Richter Gedeon Vegyeszeti Gyar Rt

Gabor Tarkanyi

Tibor Gizur

Jozsef Törley

Bela Hegedus

Maria Gazdag

Attila Szemzo

Jozsef Neu

Janos Csabai

Ferenc Vegh

Peter Kalvin

Monika Babjak

The invention relates to N-(trans-4-isopropylcyclohexylcarbonyl)-D-phenylalanine (nateglinide) in the novel crystalline form 'G' and a process for the preparation thereof. A process for the preparation of chirally pure nateglinide by treating a lower alkyl ester thereof with a base to yield an alkali salt and liberating the product from said salt by proper addition of an acid, is also provided. Still another aspect of the invention is a process for the preparation of nateglinide in the crystalline form 'H' from other crystalline modifications of nateglinide.

Process for the preparation of chirally pure N-(trans-4-is)

The present invention relates to a new process for the synthesis of high purity 3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine of formula (I) using 2,3-dichlorobenzoyl cyanide and an aminoguanidine salt as starting materials. 2,3-dichlorobenzoyl cyanide is reacted with 1-2 mol equivalent of aminoguanidine salt in 3-6 mol equivalent of methanesulfonic acid, then the obtained adduct of formula (IV) is transformed without isolation into the product with magnesium oxide. In given case the obtained crude product can be recrystallized from a proper organic solvent 

Process for the synthesis of high purity 3,5-diamino-6-(2,3-dichlorophenyl) (1,2,4-triazine)

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Budaörs, Hungary

Gabor Tarkanyi