Dimethylformamide → Methyl 2-chloro-1,3-benzoxazole-7-carboxylate

HRID 1990879Notes

Reaction equation

HRID 1990879 reaction equation
[CH3:1][O:2][C:3]([C:5]1[C:13]2[O:12][C:11](S)=[N:10][C:9]=2[CH:8]=[CH:7][CH:6]=1)=[O:4].S(Cl)([Cl:17])=O.CN(C=O)C>>[CH3:1][O:2][C:3]([C:5]1[C:13]2[O:12][C:11]([Cl:17])=[N:10][C:9]=2[CH:8]=[CH:7][CH:6]=1)=[O:4]

Participants

4

Reactant 3

HCID 6228DimethylformamideHCID 24386Thionyl ChlorideHCID 178497587HCID 178497587, compound

Product 1

HCID 68406054Methyl 2-chloro-1,3-benzoxazole-7-carboxylateYield 81%

Procedure

To 2-mercapto-benzooxazole-7-carboxylic acid methyl ester (1.0 g, 4.78 mmol, 1.0 equiv) was added thionyl chloride (8.0 g, 4.9 mL, 67.6 mmol, 14.0 equiv) and anhydrous DMF (0.4 g, 0.4 mL, 5.19 mmol, 1.1 equiv) and the reaction mixture heated to reflux for 15 min. The solvent was removed under reduced pressure, the crude oil azeotroped twice with xylene and the crude material purified with column chromatography on silica eluting with ethyl acetate/hexane (1:1) to afford 0.81 g (81%) of the title compound. 1H NMR (300 MHz, CDCl3): δ 4.03 (s, 3H), 7.44 (t, J=7.9 Hz, 1H), 7.87 (dd, J=7.9 Hz, J=1.1 Hz, 1H), 8.01 (dd, J=7.9 Hz, J=1.1 Hz, 1H). 13C NMR (75 MHz, CDCl3): δ 52.46, 115.07, 124.36, 124.82, 127.54, 142.39, 150.35, 152.24, 163.88. MS (ISP): 212.0 [M+H]+.

Workup

  1. temperaturethe reaction mixture heated
  2. temperatureto reflux for 15 min
  3. customThe solvent was removed under reduced pressure
  4. customthe crude oil azeotroped twice with xylene
  5. customthe crude material purified with column chromatography on silica eluting with ethyl acetate/hexane (1:1)

Sources & evidence

ORD record
ord-8b69a0d22859446080dae4ac9172f6e5
Source dataset
uspto-grants-2010_01
Patent number
US07645753B2

Reaction notes

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