Heterocyclen aus CH‐aciden Nitrilen, VIII. 2‐Amino‐thiophene aus methylenaktiven Nitrilen, Carbonylverbindungen und Schwefel

Gewald, K.; Schinke, Elfriede; Böttcher, H.

doi:10.1002/cber.19660990116

Cited by 795 publications

(358 citation statements)

References 12 publications

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“…The most convergent and well established classical approach for the preparation of 2-aminothiophenes is Gewald's method [2,3], which involves the multicomponent condensation of aketone with an activated nitrile and elemental sulfur in the presence of diethylamine as acatalyst. The crystal structure of 5-acetyl has been reported [4].…”

Section: Discussionmentioning

confidence: 99%

Crystal structure of diethyl 2-amino-4-methylthiophene-3,5- dicarboxylate, C11H15NO4S

Zhang¹,

Jiao²

2010

Zeitschrift Für Kristallographie - New Crystal Structures

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Section: Discussionmentioning

confidence: 99%

Crystal structure of diethyl 2-amino-4-methylthiophene-3,5- dicarboxylate, C11H15NO4S

Zhang¹,

Jiao²

2010

Zeitschrift Für Kristallographie - New Crystal Structures

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“…The regioselectivity of the ring closure reactions was evident from NOESY and HMBC experiments. In summary, we have shown that fully protected ribofuranosylpropanal (1), 2-deoxyribofuranosylpropanal (14) and the corresponding alkynyl ketones 19, 20, 29, and 30 are suitable intermediates for the preparation of homo-and spacered C-nucleosides. The tetrahydrofuran ring and the protecting group pattern is stable enough even under drastic reaction conditions to allow the synthesis of a broad variety of heterocyclic systems.…”

Section: Synthesis Of Triazolo-and Pyrimidinobenzimidazole-spacered Cmentioning

confidence: 97%

“…alcohols, amines, aldehydes, and acetylenic ketones. 12 In this contribution we present our results on transformation of the furnished aldehydes (1,14) and acetylenic ketones (19,20, 29, 30) as versatile intermediates into a selected number of different heterocycles to make the synthetic potential of these precursors visible.…”

Section: Introductionmentioning

confidence: 99%

A versatile approach to novel homo-C-nucleosides based on aldehydes and acetylenic ketones derived from ribo- and 2-deoxy-ribofuranose C-glycosides

Waechtler¹,

Fuentes²,

Suárez³

et al. 2012

Arkivoc

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A series of ribofuranosyl-and 2-deoxyribofuranosyl homo-and spacered-C-nucleosides have been synthesized by reaction of fully protected 3-(1-deoxy-β-D-ribofuranosyl-1-yl)propanal (1), 3-(1,2-dideoxy-β-D-ribofuranos-1-yl)propanal (14), 1-(1-desoxy-β-D-ribofuranos-1-yl)pent-4-yn-3-on (19), 1-(1-desoxy-β-D-ribofuranos-1-yl)-5-phenyl-pent-4-yn-3-on (20), 1-(1,2-didesoxy-β-D-ribofuranos-1-yl)pent-4-yn-3-on (29), and 1-(1,2-didesoxy-β-D-ribofuranos-1-yl)-5-phenylpent-4-yn-3-on (30) with different nucleophiles. The preparation of 1 and 14 proceeds by Knoevenagel reaction with malononitrile, cyanoacetamide and 2-cyano-N-(4-methoxyphenyl)acetamide and subsequent cyclization with sulphur to thiophenes 5, 7, 8, 16 and then by cyclization with triethyl orthoformate to give thienopyrimidine 6 and thienopyrimidinone 9, 10, and 17. Treatment of acetylenic ketones 19, 20, 29, and 30 with acetamidinium chloride, benzamidinium chloride, and S-methylisothiouronium sulphate provided the corresponding pyrimidines 21-26, 31, 32. Finally, the use of 4H-1,2,4-triazol-3-amine and 2-aminobenzimidazole as 1,3-N,N'-dinucleophiles afforded the triazolopyrimidines 35, 39 and the pyrimidobenzimidazoles 36, 37, and 40, respectively. Deprotection of a selected number of Cnucleosides was achieved by one or two steps procedure without serious problems. That makes these C-nucleosides promising candidates for the synthesis of monomers suitable for solid phase nucleic acid oligomerization.

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“…The biological evaluation of the products was carried out at the Micro Analytical Center in Cairo University, Cairo, Egypt. Compounds 1 [18][19][20][21][22] and 2a [23] were prepared according to known methods (Scheme 1).…”

Section: Instrumentationmentioning

confidence: 99%

“…The diazo coupling reaction of the starting ethyl 2-amino-4-phenylthiophene-3-carboxylate (1) [18][19][20][21][22] with diazotized aromatic and heterocyclic amines resulted in the formation of the corresponding 5-aryl-and 5-heteroarylazo derivatives 2a-d (Scheme 1). Hydrazinolysis of 4-methoxyphenylazo derivative 2b in ethanol provided the target aminocarbohydrazide 3, whose structure was confirmed by examining spectroscopic data and elemental analysis.…”

Section: Chemistrymentioning

confidence: 99%

Regioselective synthesis and biological evaluation of some novel thiophene-containing heterocyclic scaffolds as potential chemotherapeutic agents

Gaber

Bagley

2011

Eur. J. Chem.

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KEYWORDSIn the reaction of 2-amino-3-carbethoxythiophene derivative 2b with hydrazine hydrate the respective aminocarbohydrazide 3 was isolated. Treatment of the latter product with carbon disulfide in alkaline medium caused a heterocyclization to give 1,3,4-oxadiazole-2-thione 5 rather than 3-amino-2-thioxothieno[2,3-d]pyrimidin-4-one 4, which could be obtained on treatment of carbohydrazide 3 with thiourea. The structure of products 4 and 5 was proved by spectroscopic methods and chemical transformations. Derivatization led to two novel series of condensed and uncondensed thiophenes, which were of significant interest for biological study. Since compound 4 contains two adjacent reactive functional groups, it reacted readily with different electrophilic reagents to provide a series of thieno[2,3-d]pyrimidin-4-one derivatives with annelated bridgehead nitrogen heterocycles 8-11, whereas a second series of 3-heteroaryl-substituted thiophenes 13-17 was obtained by thioamide functionalization in 1,3,4-oxadiazole derivative 5 using various chemical reagents. The new thiophene-based derivatives were evaluated for their preliminary antimicrobial activity against a representative panel of Gram-positive and Gram-negative bacteria as well as fungi strains. The compounds tested displayed different levels of inhibitory effects, with the assays carried out on two pathogenic bacteria and two pathogenic fungi. Of these compounds, the monocyclic aminothiophene derivative 15 showed the highest effect on pathogenic bacteria, while the tricyclic condensed thiophene derivative 8 was observed to have the same inhibitory effect against pathogenic mould (Aspergillus flavus) as the reference drug Amphotericin B. For those derivatives belonging to first series of condensed thiophenes with annelated bridgehead nitrogen heterocycles, it has been observed that the antibacterial effect was in general found to be significantly higher than the corresponding uncondensed analogues. Although most of the condensed and uncondensed thiophenes under investigation showed generally remarkable in vitro antibacterial activity, unfortunately, no significant antifungal activity was observed with any of the compounds tested except for 8. Surprisingly, compound 8 displayed an excellent effect on fungus (A. flavus) on the one hand, whereas the lowest effect on bacteria on the other. The attachment of a triazolothiadiazine moiety to a thiophene ring could be considered as a promising strategy for the development of new therapeutic antibacterial agents related to the aminothiophene system. Thienopyrimidinone Cyclocondensation Cyclodesulfurization Hydrazinolysis Alkylation Antimicrobial activity

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Heterocyclen aus CH‐aciden Nitrilen, VIII. 2‐Amino‐thiophene aus methylenaktiven Nitrilen, Carbonylverbindungen und Schwefel

Cited by 795 publications

References 12 publications

Crystal structure of diethyl 2-amino-4-methylthiophene-3,5- dicarboxylate, C11H15NO4S

Crystal structure of diethyl 2-amino-4-methylthiophene-3,5- dicarboxylate, C11H15NO4S

A versatile approach to novel homo-C-nucleosides based on aldehydes and acetylenic ketones derived from ribo- and 2-deoxy-ribofuranose C-glycosides

Regioselective synthesis and biological evaluation of some novel thiophene-containing heterocyclic scaffolds as potential chemotherapeutic agents

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