N-CARBONIC ANHYDRIDE OF GLUTAMIC ACID BENZYL ETHER Russian patent published in 2015 - IPC C07D263/44 

FIELD: chemistry.

SUBSTANCE: invention relates to a method of crystallising N-carbonic anhydride of glutamic acid benzyl ether. The disclosed method includes dissolving N-carbonic anhydride of glutamic acid benzyl ether in a solvent heated to a temperature of 40°C or higher but lower than the boiling point thereof, and the amount of which is 0.5 l or more per mole of N-carbonic anhydride of glutamic acid benzyl ether. A weak solvent is then added in amount of 1.4 l or more per mole of N-carbonic anhydride of glutamic acid benzyl ether at a temperature equal to higher than 40°C, but lower than the boiling point thereof. Further, crystals are precipitated at a temperature equal to higher than 40°C, but lower than the boiling point, and the crystals are cooled to obtain crystalline polymorphs of N-carbonic anhydride of glutamic acid benzyl ether. The solvent which is heated to a temperature of 40°C or higher, but below the boiling point, is ethyl acetate and the weak solvent is an aliphatic hydrocarbon. The invention also relates to crystalline polymorphs of N-carbonic anhydride of glutamic acid benzyl ether obtained using said method.

EFFECT: present method enables to obtain crystalline polymorphs of N-carbonic anhydride of glutamic acid benzyl ether, having high bulk density and excellent storage stability.

5 cl, 5 dwg, 1 tbl, 3 ex