Nitrogen → Ethyl 5-bromo-1-benzofuran-3-carboxylate

HRID 595633Notes

Reaction equation

HRID 595633 reaction equation
[CH3:1][CH2:2][O:3][CH2:4][CH3:5].[Br:6][C:7]1[CH:8]=[CH:9]C(O)=C([CH:14]=1)C=O.[N+](=C[C:19]([O:21][CH2:22][CH3:23])=[O:20])=[N-].N#N.OS(O)(=O)=O.C([O-])([O-])=O.[Na+].[Na+]>C(Cl)Cl>[Br:6][C:7]1[CH:14]=[CH:5][C:4]2[O:3][CH:2]=[C:1]([C:19]([O:21][CH2:22][CH3:23])=[O:20])[C:9]=2[CH:8]=1

Participants

8

Reactant 6

HCID 947NitrogenHCID 1118Sulfuric AcidHCID 3283Diethyl EtherHCID 10340Sodium CarbonateHCID 12192Ethyl diazoacetateHCID 728635-Bromosalicylaldehyde

Product 1

HCID 21694192Ethyl 5-bromo-1-benzofuran-3-carboxylateYield 373.5%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

Et2O (16.2 g, 99.5 mmol) was added to a solution of 5-bromo-2-hydroxybenzaldehyde (200 g, 995 mmol) in CH2Cl2 (500 mL), and then a solution of ethyl diazoacetate (180 g, 1.42 mol) in CH2Cl2 (500 mL) was introduced as evolution of N2 gas while the reaction was not allowed over 38° C. Once gas evolution ceased, the reaction mixture was concentrated by rotary evaporator and conc. H2SO4 (129 g, 1.29 mol, 98%) was added to the mixture while stirring. After 20 minutes, the acidic mixture was neutralized with Na2CO3 (a.q). After the mixture was stored and crystallized overnight, ethyl 5-bromobenzofuran-3-carboxylate (100 g, yield: 75%) was obtained by filtration. 1H-NMR (CDCl3, 400 MHz) δ 8.25 (s, 1H), 8.15˜8.21 (m, 1H), 7.44˜7.50 (m, 1H), 7.37˜7.42 (m, 1H), 4.41 (q, J=7.2 Hz, 2H), 1.43 (t, J=7.2 Hz, 3H). MS (M+H)+: 269/271.

Workup

  1. customwas not allowed over 38° C
  2. additionwas added to the mixture
  3. customcrystallized overnight

Sources & evidence

ORD record
ord-78f212f2ed81474e875b7fced0be13c1
Source dataset
uspto-grants-2016_01
Patent number
US09243002B2

Reaction notes

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