ChemInform Abstract: 2-(3-Acylselenoureido)benzonitriles and 2-(3-Acylselenoureido)thiophene-3-carbonitriles. Preparation, Structure Elucidation, Cyclization and Retrocyclization Reactions (original) (raw)
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Collection of Czechoslovak Chemical Communications, 1999
Synthesis of 2-(3-acylselenoureido)benzonitriles and 2-(3-acylselenoureido)thiophene-3-carbonitriles 5a-5f by addition of 2-aminonitriles 4a-4c to benzoyl-or 2,2-dimethylpropanoylisoselenocyanate and their cycloaddition reactions are described. Structures of compounds 5a-5f were supported by CIMS, FTIR, 1 H, 13 C, 77 Se and 15 N NMR spectra. The parameters of 15 N and 77 Se nuclei were obtained from inverse 1 H-X 2D HMBC and GSQMBC correlation experiments at natural abundance. Structure of compound 5b was confirmed by X-ray analysis. The geometry of 5b was optimized by ab initio RHF/DZVP quantum chemistry calculation. A very good correlation between the calculation and experimental data was found. The geometry of 5e was optimized by ab initio DFT/VWN/DZVP quantum chemistry calculation. It was found that title compounds 5a-5f do not undergo isomerization to acylisoselenoureas, in contrast to analogous ester derivatives. Fused 6-imino-6H-1,3selenazinium salts (chlorides 6a-6f, hydrogensulfates 7a-7f and tetrafluoroborates 8a-8f) were prepared by an acid cyclization of 5a-5f. It was found that neutralization of 6a-6f, 7a-7f and 8a-8f led to their retrocyclization to 5a-5f. Selenoureas 5a-5f with equimolar amounts of methanolic potassium hydroxide afforded potassium salts 9a-9f. Only the salts 9b, 9c, 9e and 9f of the thiophene series were isolated. Their heating in methanol solution led to deacylation of isoselenoureas 10b and 10c. The in situ prepared compounds 9a and 9d cyclized and deacylated to 4-aminoquinazoline-2-selenole 11a under the same conditions. The compounds 5a-5f and 10a-10c cyclized to fused 4-aminopyrimidine-2-selenols 11a, 11b and 4-aminopyrimidine-2-selenone 12c by boiling in methanolic potassium hydroxide solution.
Collection of …, 1999
Synthesis of 2-(3-acylselenoureido)benzonitriles and 2-(3-acylselenoureido)thiophene-3-carbonitriles 5a-5f by addition of 2-aminonitriles 4a-4c to benzoyl-or 2,2-dimethylpropanoylisoselenocyanate and their cycloaddition reactions are described. Structures of compounds 5a-5f were supported by CIMS, FTIR, 1 H, 13 C, 77 Se and 15 N NMR spectra. The parameters of 15 N and 77 Se nuclei were obtained from inverse 1 H-X 2D HMBC and GSQMBC correlation experiments at natural abundance. Structure of compound 5b was confirmed by X-ray analysis. The geometry of 5b was optimized by ab initio RHF/DZVP quantum chemistry calculation. A very good correlation between the calculation and experimental data was found. The geometry of 5e was optimized by ab initio DFT/VWN/DZVP quantum chemistry calculation. It was found that title compounds 5a-5f do not undergo isomerization to acylisoselenoureas, in contrast to analogous ester derivatives. Fused 6-imino-6H-1,3selenazinium salts (chlorides 6a-6f, hydrogensulfates 7a-7f and tetrafluoroborates 8a-8f) were prepared by an acid cyclization of 5a-5f. It was found that neutralization of 6a-6f, 7a-7f and 8a-8f led to their retrocyclization to 5a-5f. Selenoureas 5a-5f with equimolar amounts of methanolic potassium hydroxide afforded potassium salts 9a-9f. Only the salts 9b, 9c, 9e and 9f of the thiophene series were isolated. Their heating in methanol solution led to deacylation of isoselenoureas 10b and 10c. The in situ prepared compounds 9a and 9d cyclized and deacylated to 4-aminoquinazoline-2-selenole 11a under the same conditions. The compounds 5a-5f and 10a-10c cyclized to fused 4-aminopyrimidine-2-selenols 11a, 11b and 4-aminopyrimidine-2-selenone 12c by boiling in methanolic potassium hydroxide solution.
Keywords: cyanoselenoacetamide, N-methylmorpholinium 1,4,5,6,7,8-hexahydroquinoline-2-selenolates, multicomponent cyclocondensation, Hantzsch synthesis.
Synthesis of novel 2-aminothieno[3,2- d]thiazoles and selenolo[3,2- d]thiazoles
Journal of Molecular Structure, 2011
In this work, we described the synthesis of 3-isothiocyanatoselenophenes starting from 3-aminoselenophenes (using thiophosgene). Those compounds were then converted to the corresponding thioureas in the presence of ammonium hydroxide. Cyclization in 2-aminoselenolo[3,2-d]thiazoles was achieved using DDQ. 2-Aminothieno[3,2-d]thiazoles were obtained from 3-isothiocyanatothiophenes using the same pathway.
In this work, we report the synthesis and characterization of new compounds derived from thieno [d]pyrimidines. The formation of isolated and fused thieno [d]pyrimidine derivatives was achieved via reacting 5-amino-(2-methyl)thieno [3,4-d]pyrimidin-4(3-H)-one (3) with some selected reagents. The starting compound (2) was prepared in a quantitative yield using a modified procedure by conversion of the cyano group in 1 to the amide via hydrolysis using concentrated H 2 SO 4 . Methylthieno [3,4-d]pyrimidin-5-yl (8, 9, and 18), 3-phenylthieno[3,4-e][1,2,4]triazolo[4,3-c]pyrimidines (11-15) and tetrazolo[1,5-c]thieno[3,4-e]pyrimidine (16) have been synthesized in excellent isolated yield. The interaction of N-acetyl derivative 19 with benzaldehyde and=or some nitroso compounds afforded the chalcones and Schiff's bases derivatives 20 and 26a and c respectively. The latter compounds were used as key intermediates in the synthesis of N-acetylpyrazol-3-yl (21a and 21b), 6-phenylpyrimidine-2-(one)thione (22a and b), pyrazolo-1-carbothioamide (25), and thiazolidinone and b-lactam derivatives 28a and 28c and 30a and 30c respectively. The structures of these compounds were established by elemental analysis, infrared (IR), mass spectrometry (MS), and NMR spectral analysis.
Photoisomerization of Ethyl 2–(3–Acylselenoureido) thiophene–3–carboxylates and Their Benzoanalogues
Molecules, 1997
Synthesis, isomerisation and structure elucidation of the title compounds 1-6 and its isomers 7-12 by FTIR, 1 H, 13 C, 15 N, 77 Se NMR spectroscopy is reported. Ethyl 2-(3-acylselenoureido)thiophene-3carboxylates and their benzoanalogues (where acyl is benzoyl and pivaloyl) were prepared by addition of ethyl 2-aminothiophene-3-carboxylates and ethyl 2-aminobenzoate on benzoyl-or pivaloylisoselenocyanate in acetone solution. An isomerization of 1-6 to the corresponding 3-acylisoselenoureas 7-12 was obtained. The isomerisation proceeds either by irradiation with light (340-400 nm) or in the case of benzoylderivatives 1, 3, 5 by treatment with acetic acid. On the other hand the acid action in the pivaloyl set inhibited this isomerisation and evoked the retroisomerisation reaction of 8, 10, 12 to 2, 4, 6. Thermal analyses showed that isomerisation can be initiated also by heating. These changes proceed in the solid phase as an exothermic process at an elevated temperature but always below the temperature of melting. The structure 2 was supported by X-ray analysis. Molecular design of 2 and 8 was modeled during application of ab initio quantum chemistry calculation.
Helvetica Chimica Acta, 2008
Treatment of 3-aryl-2-thioxo-1,3-thiazolidin-4-ones 1 with CN À and NCO À effected the ring cleavage providing [(cyanocarbonothioyl)amino]benzenes 4 and arylisothiocyanates 5, respectively. Similar treatment of 5-(2-aryl-2-oxoethyl) derivatives 2 afforded 2,4-bis(2-aryl-2-oxoethylidene)cyclobutane-1,3-diones 6 along with each of the preceding products. Treatment of the respective (E,Z)-5-(2-aryl-2oxoethylidene) analogues 3b and 3c with CN À gave 4b and 4c and 2-(arylcarbonyl)-2-methoxy-4oxopentanedinitriles 7b and 7c, in addition to 3,6-bis[2-(4-chlorophenyl)-1-methoxy-2-oxoethylidene]-1,4-dithiane-2,5-dione 8c, which has been generated from 3c. Reactions of 3c or 3d with NCO À provided 5c or 5d, together with 8c or 8d as pure isomers. In the formation of the MeO products 7 and 8, the solvent (MeOH) has participated. Structures of these products are based on microanalytical and spectroscopic data. Rationalizations for the above transformations are given.
2016
Recently, in our laboratory a novel series of 1-phenyl-3-(4thiocarbamido phenyl)prop-2-ene-1-one(IIIa-e) were synthesized by the interaction of 1-phenyl-3-(4chlorophenyl)prop-2-en-1-one with different thiourea in isopropanol medium. Justification and determination of structure of synthesized compounds were done on the basis of chemical characteristics, elemental analysis and spectral studies. Dipak T. Tayade 1* , Sanghapal S. Padhen 2 1*Department if Chemistry, Govt. Vidarbha Institute of Science & Humanities, Amravati-444 604(MS) India 2 Department of Chemistry, Rajarshee Shahu Science College, Chandur Rly Dist Amravati-444904 (MS) India. Submission: 30 June 2016 Accepted: 5 July 2016 Published: 25 July 2016 www.ijppr.humanjournals.com Citation: Dipak T. Tayade et al. Ijppr.Human, 2016; Vol. 6 (4): 322-327. 323 INTRODUCTION Chalcone is an exceedingly imperative compound and used as an intermediate for the synthesis of various oxygen, nitrogen and sulphur containing heterocycles and...
Environmentally benign conditions have been developed for the synthesis of 2-amino-4-(2-oxo-2H-chromen-3-yl)thiophene-3-carbonitriles (3) starting from 3-acetyl-2H-chromen-2-one (1) through the intermediacy of 2-(1-(2-oxo-2H-chromen-3-yl)ethylidene)malononitrile (2) using the Knoevenagel condensation followed by the Gewald reaction. Alternatively, 3 could also be prepared in a one pot method by treating equimolar amounts of 1, malononitrile, and elemental sulfur. The merits of this preparation are mild reaction conditions, easy work-up procedure, and good yields.