Acetic Acid → Tizanidine hydrochloride

HRID 451343Notes

Reaction equation

HRID 451343 reaction equation
[CH:1]1[C:6]2=[N:7][S:8][N:9]=[C:5]2[C:4]([NH:10][C:11]2[NH:15][CH2:14][CH2:13][N:12]=2)=[C:3]([Cl:16])[CH:2]=1.C(O)(=O)C>CC(C)=O>[CH:1]1[C:6]2=[N:7][S:8][N:9]=[C:5]2[C:4]([NH:10][C:11]2[NH:15][CH2:14][CH2:13][N:12]=2)=[C:3]([Cl:16])[CH:2]=1.[ClH:16]

Participants

4

Reactant 2

HCID 176Acetic AcidHCID 5487Tizanidine

Product 1

HCID 114869Tizanidine hydrochlorideYield 189.4%

Reagents, catalysts & solvents 1

HCID 180AcetoneSolvent

Conditions

Temperature
75 °C

Procedure

12.0 g of the tizanidine base (99.15% HPLC) are added to 26 ml of acetic acid. The resulting suspension is dissolved under stirring and heating at ca. 70 to 80° C. 55 ml of acetone and 1 g of active coal are added to this solution and after stirring for 15 minutes the solution is filtered. The hot filtrate is acidified by addition of 10 ml of isopropanolic hydrogen chloride. Shortly thereafter quick crystallization of tizanidine hydrochloride occurs, which is completed by cooling to 0 to 5° C. After aspiration 13.0 g of tizanidine hydrochloride (i.e. 95.0% th.) are obtained, purity 99.95% HPLC, colour GY6.

Workup

  1. dissolutionThe resulting suspension is dissolved
  2. stirringafter stirring for 15 minutes the solution
  3. filtrationis filtered
  4. additionThe hot filtrate is acidified by addition of 10 ml of isopropanolic hydrogen chloride
  5. customShortly thereafter quick crystallization of tizanidine hydrochloride
  6. temperatureby cooling to 0 to 5° C

Sources & evidence

ORD record
ord-9d0a74b96f3642288d973b0f21eadba7
Source dataset
uspto-grants-2013_07
Patent number
US08487113B2

Reaction notes

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