Crystalline form of magnesium salt of mono-p-nitrobenzyl malonate and process for producing the same.

摘要

The present invention provides a crystal modification of magnesium salt of mono-p-nitrobenzyl malonate (hereinunder referred to as " beta -type crystal") which is characterized by an X-ray diffraction pattern having strong peaks at angles of diffraction of (2 theta ) [ DEG ] 4.5, 8.9 and 13.3 according to X-ray diffractometry with Cu-K alpha line, and a process for producing the beta -type crystal modification of magnesium salt of mono-p-nitrobenzyl malonate comprising the step of reacting a water-soluble magnesium salt with an alkali metal salt or ammonium salt of mono-p-nitrobenzyl malonate. This process facilitates the production of the beta -type crystal modification having a higher purity than a known alpha -type crystal modification. The beta -type crystal is a very useful intermediate as a starting material of pharmaceutical.