A novel crystalline form of quinapril hydrochloride of formula (I)
An amorphous form of quinapril hydrochloride substantially free of impurities, specially diketopiperazine compound, and conforming to pharmacopoeial specifications formed from the said novel crystalline form of quinapril hydrochloride of formula (I). The crystalline quinapril hydrochloride is in the form nitroalkane solvate in which the nitroalkane is nitromethane, nitroethane and nitropropane. Each such nitroalkane solvate having particular characteristic X-ray diffraction patterns. A process for preparation of amorphous form of quinapril hydrochloride, substantially free of impurities, specially diketopiperazine compound, and conforming to pharmacopoeial specifications, using the novel crystalline quinapril hydrochloride as an intermediate. The process involves obtaining free base compound of formula (V) by adjusting the pH of a solution of the benzyl ester maleate salt of quinapril of formula (V) between 7.5-8.5 in a mixture of water and an organic solvent; catalytic hydrogenation of this compound (V) in an alcoholic solvent in the presence of concentrated hydrochloric acid or hydrogen chloride dissolved in an alcoholic solvent and in the presence of catalytic amounts of Pd/C to obtain a residue containing formula (I); crystallization of the said residue by evaporating the alcoholic solvent from a nitroalkane solvent to give crystalline quinapril hydrochloride, associated with a solvate of the nitroalkane solvent, and drying the crystalline quinapril hydrochloride nitroalkane solvate at a temperature between 40° C. and 45° C. under vacuum to give amorphous quinapril hydrochloride of formula (I).
一种新的晶体形式的
盐酸奎那普利,
化学式为(I)。一种无杂质的非晶态
盐酸奎那普利,特别是二酮肽化合物,符合药典规范,由所述新的晶体形式的
盐酸奎那普利化合物(I)形成。晶体
盐酸奎那普利以硝基烷溶剂的形式存在,其中硝基烷为
硝基甲烷,
硝基乙烷和
硝基丙烷。每种这样的硝基烷溶剂具有特定的X射线衍射图案。一种制备无杂质的非晶态
盐酸奎那普利的工艺,特别是二酮肽化合物,符合药典规范,使用新的晶体
盐酸奎那普利化合物作为中间体。该工艺包括通过在
水和有机溶剂的混合物中将奎那普利苄酯
马来酸盐的溶液的pH值调节在7.5-8.5之间,获得化合物(V)的游离碱基化合物;在含有浓
盐酸或氢
氯酸的
酒精溶剂中,在Pd/C的催化下催化氢化化合物(V);通过从硝基烷溶剂中蒸发
酒精溶剂来结晶所述残留物,得到与硝基烷溶剂的溶剂结晶的晶体
盐酸奎那普利,并在真空下在40°C和45°C之间干燥晶体
盐酸奎那普利硝基烷溶剂结晶,得到
化学式为(I)的非晶态奎那普利盐酸盐。