2-AMINO-5,5,7,7-TETRAMETHYL-4,5,6,7-TETRAHYDRO-THIENO[2,3-C]PYRIDINE-3-CARBOXYLIC ACID ETHYL ESTER synthesis
- Product Name:2-AMINO-5,5,7,7-TETRAMETHYL-4,5,6,7-TETRAHYDRO-THIENO[2,3-C]PYRIDINE-3-CARBOXYLIC ACID ETHYL ESTER
- CAS Number:133894-40-3
- Molecular formula:C14H22N2O2S
- Molecular Weight:282.4
826-36-8
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133894-40-3
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Yield:-
Reaction Conditions:
with sulfur;diethylamine in ethanol;Heating;
Steps:
Synthesis of the Ethyl 5,5,7,7-tetramethyl-2-(4-(triuoromethyl) benzamido)-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxylate (5A)
Briefly, the 2,2,6,6-tetramethylpiperidine ketone (1, 1 equivalent) was mixed with 2-cyanoacetateesters (2, 1 equivalent) and elemental sulfur (1 equivalent) in the presence of diethylamine(3 equivalents) in ethanol (ETOH) at 60 C for 17 h. The crude was precipitated by adding waterand filtered to provide the desired known 2-aminothiophene intermediate (3) [12]. The latterwas reacted with 4-triuomethy benzoyl chloride in the presence of diisopropylethylamine in drydichloromethane at 0 C for 1 h and then at room temperature for 4 h. The solvent was evaporatedthen the crude mixture was purified by flash-column chromatography on silica gel, using a mixtureof solvent of dichloromethane: methanol (DCM: MeOH) at ratios from 100:1 to 50:1, to providethe desired ethyl 5,5,7,7-tetramethyl-2-(4-(triuoromethyl)benzamido)-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxylate (5A) as a light brown solid. The purity of 5A was confirmed by 1H-NMR,13C-NMR, LC/MS and melting point.
References:
Rodriguez, Felipe;Iniguez, Eva;Contreras, Guadalupe Pena;Ahmed, Haidar;Costa, Thadeu E. M. M;Skouta, Rachid;Maldonado, Rosa A. [Molecules,2018,vol. 23,# 7,art. no. 1626]