Oxazole → ethyl 2-amino-5-bromothiazole-4-carboxylate

HRID 725005Notes

Reaction equation

HRID 725005 reaction equation
[NH2:1][C:2]1[S:3][CH:4]=[C:5]([C:7]([O:9][CH2:10][CH3:11])=[O:8])[N:6]=1.[Br:12]CC(=O)C(OCC)=O.NC(N)=S.O1C=CN=C1.BrBr.C(=O)([O-])[O-].[Na+].[Na+]>Br>[NH2:1][C:2]1[S:3][C:4]([Br:12])=[C:5]([C:7]([O:9][CH2:10][CH3:11])=[O:8])[N:6]=1

Participants

8

Reactant 6

HCID 9255OxazoleHCID 10340Sodium CarbonateHCID 24408BromineHCID 66144Ethyl bromopyruvateHCID 73216Ethyl 2-aminothiazole-4-carboxylateHCID 2723790Thiourea

Product 1

HCID 1284665ethyl 2-amino-5-bromothiazole-4-carboxylate

Reagents, catalysts & solvents 1

HCID 260Hydrogen BromideSolvent

Conditions

Temperature
60 °C

Procedure

Ethyl 2-aminothiazole-4-carboxylate (5.0 g) (prepared from ethyl bromopyruvate and thiourea by the procedure described in J. Med. Chem., 1971, 14, 1075 for the corresponding oxazole) in concentrated hydrobromic acid (9 cm3) was stirred at ambient temperature and treated dropwise with bromine (3.2 g), then heated to 60° C. for 2 hours, neutralised with sodium carbonate and the product extracted into ethyl acetate. The organic phase was dried (MgSO4)and evaporated under reduced pressure to give ethyl 2-amino-5-bromothiazole-4-carboxylate (1.54 g). MH+ =251; 1H NMR: δ 1.40(3H,t); 4.40(2H,t); 5.6(2H,br s).

Workup

  1. extractionthe product extracted into ethyl acetate
  2. customevaporated under reduced pressure

Sources & evidence

ORD record
ord-07d1ff44247c4f2f8b48c01154e6031e
Source dataset
uspto-grants-1998_01
Patent number
US05705516

Reaction notes

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