Carbon Dioxide → Imidazo[5,1-b][1,3]thiazole-7-carboxylic acid

HRID 989842Notes

Reaction equation

HRID 989842 reaction equation
C([Mg]Br)C.C1COCC1.I[C:11]1[N:12]=[CH:13][N:14]2[CH:18]=[CH:17][S:16][C:15]=12.[C:19](=[O:21])=[O:20].[OH-].[Na+]>C1COCC1.CCOCC>[S:16]1[CH:17]=[CH:18][N:14]2[CH:13]=[N:12][C:11]([C:19]([OH:21])=[O:20])=[C:15]12

Participants

7

Reactant 4

HCID 280Carbon DioxideHCID 14798Sodium HydroxideHCID 177737777-Iodoimidazo[5,1-B]thiazoleHCID 178420660HCID 178420660, compound

Product 1

HCID 23449010Imidazo[5,1-b][1,3]thiazole-7-carboxylic acidYield 83.7%

Reagents, catalysts & solvents 2

HCID 3283Diethyl EtherSolventHCID 8028TetrahydrofuranSolvent

Procedure

A 0.95 M ethylmagnesium bromide/THF solution (12.6 ml) was added dropwise to a solution (50 ml) of 2.501 g of 7-iodoimidazo[5,1-b]thiazole in THF at −70° C. The mixture was stirred for 30 min. Carbon dioxide (which had been evolved from about 5 g of dry ice and passed through a calcium chloride tube) was introduced into the reaction solution at the same temperature over a period of 40 min. The reaction solution was allowed to stand at −20° C. overnight, and then added to an ice cold mixed solution composed of an aqueous sodium hydroxide (0.41 g) solution (100 ml) and ether (200 ml) with stirring. The mixture was stirred for one hr. The organic layer was separated and concentrated under the reduced pressure by a minor amount, and the remaining organic solvent was removed by distillation. The residue was adjusted to pH 3.5 by the addition of 2 N hydrochloric acid under ice cooling. The resultant precipitate was washed with a minor amount of cold water, and then dried under the reduced pressure to give 1.407 g of imidazo[5,1-b]thiazole-7-carboxylic acid.

Workup

  1. waitto stand at −20° C. overnight
  2. stirringwith stirring
  3. stirringThe mixture was stirred for one hr
  4. customThe organic layer was separated
  5. concentrationconcentrated under the reduced pressure by a minor amount
  6. customthe remaining organic solvent was removed by distillation
  7. additionThe residue was adjusted to pH 3.5 by the addition of 2 N hydrochloric acid under ice cooling
  8. washThe resultant precipitate was washed with a minor amount of cold water
  9. customdried under the reduced pressure

Sources & evidence

ORD record
ord-693cbf7ee3224c73b9fa651c6c518085
Source dataset
uspto-grants-2002_10
Patent number
US06458780B1

Reaction notes

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