2-Methoxyethanol → 2-(5-Methylthien-2-yl)imidazo[2,1-b]benzothiazole-3-acetic acid

HRID 36907

Reaction equation

HRID 36907 reaction equation
CN(C)[C:3](=[O:23])[CH2:4][C:5]1[N:12]2[C:8]([S:9][C:10]3[CH:16]=[CH:15][CH:14]=[CH:13][C:11]=32)=[N:7][C:6]=1[C:17]1[S:18][C:19]([CH3:22])=[CH:20][CH:21]=1.C[O:26]CCO.[OH-].[Na+]>O>[CH3:22][C:19]1[S:18][C:17]([C:6]2[N:7]=[C:8]3[N:12]([C:5]=2[CH2:4][C:3]([OH:23])=[O:26])[C:11]2[CH:13]=[CH:14][CH:15]=[CH:16][C:10]=2[S:9]3)=[CH:21][CH:20]=1

Participants

5

Reactant 3

HCID 80192-MethoxyethanolHCID 14798Sodium Hydroxide2×HCID 9884996N,N-Dimethyl-2-(5-methylthien-2-yl)imidazo[2,1-b]-benzothiazole-3-acetamide

Product 1

HCID 152338102-(5-Methylthien-2-yl)imidazo[2,1-b]benzothiazole-3-acetic acid

Reagents, catalysts & solvents 1

HCID 962WaterSolvent2×

Conditions

Temperature
130 °C

Procedure

23.8 g (0.067 mole) of N,N-dimethyl-2-(5-methylthien-2-yl) imidazo[2,1-b]benzothiazole-3-acetamide and 450 ml of 2-methoxyethanol are introduced into a 1 liter round-bottomed flask, and the mixture is stirred and it is heated on an oil bath at around 130° C. until the solid dissolves. A solution of 13.4 g (0.335 mole) of sodium hydroxide pellets in 70 ml of water is added hot, with precaution, then after 30 minutes, a further 13.4 g (0.335 mole) of sodium hydroxide pellets in 70 ml of water, and the heating is maintained for 7 h 30 min, while monitoring the progress of the reaction by thin-layer chromatography. The mixture is cooled to around 20° C., the solvent is evaporated under reduced pressure, without exceeding 60° C. 1200 ml of water are added to the residue, an insoluble matter is removed by filtration, 150 ml of acetic acid are added to the filtrate up to a pH=4. A yellow-coloured precipitate is obtained which is stirred for 30 minutes while cooling to around 5° C. The solid is separated by filtration, it is washed with water and then with diethyl ether, and it is dried under vacuum at around 60° C. 17.5 g of compound are obtained of which 1.65 g (0.005 mole) are purified by recrystallization from 250 ml of boiling methanol. 1.1.g of a light yellow-coloured solid are isolated. Melting point: 255°-259° C.

Workup

  1. dissolutiondissolves
  2. customthe progress of the reaction by thin-layer chromatography
  3. temperatureThe mixture is cooled to around 20° C.
  4. customthe solvent is evaporated under reduced pressure
  5. customwithout exceeding 60° C
  6. addition1200 ml of water are added to the residue
  7. customan insoluble matter is removed by filtration, 150 ml of acetic acid
  8. additionare added to the filtrate up to a pH=4
  9. customA yellow-coloured precipitate is obtained which
  10. stirringis stirred for 30 minutes
  11. temperaturewhile cooling to around 5° C
  12. customThe solid is separated by filtration, it
  13. washis washed with water
  14. dry with materialwith diethyl ether, and it is dried under vacuum at around 60° C

Sources & evidence

ORD record
ord-ea296c106958469c86c8d1a1ea4f5124
Source dataset
uspto-grants-1995_05
Patent number
US05418248

Linked notes

Loading…