反応 #816437

反応方程式

HCl

Ethyl oxalate

N-butyl-1-(4-chlorophenyl)methanesulfonamide

Potassium tert-butoxide

→

title compound

収率 60.0%

2-Butyl-5-(4-chlorophenyl)-4-hydroxyisothiazol-3(2H)-one 1,1-dioxide

収率 60.0%

溶媒

THF

反応条件

後処理

1. 1
   温度The mixture was cooled in an ice-bath
2. 2
   温度It was then cooled in an ice-bath
3. 3
   その他evaporated
4. 4
   その他to remove THF
5. 5
   抽出It was then extracted with DCM (20 mL)
6. 6
   乾燥The extract was dried (MgSO4)
7. 7
   その他evaporated
8. 8
   洗浄Column chromatography (ISOLUTE SI, 20 g/70 mL) of the residue, eluting with heptane
9. 9
   その他EtOAc:heptane (20:80), gave fraction

実験手順

The reaction was done in two vials. In each vial: N-butyl-1-(4-chlorophenyl)methanesulfonamide (0.5 g, 1.91 mmol) was dissolved in THF (3 mL). Ethyl oxalate (0.335 g, 2.29 mmol) was added. The mixture was cooled in an ice-bath. Potassium tert-butoxide (0.28 g, 2.48 mmol)) was added under nitrogen atmosphere. The mixture was heated in a microwave reactor at 150° C. for 10 mins. It was then cooled in an ice-bath. HCl (10%, ca.1 mL) was added, pH˜1. The mixtures of the two vials were combined and evaporated to remove THF. It was then extracted with DCM (20 mL). The extract was dried (MgSO4) and evaporated. Column chromatography (ISOLUTE SI, 20 g/70 mL) of the residue, eluting with heptane, then EtOAc:heptane (20:80), gave fraction A (0.9 g, containing ca. 60% of the title compound) and fraction B (0.035 g, the title compound). 1H NMR (400 MHz, THF-d8): δ 7.92 (d, 2H), 7.50 (d, 2H), 3.68 (t, 2H), 1.82-1.76 (m, 2H), 1.49-1.39 (m, 2H), 0.97 (t, 3H). 13C NMR (100 MHz, THF-d8): 159.2, 146.7, 135.4, 129.8, 129.4, 125.6, 117.7, 39.8, 31.2, 20.6, 13.7. Mass Spectrum: M−H+ 314.

出典