Sumika Fine Chemicals, Co.,ltd.

Sumitomo Chemical Company, Limited

Yoshiyuki Imamiya

Eiichi Iishi

Michio Matsuda

Chiharu Maeda

Hiroki Ueno

Yutaka Otani

Low-hygroscopic anhydrous mirtazapine crystals having a hygroscopic degree of not more than 0.6% by weight when the crystals are stored in the air having a relative humidity of 75% at 25&#xb0; C. under atmospheric pressure for 500 hours; a process for preparing anhydrous mirtazapine crystals having a hygroscopic degree of not more than 0.6% by weight when the crystals are stored in the air having a relative humidity of 75% at 25&#xb0; C. under atmospheric pressure for 500 hours, comprising drying crystals of mirtazapine hydrate; a crystal of a mirtazapine hydrate represented by the formula (I): wherein n is an integer of 1 to 5; and a process for preparing crystals of a mirtazapine hydrate, comprising crystallizing a crude mirtazapine using a water-soluble organic solvent and water. The anhydrous mirtazapine crystals can be suitably used, for instance, as an antidepressant.

Anhydrous mirtazapine crystals and process for preparing the same

Process for preparing piperazine derivatives

A method for producing alkylated cyanoacetylurea from an easily obtainable starting material. An industrially available cyanoacetylurea and a carbonyl compound are reacted in a polar solvent under reducing conditions to alkylate cyanoacetylurea In addition, a reaction of cyanoacetylurea and acetone under reducing conditions affords isopropylation of cyanoacetylurea.

Production method of alkylated cyanoacetylurea

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Osaka, Japan

Yoshiyuki Imamiya