Tetrahydrofuran → 2-(4-Methoxyphenylpropionyl)amino-6-n-propylamino-4,5,-6,7-tetrahydrobenzothiazole

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Reaction Steps

15.1 g (0.09 mol) of 6-oxo-2-amino-tetrahydrobenzothiazole and 20.5 g (0.1-mol) of 4-methoxyphenylpropionyl chloride are refluxed for 2 hours in 450 ml of tetrahydrofuran and 0.1 mol of triethylamine, subsequently poured onto ice and extracted with ethyl acetate. After drying, 2-(4-methoxyphenylpropionyl)amino-6-oxo-tetrahydrobenzothiazole (17.5 g) crystallises out on concentrating, and, is dissolved in methanol and is reductively aminated, without further purification, in an autoclave using propylamine (Raney nickel, 5 bar, 60° C.). After filtering off the catalyst under suction, the solvent is removed by distillation. The residue crystallises from i-propyl ether. Yield: 12.5 g (63% of theory)

Provenance & Evidence