反応 #81854

反応方程式

2-hydroxybenzenecarbothioamide

2-Hydroxybenzenecarbothioamide

ethyl 4-chloroacetoacetate

NaHCO3

CO2

NaHCO3

→

4a

収率 93.0%

2-(2-Hydroxyphenyl)-4-thiazoleacetic Acid Ethyl Ester

収率 93.0%

溶媒

EtOAc

THF

反応条件

後処理

1. 1
   温度to reflux under nitrogen for 2.5 days
2. 2
   その他The organic layer was separated
3. 3
   洗浄washed with brine (40 mL×2)
4. 4
   乾燥dried over MgSO4
5. 5
   ろ過filtered
6. 6
   濃縮After concentration in vacuo
7. 7
   その他the oily residue was chromatographed on silica gel gradient EtOAc/CH2Cl2

実験手順

A stirred solution of 2-hydroxybenzenecarbothioamide 3a (5.36 g, 35.0 mmol), ethyl 4-chloroacetoacetate (6.34 g, 38.5 mmol) in dry THF (70 mL) was heated to reflux under nitrogen for 2.5 days. At ambient temperature, the mixture was diluted with EtOAc (200 mL), then cautiously treated with saturated aq. NaHCO3 (40 mL), and followed by adding solid NaHCO3 in small portions until CO2 evolution ceased. The organic layer was separated, washed with brine (40 mL×2), dried over MgSO4, and filtered. After concentration in vacuo, the oily residue was chromatographed on silica gel gradient EtOAc/CH2Cl2 :0-4%) to provide 4a (8.53 g, 93%) as a white solid, which was recrystallized from toluene/hexane at -30° C. mp 35.5-36.5° C.; IR (neat) 3120, 1740, 480, 1225 cm-1 ; 1H NMR (DMSO-d6) δ1.15 (3H, t, J=7.1 Hz, CH3), 3.84 (2H, t, CH2), 4.07 (2H, q, J=7.1 Hz, CH2), 6.89 (1H, S, J=7.8 Hz, Ar), 6.97 (1H, d, J=7.8 Hz, Ar), 7.26 (1H, t, J=7.8 Hz, Ar), 7.48 (1H, s, 7.93 (1H, d, J=7.8 Hz, Ar, 11.29 (1H, s, OH); FABMS m/z 263 (M30 ), 264 (M+ +1); Anal. Calcd for C13H13NO3S: C, 59.30; H, 4.98; N, 5.32. Found: C, 59.16; H, 4.97; N, 5.50.

出典