Abstract: 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%.

Abstract: 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”.

Abstract: 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?-(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?-(thien-2-yl-)ethyl-tetralin-2-amine, which is then dissociated to obtain S-5-substituted-N-2?-(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).

Abstract: The present invention relates to a process for preparing tolterodine and the L-tartrate thereof. The preparation consists of the following steps: A) ammonolysis reaction between diisopropylamine and compound 2 (3,4-dihydro-6-methyl-4-phenyl-2H-benzopyran-2-one) activated by an activator to afford the amide 3; B) reduction of the amide by a reductant to give compound 1, i.e., racemic tolterodine free base; C) Resolution of the tolterodine free base to afford tolterodine L-tartrate. The present route is very short and suitable for industrial production.