Potassium Hydroxide → Pemirolast potassium

HRID 48463Notes

Reaction equation

HRID 48463 reaction equation
[CH3:1][C:2]1[C:7]2=[N:8][CH:9]=[C:10]([C:13]3[NH:17][N:16]=[N:15][N:14]=3)[C:11](=[O:12])[N:6]2[CH:5]=[CH:4][CH:3]=1.[OH-].[K+:19]>CO>[CH3:1][C:2]1[C:7]2=[N:8][CH:9]=[C:10]([C:13]3[N-:17][N:16]=[N:15][N:14]=3)[C:11](=[O:12])[N:6]2[CH:5]=[CH:4][CH:3]=1.[K+:19]

Participants

4

Reactant 2

HCID 14797Potassium HydroxideHCID 178426257HCID 178426257, compound

Product 1

HCID 443866Pemirolast potassiumYield 96%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Conditions

Temperature
45 °C

Procedure

9-Methyl-3-(1 H-tetrazol-5-yl)-4H-pyrido-[1,2-a]-pyrimidin-4-one (63 g, 0.28 mols) is suspended in methanol (1000 ml). The resulting suspension is kept at 45° C. and slowly added with a 45% potassium hydroxide aqueous solution to pH 9-9.5. The suspension is stirred at 45° C. for about 15 minutes and then cooled to 20° C. The precipitate is filtered, washed with methanol and dried under vacuum at 80° C., to obtain Pemirolast Potassium (71.9 g; 0.27 mols, 96% yield) with HPLC purity >99.8%. 1H NMR(D2O, TMS) d (ppm): 2.02 (s, 3H); 6.83 (t, 1H); 7.22 (d, 1H); 8.18 (s, 1H); 8.47 (d, 1H).

Workup

  1. customis kept at 45° C.
  2. temperaturecooled to 20° C
  3. filtrationThe precipitate is filtered
  4. washwashed with methanol
  5. customdried under vacuum at 80° C.

Sources & evidence

ORD record
ord-141172b7bb8e43b6ad910ebed82746fa
Source dataset
uspto-grants-2004_03
Patent number
US06703505B2

Reaction notes

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