(E)-N-Monoalkyl-3-oxo-3-(2-thienyl)propenamine and process for producing the same and (E,Z)-N-monoalkyl-3-oxo-3-(2-thienyl)propenamine and process for producing the same

The present invention provides a process for producing (E)-N-monoalkyl-3-oxo-3-(2-thienyl)propenamine represented by Formula (1); wherein R is a C 1-4 alkyl, the method comprising the steps of: maintaining a solution containing (Z)-N-monoalkyl-3-oxo-3-(2-thienyl)propenamine dissolved therein at 25°C or below to deposit crystals and separating crystals having a particle diameter of 100 µm or less from the deposited crystals; and a process for producing (E,Z)-N-monoalkyl-3-oxo-3-(2-thienyl)propenamine comprising the steps of: reacting an alkali metal salt of ²-oxo-²-(2-thienyl)propanal with a monoalkylamine compound; adding a water-insoluble organic solvent to the resulting reaction mixture; adding seed crystals containing (E)-N-monoalkyl-3-oxo-3-(2-thienyl)propenamine to an organic layer obtained by conducting separation; and keeping the resulting mixture at 25°C or below.