16488-58-7

Upstream product

• 854625-81-3 5-iodo-3-methyl-thiophene-2-carboxylic acid 
• 616-44-4 3-Methylthiophene 

Downstream Products

• 1338815-16-9 3-tert-butyl-1-(4-methylthiophen-2-yl)-1H-pyrazol-5-amine 
• 1338814-66-6 N-(4-(4-(3-(3-tert-butyl-1-(4-methylthiophen-2-yl)-1H-pyrazol-5-yl)ureido)naphthalen-1-yloxy)pyridin-2-yl)-2-methoxyacetamide 

Relevant academic research and scientific papers

USE OF 4-BROMO-3-METHYL-5-PROPOXYTHIOPHENE-2-CARBOXYLIC ACID 2,5-DIOXO-PYRROLIDIN-1-YL ESTER FOR PREPARING THE TRYPTASE INHIBITOR [4-(5-AMINOMETHYL-2-FLUORO-PHENYL)-PIPERIDIN-1-YL]-(4-BROMO-3-METHYL-5-PROPOXY-THIOPHEN-2-YL)-METHANONE

This invention is directed to a five step regio-specific synthesis of 4-bromo-3-methyl-5-propoxy-thiophene-2-carboxylic acid compound of formula 16 comprising the steps of acetalating 3-methyl-thiophene-2-carbaldehyde in an alcohol solvent; iodinating the acetalated 3-methyl-thiophene-2-carbaldehyde in an non-protic polar or hydrocarbon solvent to yield the corresponding iodinated and acetalated 3-methyl-thiophene-2-carbaldehyde product; treating the iodinated and acetalated product with water to yield the corresponding 5-iodo-3-methyl-thiophene-2-carbaldehyde; oxidizing the 5-iodo-3-methyl-thiophene-2-carbaldehyde to the corresponding 5-iodo-3-methyl-thiophene-2-carboxylic acid in ketone solvent; Ullmann coupling of the 5-iodo-3-methyl-thiophene-2-carboxylic acid with alkali metal propoxide salt using a copper catalyst in propanol to yield 3-methyl-5-propoxy-thiophene-2-carboxylic acid; esterifying 3-methyl-5-propoxy-thiophene-2-carboxylic acid to yield the corresponding alkyl 3-methyl-5-propoxy-thiophene-2-carboxylate; brominating the 3-methyl-5-propoxy-thiophene-2-carboxylic acid to yield the corresponding alkyl 4-bromo-3-methyl-5-propoxy-thiophene-2-carboxylate; and basic hydrolyzing the alkyl 4-bromo-3-methyl-5-propoxy-thiophene-2-carboxylate with base to yield 4-bromo-3-methyl-5-propoxy-thiophene-2-carboxylic acid.

4-BROMO-3-METHYL-5-PROPOXYTHIOPHENE-2-CARBOXYLIC ACID 2,5-DIOXO-PYRROLIDIN-1-YL ESTER, ITS REGIO-SPECIFIC SYNTHESIS AND INTERMEDIATE THERETO

The present invention is directed to 4-bromo-3-methyl-5-propoxythiophene-2-carboxylic acid 2,5-dioxo-pyrrolidin-1-yl ester, and intermediate, 3-methyl-5-propoxythiophene-2-carboxylic acid 2,5-dioxo-pyrrolidin-1-yl ester, thereto. The present invention is also directed to the regio-specific synthesis of 4-bromo-3-methyl-5-propoxythiophene-2-carboxylic acid 2,5-dioxo-pyrrolidin-1-yl ester compound comprising the steps of iodinating 3-methyl-thiophene with an iodinating agent in the presence of a strong base in an non-protic polar or hydrocarbon solvent to yield 2-iodo-4-methylthiophene; Ullmann coupling the 2-iodo-4-methylthiophene with an alkali metal propoxide salt using a copper catalyst in propanol to yield 4-methyl-2-propoxythiophene; coupling the 4-methyl-2-propoxythiophene with CO2 using strong base in an non-protic polar or hydrocarbon solvent to yield 3 methyl-5-propoxy-thiophene-2-carboxylic acid; esterifying the 3 methyl-5-propoxy-thiophene-2-carboxylic acid with N hydroxysuccinimide in the presence of a coupling agent in an non-protic polar, hydrocarbon or halohydrocarbon solvent to yield 3-methyl-5-propoxythiophene-2-carboxylic acid 2,5 dioxo-pyrrolidin-1-yl ester; and brominating the 3-methyl-5-propoxythiophene-2-carboxylic acid 2,5 dioxo-pyrrolidin-1-yl ester with a brominating agent in an inert solvent to yield 4-bromo-3-methyl-5-propoxythiophene-2-carboxylic acid 2,5-dioxo-pyrrolidin-1-yl ester.