Potassium Bromide → 2-(4-Chloro-phenyl)-4-(2-oxo-ethyl)-thiazole-5-carboxylic acid methyl ester

HRID 554838Notes

Reaction equation

[CH3:1][O:2][C:3]([C:5]1[S:9][C:8]([C:10]2[CH:15]=[CH:14][C:13]([Cl:16])=[CH:12][CH:11]=2)=[N:7][C:6]=1[CH2:17][CH2:18][OH:19])=[O:4].[Br-].[K+].Cl[O-].[Na+].C(=O)(O)[O-].[Na+]>C(Cl)Cl.O.CC1(C)N([O])C(C)(C)CCC1>[CH3:1][O:2][C:3]([C:5]1[S:9][C:8]([C:10]2[CH:15]=[CH:14][C:13]([Cl:16])=[CH:12][CH:11]=2)=[N:7][C:6]=1[CH2:17][CH:18]=[O:19])=[O:4]

Participants

Conditions

Temperature: -10 °C

Procedure

Dissolve 2-(4-chloro-phenyl)-4-(2-hydroxy-ethyl)-thiazole-5-carboxylic acid methyl ester (100 g, 336 mmol) in CH2Cl2 (2 L) and treat with potassium bromide (4.0 g, 33.6 mmol) and TEMPO (1.1 g, 7.0 mmol). Cool the solution to −10° C. and add a solution of sodium hypochlorite (1 L, 0.25 M in water) and aqueous sodium bicarbonate (1 L, 1.4 M). Stir the resulting slurry at 0° C. for 15 min and then dilute with water (3.2 L) and CH2Cl2 (1.3 L). Remove the organic solution and extract the aqueous phase with CH2Cl2 (1.3 L). Combine the organic solutions and wash with brine (1.3 L), then dry, filter, and concentrate to give (91.5 g, 92%) of the title compound. 1H NMR (400 MHz, CDCl3): δ 9.86 (t, J=1.5 Hz, 1H), 7.90 (dt, J=8.4, 4.4 Hz, 2H), 7.43 (dt, J=8.6, 4.4 Hz, 2H), 4.32 (d, J=1.8 Hz, 2H), 3.89 (s, 3H).

Workup

customRemove the organic solution
extractionextract the aqueous phase with CH2Cl2 (1.3 L)
washCombine the organic solutions and wash with brine (1.3 L)
customdry
filtrationfilter
concentrationconcentrate

Sources & evidence

ORD record: ord-f1dc37fd3287420ab75aa18a900e63e9
Source dataset: uspto-grants-2011_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08049013B2

Reaction notes

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