3- Aminothiophene-2-carboxylate, methyl

Table 6. Physical, Toxicological, and Ecotoxicological Properties of Methyl 3-Aminothiophene-2-Carboxylate and Methyl 3-Amino-4-Methylthiophene-2-Carboxylate...

Property Methyl 3-aminothiophene-2-carboxylate Methyl 3-amino-4-methvlthiophene-2-carboxvlate... 

Agrochemical Products. The principal thiophene derivative in herbicidal protection, one of a range of sulfonylurea herbicides, is Harmony [79277-27-3] (Du Pont) (60), based on the intermediate methyl 3-aminothiophene-2-carboxylate (9). The product is characterized by a rapid biodegradabHity in the soil. Many other thiophene derivatives have been shown to have agrochemical activity, but few of these have been developed to the commercial level. 

Aminothiophene, readily available from methyl 3-aminothiophene-2-carboxylate, undergoes a condensation reaction with compound 92, followed by heating at elevated temperatures in Dowtherm , to produce pyridone product (Equation 28). The pyridone can be converted into a thieno[3,2- ]pyridine derivative in a few straightforward steps <2004BML21>. 

A one-pot procedure was developed (2001JHC419) for the synthesis of (2-al-kylthio-4-oxothieno[3,2-[Pg.87]

The Balz-Schiemann reaction, the classic synthesis of fluoro-aromatic compounds, involves diazotisation of an aromatic amine, isolation of the diazonium fluoroborate or hexafluorophosphate, then thermal decomposition of the dry salt, usually diluted with sand for safety. It is a useful method, with application to a number of heterocyclic systems, for example methyl 3-aminothiophene-2-carboxylate. ... 

The reaction of (148) with glycol and hydrogen peroxide gave (149). Compound (19b) has been reduced with liAlH4 to the corresponding alcohol, which was converted into the aldehyde and bromomethyl and aminomethyl derivatives that are of pharmaceutical interest. A mild method for the hydrolysis and decarboxylation of various amides of methyl 3-aminothiophen-2-carboxylates has been developed. Thermal decomposition of (150) led to cleavage of the thiophen ring, with extrusion of sulphur and formation of the isothiazole (151). ... 

Methyl 3-aminothiophene-2-carboxylate can be easily transformed into the IV,A-dimethyl or N,N-diethyl (but not A,A-diisopropyl) amide by treatment with 2 equiv. of the corresponding lithium amide. The reaction conditions are mild, and the yields are good <92TL6453). Trifluoroacetamides of aminothiophene and aminobenzo[i]thiophene have been prepared by Curtins rearrangement of the corresponding acylazides (toluene or benzene) and treatment of the resultant isocyanates with CFJCO2H at room temperature <92H(34)149>. 

Multiple labelling with both stable and radioactive isotopes offers the advantage of simultaneous labelling in the same position of a molecule [68]. The combination of C- and C-labelling combines ease of detection with rapid structural identification. The adoption of this technique in studies of some aspects of the metabolism of 4-morpholino-2-piperazinothieno [3,2-d] pyrimidine (V-K 774) (3) in the rat has been reported [69]. Potassium [ C, C]thiocyanate was prepared from a mixture of potassium [ C, C]cyanides. Reaction with ethyl bromide and methyl 3-aminothiophen-2-carboxylate (4) afforded the thienopyri-midine (5), which, by a series of reactions was converted to V-K 774 (3) labelled in the position shown. 

An elegant method for the utility of unstable 3-unsubsti-tuted 2-aminothiophene derivatives 385 in the Yonemitsu-type reaction has been elaborated by Krayushkin et al. (Scheme 13.81) [153]. Starting from stable 4,5-disubstituted ethyl 2-aminothiophene-3-carboxylates 383, the ester functionality is hydrolyzed to yield the corresponding alkali metal carboxylates 384. These are directly subjected to the three-component Yonemitsu-type reaction in acetic acid as the reaction medium. Protonation of the carboxylate followed by decarboxylation generates the 2-aminothiophene derivatives 385 that directly undergo Yonemitsu reaction without the need of isolation of those intermediates. This method has been applied to methyl 2,4-diaminothiazole-5-carboxylates 388 [154], ethyl 5-aminopyrazole -carboxylates 389 [155], dimethyl 3-aminopyrrol-2,4-dicarboxylates 390 [156], 4,5-disubstituted methyl 3-aminothiophene-2-carboxylates 391 [157], dimethyl 3-amino-4-phenylthiophene-2,5-dicarboxylate 392 [156], and ethyl 5-amin(Mmidazol-4-carboxylates 393 [158]. 

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