1,1-Dimethylhydrazine → 7-chloro-N',N'-dimethylthieno[3,2-b]pyridine-2-carbohydrazide

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Reaction Steps

To a suspension of 7-chlorothieno[3,2-b]pyridine-2-carbonyl chloride 20 (1 g, 4.33 mmol) (scheme 6) in DCM (22 mL), 1,1-dimethylhydrazine (0.33 mL, 4.33 mmol) was added in one portion and the mixture was stirred for 5 h. More 1,1-dimethylhydrazine (0.33 mL, 4.33 mmol) was added and the mixture was stirred overnight at room temperature. The crude was diluted with EtOAc, extracted with 1N HCl, the aqueous solution basified to pH˜11 by addition of 1N NaOH, extracted with EtOAc, the organic phase dried over anhydrous Na2SO4 and concentrated under reduced pressure affording 237 (798 mg, 3.13 mmol, 72%) as a crude mixture that was used in the next step without further purification. MS (m/z): (M+1) 255.9 (100%), 257.9 (39%).

Provenance & Evidence