and formamide gives the thieno[2,3-b]pyridine carbohydrazide derivative 10 and pyridothienopyrimidine derivative 11, respectively. Reaction of 9a with benzoyl isothiocyanate gave thiourea derivative 12. Compound 12, upon treatment with alcoholic NaOH, gave pyridothienopyrimidine 13. Saponifications of 9a gave the amino acid 15, which affords 16 when refluxed in Ac2O. Treatment of compound 16 with AcONH4/AcOH gave 17. Diazotization and self-coupling of 9b gave the pyridothienotriazine 18. Also, diazotization of the ortho-aminohydrazide 10 give the corresponding azide 19, which was subjected to Curtius rearrangement in boiling xylene to give imidazothienopyridine 20. Reaction of 10 with either formic acid or triethylorthoformate and phenyl isothiocyanate gave the corresponding pyridothienotriazepines 22 and 23, respectively. The interaction of 10 with acetylacetone furnished the pyrazolyl derivative 24. The structures of the synthesized compounds were established from their analytical and spectral data.

Synthesis and Antibacterial Activity of Some New Ethyl Thionicotinates, Thieno[2,3-b]pyridines, Pyrido[3′,2′:4,5] thieno[3,2-d]pyrimidines, and Pyrido[3′,2′:4,5]thieno[3,2-d][1,2,3]triazines Containing Sulfonamide Moieties

Ethyl 5-cyano-6-mercaptonicotinate derivatives 1a,b reacted with the N-[4-(aminosulfonyl) phenyl]-2-chloroacetamide derivatives 2a,b to give the ethyl 6-[(2-{[4-(aminosulfonyl) phenyl]amino}-2-oxoethyl)thio]nicotinate derivatives 3a–d. Cyclization of 3a–d afforded the corresponding ethyl 3-amino-2-({[4-(aminosulfonyl)phenyl]amino}carbonylthieno[2,3-b] pyridine-5-carboxylate derivatives 4a–d. Ethyl 3-[4-(amino-sulfonyl)phenyl]-4-oxopyrido [3′,2′:4,5]thieno[3,2-d]pyrimidine-8-carboxylate derivatives 5a–d and ethyl 3-[4-(amino- sulfonyl)phenyl]-4-oxopyrido[3′,2′:4,5]thieno[3,2-d][1,2,3]-triazine-8-carboxylate derivat- ives 6a–d were prepared from 4a–d. Reaction of 1a,b with chloroacetonitrile (7) and condensation of the thus formed 3-aminothienopyridines 8a,b with dimethylformamide-dimethylacetal (DMF-DMA) yielded the corresponding ethyl 2-cyano-3-{[(N, N-dimethylamino)methylene]amino}thieno[2,3-b]pyridine-5-carboxylate derivatives 9a,b. Reaction of compounds 9a,b with the sulfadiazine (10) gave ethyl 4-{[4-(amino- sulfonyl)phenyl]amino}pyrido[3′,2′:4,5]thieno[3,2-d]pyrimidine-8-carboxylate derivatives 12a,b. Antibacterial activity was screened for some of the newly synthesized compounds. Supplemental materials are available for this article. Go to the publishers online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

Some Nucleophilic Reactions with Isothiocyanatoazobenzene

The reactivity of Isothiocyanatoazobenzene 2 towards some nucleophiles was investigated. Thus, reaction of isothiocyanate 2 with aromatic amines gave thioureas 3a–d . The reaction of compound 3a with arylidenemalononitriles 4a,b afforded the corresponding 1,3-pyrimidines 7a , b . Thiosemicarbazide 8 and ethyl thiocarbamate 9 were synthesized by interaction of isothiocyanate 2 with hydrazine hydrate and ethanol, respectively. Cyclocondensation of isothiocyanate 2 with 2-aminophenol and anthranilic acid produced the novel benzoxazole 11 and quinazolinone 13 derivatives , respectively. Finally, treatment of isothiocyanatoazobenzene 2 with compounds 14 and 17 afforded the novel thioureas 15 and 18 derivatives, respectively. The structures of the synthesized compounds were established from their analytical and spectral data.