Benzothiazole → 2-Acetylbenzothiazole

HRID 1178212Notes

Reaction equation

C([Li])CCC.[S:6]1[C:10]2[CH:11]=[CH:12][CH:13]=[CH:14][C:9]=2[N:8]=[CH:7]1.CON(C)[C:18](=[O:20])[CH3:19]>C1COCC1>[S:6]1[C:10]2[CH:11]=[CH:12][CH:13]=[CH:14][C:9]=2[N:8]=[C:7]1[C:18](=[O:20])[CH3:19]

Participants

Conditions

Temperature: -78 °C

Procedure

Butyllithium (10.2 mL, 16.3 mmol, 1.6 M, 1.1 Eq) was added dropwise to a stirred solution of benzothiazole (1.6 mL, 14.8 mmol, 1.0 Eq) in anhydrous THF (15 mL) at −78° C. under nitrogen. The resultant solution was stirred at −78° C. for one hour. N-Methoxy-N-methylacetamide (1.7 mL, 16.3 mmol, 1.1 Eq) was added in one portion and the reaction stirred at −78° C. for 3 hours. The resultant solution was allowed to warm to room temperature overnight. The reaction was quenched by the addition of 1M HCl (10 mL) and extracted with ethyl acetate (3×15 mL). The combined organic extracts were dried over solid MgSO4 and filtered. The filtrate was concentrated under reduced pressure and purified by column chromatography (10% ethyl acetate in hexanes) to give the title compound as a yellow solid (1.0 g, 39% yield): 1H NMR (400 Mhz, CDCl3) δ 2.85 (3H, s), 7.54-7.62 (2H, m), 8.01 (1H, d), 8.21 (1H, d); MS: ES+ 178.0 (100%).

Workup

temperatureto warm to room temperature overnight
customThe reaction was quenched by the addition of 1M HCl (10 mL)
extractionextracted with ethyl acetate (3×15 mL)
dry with materialThe combined organic extracts were dried over solid MgSO4
filtrationfiltered
concentrationThe filtrate was concentrated under reduced pressure
custompurified by column chromatography (10% ethyl acetate in hexanes)

Sources & evidence

ORD record: ord-af27dd1735af46a499cbf7db31edbb05
Source dataset: uspto-grants-2007_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07276502B2

Reaction notes

Loading…