Tetrahydrofuran → 2-Ethyl-4-methoxybenzothiazole-7-carboxylic acid
Reaction equation
Br[C:2]1[C:10]2[S:9][C:8]([CH2:11][CH3:12])=[N:7][C:6]=2[C:5]([O:13][CH3:14])=[CH:4][CH:3]=1.C1(P(C(P(C2C=CC=CC=2)C2C=CC=CC=2)(C)C)C2C=CC=CC=2)C=CC=CC=1.C(N(CC)CC)C.[C]=[O:52].[O:53]1[CH2:57]CCC1>O.C([O-])(=O)C.[Pd+2].C([O-])(=O)C>[CH2:11]([C:8]1[S:9][C:10]2[C:2]([C:57]([OH:53])=[O:52])=[CH:3][CH:4]=[C:5]([O:13][CH3:14])[C:6]=2[N:7]=1)[CH3:12]Participants
Reactant 5
Product 1
Reagents, catalysts & solvents 2
Conditions
- Temperature
- 90 °C
Procedure
A mixture of 7-bromo-2-ethyl-4-methoxybenzothiazole (2.96 g), palladium (II) acetate (240 mg), bis-diphenylphosphinopropane (900 mg), and triethylamine (15 ml) in tetrahydrofuran (150 ml) and water (20 ml) was charged with 150 psi of carbon monoxide and stirred at 90° C. for 3 days. The organic solvent was removed in vacuo and the residue partitioned between ethyl acetate (50 ml) and aqueous sodium hydroxide (1M, 2×50 ml). The aqueous extracts were combined, acidified to pH 4 with glacial acetic acid, extracted with ethyl acetate (3×50 ml). The organic extracts were combined, dried over magnesium sulphate (5 g), filtered, and the filtrate evaporated in vacuo Recrystallisation from ethyl acetate/hexane gave the desired product as an off-white solid (2.2 g). TLC Rf 0.30 (50%ethyl acetate in hexane)
Workup
- customThe organic solvent was removed in vacuo
- customthe residue partitioned between ethyl acetate (50 ml) and aqueous sodium hydroxide (1M, 2×50 ml)
- extractionextracted with ethyl acetate (3×50 ml)
- dry with materialdried over magnesium sulphate (5 g)
- filtrationfiltered
- customthe filtrate evaporated in vacuo Recrystallisation from ethyl acetate/hexane
Sources & evidence
- ORD record
- ord-5b9ada6ba8c84742b72d00d1c6664c56
- Source dataset
- uspto-grants-2001_11
- Patent number
- US06313116B1
Reaction notes
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