ChemicalBook CAS DataBase List 5-ETHYL-THIOPHENE-2-CARBOXYLIC ACID

5-ETHYL-THIOPHENE-2-CARBOXYLIC ACID synthesis

10synthesis methods

Product Name:5-ETHYL-THIOPHENE-2-CARBOXYLIC ACID
CAS Number:23229-72-3
Molecular formula:C7H8O2S
Molecular Weight:156.2

872-55-9
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$22.00/5g

23229-72-3
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$45.00/50mg

Yield: 99%

Reaction Conditions:

with n-butyllithium in tetrahydrofuran;hexane

Steps:

3.a 3a.
3a. 5-Ethyl-2-thiophenecarboxylic acid To a solution of 20 g (0.18 mol) of 2-ethylthiophene (Aldrich Chemical Co.) in 150 mL of THF cooled to 0° C. was added 73 mL (0.18 mol) of 2.5M (in hexane) n-butyl lithium, and the solution was stirred at 0° C. for 40 min, then cooled to -15° C., and gaseous CO₂ was bubbled into the mixture. After 40 min, the solution was poured into water and adjusted to pH 14 by addition of 20% NaOH. The solution was washed with ether, which was discarded, and the aqueous layer was adjusted to pH 1 with 6N HCl. This solution was extracted 3* with ethyl acetate, and the extract was dried over MgSO₄ and concentrated to give 28.3 g (99% yield) of the title product. MS 174 (M+H)⁺. NMR (CDCl₃) δ:7.73 (d, 1H, J=3 Hz), 6.84 (d, 1H, J=3 Hz), 2.90 (q, 2H, J=7 Hz), 1.35 (d, 3H, J=7 Hz).

References:

Abbott Laboratories US5597832, 1997, A

527-72-0 Synthesis