2y-chem, Ltd.

Contravir Pharmaceuticals, Inc.

Xungui He

Lei Zhang

Yanling Wang

Jie Li

Wensheng Tang

Chuanjun Liu

Xuezhang Wang

Jirang Zhu

Qingzhong Cheng

Mingyong Yuan

Yong Liang Liu

Jianping Guo

Yanfeng Zhou

Xingzhong Zhang

Jinfeng Song

Yuan Wang

The present invention relates to 2-isopropoxy-5-methyl-4-(piperidin-4-yl) aniline dihydrochloride monohydrate and a preparation method of the same. The 2-isopropoxy-5-methyl-4-(piperidin-4-yl) aniline dihydrochloride monohydrate has a very good crystal form and is well suitable for recrystallization purification; further, the effect of impurity removal effect is very good, and any single impurity can be controlled less than 0.1%.

Hydrate of 2-isopropoxy-5-methyl-4-(piperidin-4-yl) aniline dihydrochloride, preparation method and use of the same

The invention is directed to processes for synthesizing bicyclic nucleoside antiviral compounds and for synthesizing the intermediates used in the process. The invention is also directed to novel intermediate compounds useful in the process. The antiviral compounds are useful in the treatment of herpes zoster (i.e., varicella zoster virus, VZV, shingles) and for the prevention of post herpetic neuralgia (PHN) resulting from this viral infection.

Method of preparation of antiviral compounds and useful intermediates thereof

The present invention discloses an improved process for preparing an important intermediate of linagliptin. In particular, disclosed are a process for preparing a compound V which is an important intermediate of linagliptin and has the structure V, and an industrial process of preparing linagliptin having excellent chemical and optical purities, which is an inhibitor of dipeptidyl peptidase-4 (DPP-IV), from the compound V. The process employs a phase-transfer catalyst, is high in yield, easy and simple to handle, environmentally friendly, suitable for industrial mass production, and can be implemented by a 'one-pot process'. 

Method for preparing an important intermediate of linagliptin

The chiral compound S-5-substituted-N-2'-(thienyl-2-yl-)ethyl-tetralin-2-amine or its chiral acid salts and preparation method thereof are disclosed, and the method for preparing Rotigotine by using the chiral compound is also disclosed. Racemic 5-substituted-N-2&#x2032;-(thien-2-yl-)ethyl-tetralin-2-amine (compound 1) is resolved by using a conventional chiral acid to obtain an optically pure chiral acid salt of S-5-substituted-N-2&#x2032;-(thien-2-yl-)ethyl-tetralin-2-amine, which is then dissociated to obtain S-5-substituted-N-2&#x2032;-(thien-2-yl-)ethyl-tetralin-2-amine (compound 2). The compound 2 or chiral acid salt thereof is alkylated and deprotected to produce rotigotine (compound 5). 

S-5-substituent-N-2'-(thiophene-2-yl)ethyl-tetralin-2-amine or chiral acid salts thereof and use for preparing Rotigotine

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Shanghai, China

Xungui He