299165-55-2Relevant academic research and scientific papers
Studies on the synthesis of some new cyanopyridine-thione and thieno[2,3-b]pyridine derivatives
Mohamed, Omima S.,Al-Taifi, Elham A.,El-Emary, Talaat I.,Bakhite, Etify Abdel-Ghafar
, p. 1061 - 1082 (2008/02/01)
The work included in this article involves the synthesis of new cyanopyridinethiones as good synthons for new thieno[2,3-b]pyridines with anticipated biological activities. Thus, the reaction of -aryl - thiocarbamoylacrylonitrile (1a-c) with (2-thenoyl)-,-trifluoroacetone led to an unexpected formation of 4-aryl-3-cyano-6-(2-thienyl)pyridine-2(1H)-thiones (4a-c). In contrast, the reaction of 1a,b with ethyl acetoacetate produced 4-aryl-3-cyano-5-ethoxycarbonyl-6-methylpyridine-2(1H)-thiones (12a,b). The reaction of compound 4a with methyl iodide gave 2-methylthio derivative 6, which upon treatment with hydrazine hydrate furnished pyrazolopyridine 7. Treatment of 4a-c with chloroacetaimde, in the presence of sodium ethoxide, led to the formation of 3-amino-4-aryl-6-(2-thienyl)thieno[2,3-b]pyridine-2-carboxamides (8a-c). The reactions of 8a with some aromatic aldehydes and/or cycloalkanones were carried out and their products were identified. Compounds 12a,b were reacted with chloro-N-arylacetamides to give ethyl 4-aryl-2-(N-aryl) carbamoylmethylthio-3-cyano-6-methylpyridine-5-carboxylates (13a-j). Upon treatment of compounds 13a-j with sodium alkoxide in alcohol, they underwent an intramolecular Thorpe-Ziegler cyclization to furnish ethyl 3-amino-4-aryl-2-(N- aryl)carbamoyl-6-methylthieno[2,3-b]pyridine-5-carboxylates (14a-j). Compounds 14a-j, in turn, were reacted with triethyl orthoformate and/or carbon disulfide to give corresponding pyridothienopyrimidinone derivatives 15a-j and 18. Pyridothienotriazinone analogs 17a-j were synthesized via diazotisation of compounds 14a-j.
Synthesis of some new pyridothienopyrimidines and related [1,2,4]triazolopyridothienopyrimidines
Bakhite, E.A.,Abdel-Rahman, A.E.,Mohamed, O.S.,Thabet, E.A.
, p. 236 - 247 (2007/10/03)
3-Amino-4-phenyl-6-(2-thienyl)thieno[2,3-b]pyridine-2-carboxamide (3a) reacted with triethyl orthoformate to give the pyrimidinone derivative 4. Reaction of 4 with phosphorus oxychloride produced the corresponding 4-chloropyrimidine derivative 5 which underwent some nucleophilic displacements upon treatment with thiourea, morpholine or aniline to give the pyridothienopyrimidine derivatives 6, 8 and 9 respectively. Similarly, the reaction of 5 with hydrazine hydrate afforded 4-hydrazino-9-phenyl-7-(2-thienyl)pyrido[3',2':4,5]thieno[3,2-d]pyrimidine (10). The condensation of 3-amino-4-phenyl-6-(2-thienyl)thieno[2,3-b]pyridine-2-carbonitrile (3b) with triethyl orthoformate led to the methanimidate derivative 18 which upon treatment with hydrazine hydrate furnished 3-amino-3,4-dihydro-4-imino-9-phenyl-7-(2-thienyl)pyrido[3',2':4,5]thieno[3,2-d]pyrimidine (19). The compounds 10 and 19 were used as precursors for synthesizing the isomeric [1,2,4]triazolopyridothienopyrimidines via Dimroth rearrangements.
Some reactions of 2-functionalized 3-amino-4-aryl-6-(2′-thienyl)-thieno[2,3-B]-pyridines: Synthesis of new pyridothienopyrimidines, pyridothienotriazines and related fused tetracyclic systems
Abdel-Rahman,Bakhite,Mohamed,Thabet
, p. 89 - 106 (2007/10/03)
4-Aryl-3-cyano-6-(2′-thienyl)-pyridine-2(1H)-thiones (2a-c) were prepared and reacted with chloroacetonitrile or chloroacetamide to furnish 3-amino-4-aryl-6-(2′-thienyl)-thieno[2,3-b]pyridine-2-carbonitriles (4a-c) and 2-carboxamide analogs 6a-c respectiv
