摘要:
It is intended to provide a process for producing (E)-N-monoalkyl-3-oxo-3-(2-thienyl)propenamine represented by the general formula (I): (wherein R represents an alkyl group having 1 to 4 carbon atoms), characterized by maintaining a solution in which (Z)-N-monoalkyl-3-oxo-3-(2-thienyl)propenamine is dissolved in a solvent at 25°C or lower thereby to deposit crystals and fractionating a crystal with a particle size of 100 µm or less from the deposited crystals; and a process for producing (E,Z)-N-monoalkyl-3-oxo-3-(2-thienyl)propenamine, characterized by adding a water-insoluble organic solvent to a reaction solution obtained by reacting an alkali metal salt of β-oxo-β-(2-thienyl) propanal with a monoalkylamine compound, adding a seed crystal containing (E)-N-monoalkyl-3-oxo-3-(2-thienyl)propenamine to an organic layer obtained by separation and maintaining the temperature at 25°C or lower.