Reaction #76018

Reaction equation

ethyl (2S)-6-{[(benzyloxy)-carbonyl]amino}-2-{[(tert-butylamino)carbothioyl]-amino}hexanoate

hydrochloric acid

→

(−)-(4S)-4-(4-Aminobutyl)-4,5-dihydro-1,3-thiazol-2-ylamine dihydrochloride

Solvents

diethyl ether

Conditions

Workup

1. 1
   OtherAfter concentration of the reaction medium under the same conditions, the foam obtained
2. 2
   Otherthe phases are separated each time after settling
3. 3
   FiltrationThe resulting crystalline product is spin-filtered
4. 4
   Washwashed with hot acetonitrile
5. 5
   Otherdried under reduced pressure (5 kPa) at a temperature in the region of 20° C

Procedure

The process is performed as in Example 9, starting with 0.59 g of ethyl (2S)-6-{[(benzyloxy)-carbonyl]amino}-2-{[(tert-butylamino)carbothioyl]-amino}hexanoate in 6 cm3 of 6N hydrochloric acid. After concentration of the reaction medium under the same conditions, the foam obtained is taken up 3 times in diethyl ether and the phases are separated each time after settling has taken place, and the remaining insoluble material is then taken up in 10 cm3 of acetonitrile. The resulting crystalline product is spin-filtered, washed with hot acetonitrile and then dried under reduced pressure (5 kPa) at a temperature in the region of 20° C. 0.34 g of (−)-(4S)-4-(4-amino-butyl)-4,5-dihydro-1,3-thiazol-2-ylamine dihydro-chloride in the form of cream-colored crystals melting at 170° C. (αD20=−15.5±0.6 at a concentration of 0.5% in methanol).

Source