ChemicalBook CAS DataBase List Pramipexole Impurity 4

Pramipexole Impurity 4 synthesis

13synthesis methods

Product Name:Pramipexole Impurity 4
CAS Number:104632-25-9
Molecular formula:C10H19Cl2N3S
Molecular Weight:284.25

104632-26-0
303 suppliers
$8.00/50mg

104632-25-9
294 suppliers
$6.00/10mg

Yield:104632-25-9 98%

Reaction Conditions:

with hydrogenchloride in water;acetone at 0 - 3; pH=1.5; for 2 h;Product distribution / selectivity;

Steps:

8

Example 8 (S)-2-Amino-6-(n-propyl)amino-4,5,6,7-tetrahydrobenzothiazole dihydrochloride monohydrate, (S)-pramipexole dihydrochloride monohydrate (I·2 HCl·1 H₂O) A solution of (S)-pramipexole free base (Ia) (24.30 g) in acetone (730 ml) was cooled to 0-3°C, its pH was adjusted to 1.5 by the addition of 37% hydrochloric acid. The mixture was stirred at that temperature for 2 h and the precipitated crystals were collected by filtration. The cake was washed with cold acetone and air-dried to give 34.16 g (98%) product with m.p. 278-280°C. HPLC (purity, A%): 99.95%, [α]_D²⁰: -67.3 (c = 1.0, MeOH), optical purity (A%) (HPLC, using a chiral, optically active stationary phase): 99.6% ee.

References:

EP1878731,2008,A1 Location in patent:Page/Page column 11