Boron tribromide → 2-Tert-butoxycarbonylmethyl-5-methyl benzoic acid tert-butyl ester

HRID 1170038Notes

Reaction equation

HRID 1170038 reaction equation
[C:1]([CH2:4][C:5]1[CH:13]=[CH:12][C:11]([CH3:14])=[CH:10][C:6]=1[C:7]([OH:9])=[O:8])([OH:3])=[O:2].ClC(Cl)(Cl)C(=N)O[C:19]([CH3:22])([CH3:21])[CH3:20].B(Br)(Br)Br.C([O-])(O)=O.[Na+]>ClCCl.C1CCCCC1>[C:5]([O:8][C:7](=[O:9])[C:6]1[CH:10]=[C:11]([CH3:14])[CH:12]=[CH:13][C:5]=1[CH2:4][C:1]([O:3][C:19]([CH3:20])([CH3:21])[CH3:22])=[O:2])([CH3:13])([CH3:6])[CH3:4]

Participants

7

Reactant 4

HCID 25134Boron tribromideHCID 516892Sodium BicarbonateHCID 2734700Tert-butyl 2,2,2-trichloroethanimidateHCID 125931292-(Carboxymethyl)-5-methylbenzoic acid

Product 1

HCID 121113512-Tert-butoxycarbonylmethyl-5-methyl benzoic acid tert-butyl esterYield 166.7%

Reagents, catalysts & solvents 2

HCID 6344DichloromethaneSolventHCID 8078CyclohexaneSolvent

Procedure

To a suspension of 2-carboxymethyl-5-methyl-benzoic acid (2.544 g, 13.1 mmol) in anhydrous dichloromethane (70 ml) held at 0° C. was added tert-butyl 2,2,2-trichloroacetimidate (11.47 mg, 52.4 mmol, 2 equivalents) in cyclohexane (85 ml). BBr3 (0.52 ml) was then added, and the reaction mixture was raised to room temperature and stirred for 16 hr. Solid NaHCO3 was added to quench the reaction, the solid precipitate was filtered off and washed with ether. The combined organic washing was evaporated to dryness, and the residue obtained was purified by silica gel chromatography to obtain 2-tert-butoxycarbonylmethyl-5-methyl benzoic acid tert-butyl ester 3.345 g (83.3%) as an oil. 1H NMR (CDCl3): 7.718 (1H, s), 7.227 (1H, d, J=7.57 Hz), 3.910 (2H, s), 2.362 (3H, s), 1.584 (9H, s), 1.443 (9H, s). FABMS (+Ve), m/z 307 [MH+], 251 [MH+−C4H8], 195 [MH+−2C4H8]. Anal. calcd. for C18H26O4: C, 70.6; H, 8.6. Found: C, 70.82; H, 8.53.

Workup

  1. customheld at 0° C.
  2. customto quench
  3. customthe reaction
  4. filtrationthe solid precipitate was filtered off
  5. washwashed with ether
  6. washThe combined organic washing
  7. customwas evaporated to dryness
  8. customthe residue obtained
  9. customwas purified by silica gel chromatography

Sources & evidence

ORD record
ord-012f2d93c5404fb6ab7238462bd43b6a
Source dataset
uspto-grants-2010_11
Patent number
US07825216B2

Reaction notes

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