Acetamide → tert-butyl 2-amino-4H,5H,6H,7H-[1,3]thiazolo[5,4-c]pyridine-5-carboxylate

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Reaction Steps

Dissolved 4-Oxo-piperidine-1-carboxylic acid tert-butyl ester (15.0 g, 75.28 mmol) in 75 mL of cyclohexane. To this was added pyrrolidine (6.70 mL, 79.00 mmol) and a catalytic amount of TsOH. The mixture was refluxed with a Dean-Stark trap until no water was collected (5 h). The mixture was filtered and concentrated to an oily brown residue. The residue was dissolved in 25 mL of anhydrous MeOH. To this mixture was added S(0) (2.40 g). The mixture was cooled in and ice bath and acetamide (3.19 g, 76.00 mmol) was added in portions. After 2 h and warming to room temperature a thick tan ppt. appeared. Filtered the material and washed with cold MeOH to give 10.04 g. A second ppt., 3.64 g, was collected. 1H NMR indicated identical material and these were combined to give 2-amino-6,7-dihydro-4H-thiazolo[5,4-c]pyridine-5-carboxylic acid tert-butyl ester.

Provenance & Evidence