Chlorosuccinimide → 2-n-butyl-6-chloro-3-n-propyl-3H-thieno[2,3-d]pyrimidine-4-one

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Reaction Conditions

Reaction Steps

In a sulfonation flask, 2.0 g (8 mmol) of 2-n-butyl-3-propyl-3H-thieno[2.3-d]pyrimidin-4-one are added, with stirring, to 15 ml of absolute pyridine. The internal temperature is then raised to 80° C. and then 1.87 g (14 mmol) of N-chlorosuccinimide (NCS) are added in smallish portions. After stirring for 3 hours at 90° C. 1.0 g of NCS is added and the mixture is stirred another 3 hours at 90° C. The pyridine is removed in a water-jet vacuum and the crude product so obtained is purified by column chromatography over silica gel (eluant:n-hexane/tert.butylmethylether=3:1), giving 0.9 g of 2-n-butyl-6-chloro-3-propyl-3H-thieno-[2.3-d]pyrimidin-4-one in the form of a beige powder having a melting point of 67-69° C.

Provenance & Evidence