2-Amino thiophen

Gewald K, Schinke E, Bottcher H. 2-Amino-thiophene aus methylenaktiven Nitrilen, Carbonylverbindungen und Scwefel. Chem Ber 1966 99 94-100. 

Zum Ersatz des Jod-Atoms in Aryl-jodiden durch die unsubstituierte Amino-Gruppe eig-net sieh auch die Reaktion mit Kupfer(I)-bis-[trimethylsilyl]-amid in siedendem Pyridin das auf diese Weise zunachst erhaltene Aryl-bis-[trimethylsilyl]-amin ergibt bei der Methanolyse das primare aromatische Amin, z. B. Anilin (60%), 4-Methoxy- (45%), 4-Me-thyl-anilin (50%), 2-Amino-thiophen (45%). Das Kupfer(I)-bis-[trimethylsilyl]-amid wird in situ aus Hexamethyldisilazane, Butyllithium und Kupfer(I)-jodid erzeugt4. 

Trioxopyrido[3,2, 4,5]thieno[3,2-<7]pyrimidin-4(3//)-ones were synthesized by the reactions of 3-amino-2-ethoxycarbonylthieno[2,3-Z>]pyridines with isothiocyanates (1997JHC937) or by the reactions of 3-amino-2-cyano(carbamoyl)thieno[2,3-Z>]pyridines with carbon disulfide (1998M523). An analogous reaction of 2-amino-thiophene-3-carboxamide with carbon disulfide yielded thioxopyrimidinone 10 (1990PS181, 1993MI1). 

Microwave irradiation in the presence of triethylamine was used for the synthesis of 4,5-unsubstituted 2-amino-thiophenes using thioacetaldehyde dimer. ... 

Amino-3-cyano-thiophenes or 2-amino-thiophene-3-esters result from this route, generally conducted as a one-pot process, involving a ketone that has an a-methylene, ethyl cyanoacetate or malononitrile, sulfur, and morpholine. Various improvements to the original procedure include using microwave irradiation on solid snpport, or with potassium fluoride on alumina as the base, or solvent-free,and using morpho-lininm acetate in excess morpholine for aryl alkyl ketones. 

Thiourea has been used similarly to prepare, at 175°C (3 hr) up to 205°C (20 min), good yields of annelated 2-thioxopyrimidin-4-ones such as 8-methyl-2-thioxo-8-azapurin-6-one (156) from 4-amino-1,2,3-triazole-5-car-boxamides (see 20),254 as well as pyrazolo[4,3-d]- and pyrazolo[3,4-d]pyri-midinediones from the appropriate aminopyrazolecarboxamides (see 15) 24,221 and thieno[2,3-d]pyrimidine-2,4-diones (see 12) from 2-amino-thiophene-3-carboxamide.25 5... 

The preparation and formylation of 2-(acetamido)thiophens has been improved, and high yields have been obtained.Many derivatives of (6) have been prepared, among them bicyclic derivatives such as (95). 2-Amino-thiophens have been allowed to react with active-methylene derivatives in the presence of ethyl orthoformate, to give compounds such as (96). By allowing... 

The MCR covered herein has found broad applicability in the synthesis of heterocycles containing Gewald moiety (2-amino-thiophene) (Fig. 12.5), with interesting properties [138] and overall antimicrobial activities, such as phthala-zinediones [139], thienopyridines [140], thienothiadiazines... 

K. Gewald, E. Schinke, H. Bottcher, Chem. Ber. 1966, 99, 94-100. 2-Amino-thiophene aus methylenaktiven nitrilen carbonylverbindungen und schwefel. (Heterocycles from C-H acidic nitriles VIII. 2-Aminothiophenes from methylene active nitriles, carbonyl compounds, and sulfur). 

B. V. Lichitsky, A. N. Komogortsev, A. A. Dudinov, M. M. Krayushkin, Russ. Chem. Bull. 2008, 57, 2175-2179. Three-component condensation of 2-amino thiophene-3-carboxylic acid derivatives with aldehydes and Meldrum s acid. 

Scheme 72 shows a nice example of this modification using 1,3-dichIoroacetone, thus producing two 2-amino-thiophene units [118],... 

The reaction of 2,6-dioclyl-4,8-diethynyl-benzo[l,2-b 4,5-b ]dithiophene with dibromide compounds in toluene by Pd/Cu-catalyzed Sonogashira coupling copolymerization produced the polymers PEBBDT and PEBTTZ. Thiophene-3-carboxylic acid was similarity converted into the 2,6-Dioctyl-4,8-diethynyl-benzo [l,2-b 4,5-b ]dithiophene as the synthesis of common BDT compound [72]. EoUowing a three-component reaction, aldehyde, sulfur, and cyanoacetate of the 2-aIkyl substituted thiophene unit was converted into 2-amino thiophene [73]. The compound was obtained in good yield by the reaction of deamination and hydrolysis. PEBBDT was readily soluble in organic solvents like chloroform, THE, chlorobenzene (CB), etc. at room temperature but PEBTTZ was less soluble in these solvents [71]. 

Two papers dealing with HMO calculations of the chemical reactivity of substituted thiophens should be noted one on the acid-catalysed hydrogen exchange" and the other on the transmission of substituent effects across the thiophen ring" Gol dfarb et al." have studied another problem in chemical reactivity electrophilic substitution of thiophen-2-carbaldehyde occurs in the 5-position but at the 4-position when this compound is protonated, and substitution in protonated 2-amino-thiophens occurs at the 5-position despite the m-directing property of the ammonium group. They found the chemical reactivity to be related to the CNDO/2 valence-electron densities." ... 

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