Hydrochloric Acid → 3-Ethoxycarbonylmethyl-2-hydrazonothiazolidin-4-one

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Reaction Steps

To 2.0 g of 3-ethoxycarbonylmethyl-2-isopropylidenehydrazonothiazilidin-4-one obtained in step (1) of Example 9 was added 30 ml of 0.5N hydrochloric acid, and the mixture was subjected to steam distillation for 15 minutes. The reaction mixture obtained was cooled, the resulting precipitates were distilled off, and the filtrate was concentrated under reduced pressure. To the residue formed were added a saturated sodium hydrogencarbonate solution and chloroform to distribute the residue between them. The organic layer was washed three times with water, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue formed was charged on silica gel column chromatography and eluted with a mixture of chloroform and ethyl acetate at 4:1 by volume to obtain 870 mg of 3-ethoxycarbonylmethyl-2-hydrazonothiazolidin-4-one.

Provenance & Evidence