US 5,463,116 A · Crystals of N- (trans-4-isopropylcyclohexlycarbonyl)-D-phenylalanine and methods for preparing them

Abstract

Stable crystals of N-(trans-4-isopropylcyclohexylcarbonyl)-D-phenylalanine may be produced by treating this compound with a solvent at a temperature of at least 10.degree. C. and forming crystals in the solvent at a temperature of at least 10.degree. C. For example, crystals may be formed by crystallization out of solution, or may be formed from solid particles of the compound suspended in a solvent. Crystals formed in this way have different melting point, infra red spectrum and X-ray diffraction patterns from previously known forms of the compound and have enhanced processability, e.g., stability to grinding.

Claims19

Dependent claims

Crystals of N-(trans-4-isopropylcyclohexylcarbonyl)-D-phenylalanine having at least one of the following properties:

(a) a melting point in the range of 136.degree.-142.degree. C.
(b) a powder X-ray diffraction pattern with reflection maxima at 2.theta. of about 8.1.degree., 13.1.degree., 19.6.degree. and 19.9.degree.;
(c) an infra red absorption spectrum with absorption bands in the region of 1714, 1649, 1542 and 1214 cm.sup.-1.

A method for the production of crystals of N-(trans-4-isopropylcyclohexylcarbonyl)-D-phenylalanine having at least one the following properties:

(a) a melting point in the range of 136.degree.-142.degree. C.;
(b) a powder X-ray diffraction pattern with reflection maxima at 2.theta. of about 8.1.degree., 13.1.degree., 19.6.degree. and 19.9.degree.;
(c) an infra red absorption spectrum with absorption bands in the region of 1714, 1649, 1542 and 1214 cm.sup.-1, comprising dissolving or suspending an N-(trans-4-isopropylcyclohexylcarbonyl)-D-phenylalanine not possessing any of said properties in a solvent in which it is completely or incompletely soluble at a temperature of at least 15.degree. C. and up to the boiling point of the solvent and permitting said crystals to crystallize from or form in said solvent at a temperature of 15.degree. C. of in excess thereof.

Dependencies are inferred from the claim text.

Crystals of N- (trans-4-isopropylcyclohexlycarbonyl)-D-phenylalanine and methods for preparing them

Life of this patent

Crystals of N- (trans-4-isopropylcyclohexlycarbonyl)-D-phenylalanine and methods for preparing them

Life of this patent

Abstract

Claims19