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

HRID 1765443Notes

Reaction equation

HRID 1765443 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 [MH30 —2C4H4]. 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-b051b681e93c4c79a1ad34dcbf1eb783
Source dataset
uspto-grants-2007_06
Patent number
US07226991B1

Reaction notes

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