1-Bromopropane → Benzoic Acid

HRID 1265239Notes

Reaction equation

HRID 1265239 reaction equation
C[O:2][C:3](=[O:27])[C:4]1[CH:9]=[CH:8][C:7](C(C2C(O)=CC3C(C)(C)CCC(C)(C)C=3C=2)=O)=[CH:6][CH:5]=1.[OH-].[K+].BrCCC>CS(C)=O>[C:3]([OH:27])(=[O:2])[C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1

Participants

5

Reactant 3

HCID 78401-BromopropaneHCID 14797Potassium HydroxideHCID 10021814HCID 10021814, compound

Product 1

HCID 243Benzoic AcidYield 233.9%

Reagents, catalysts & solvents 1

HCID 679Dimethyl SulfoxideSolvent2×

Procedure

A solution of the 4-[(3-hydroxy,5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)carbonyl]benzoic acid methyl ester (from Example 7, 433 mg, 1.18 mmol) in DMSO (2 mL) was treated with KOH (1.5 mmol) at 0° C. and allowed to warm to ambient temperature over 1 h. The yellow solution was cooled again to 0° C., and treated with a solution of bromopropane (118 mL, 1.30 mmol) in DMSO (1mL) and allowed to warm to ambient temperature and stirred for 10 h. The reaction was quenched with saturated aqueous NH4Cl. The aqueous solution was adjusted to pH=3 with 1M HCl and extracted with EtOAc, 3×. The organic layers were combined and washed with water (2×) and brine. The organic solution was dried (NaSO4), filtered, and concentrated. Purification by silica gel radial chromatography (20:1=hexanes:Et2O) gave 4-[2-propoxy-5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)carbonyl]benzoic acid 337 mg (75%) as a coloreless oil: 1H NMR (400 MHz, CDCl3) δ8.15 (½ABq, J=8.2 Hz, 2H, ArH), 7.85 (½ABq, J=8.2 Hz, 2H, ArH), 7.46 (s, 1H, ArH), 6.82 (s, 1H, ArH), 3.78 (t, J=6.3 Hz, 2H, OCH2), 1.70 (m, 4H, 2CH2), 1.36 (m, 2H, CH2), 1.32 (s, 6H, 2CH3), 1.28 (s, 6H, 2CH3), 0.62 (t, J=7.4 Hz, 3H, CH3). The propoxyketo acid (1.34 mg, 0.33 mmol) in EtOH (2mL) was converted to the oxime derivative as described in Example 4 to provide, after recrystallization (CH2Cl2/hexanes (4-[(3-propoxy-5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)carbonyl]benzoic acid oxime (109) (97%) as a white solid: mp 251-255° C. (d); 1H NMR (400 MHz, CDCl3) δ7.98 (½ABq, J=8.4 Hz, 2H, ArH), 7.54 (½ABq, J=8.4 Hz, 2H, ArH), 7.13 (s, 1H, ArH), 6.86 (s, 1H, ArH), 3.81 (t, J=6.2 Hz, 2H, OCH2), 1.70 (m, 4H, 2CH2), 1.51 (m, 2H, CH2), 1.32 (s, 6H, 2CH3), 1.24 (s, 6H, 2CH3), 0.72 (t, J=7.4 Hz, 3H, CH3).

Workup

  1. temperatureThe yellow solution was cooled again to 0° C.
  2. temperatureto warm to ambient temperature
  3. customThe reaction was quenched with saturated aqueous NH4Cl
  4. extractionextracted with EtOAc, 3×
  5. washwashed with water (2×) and brine
  6. dry with materialThe organic solution was dried (NaSO4)
  7. filtrationfiltered
  8. concentrationconcentrated
  9. customPurification by silica gel radial chromatography (20:1=hexanes:Et2O)

Sources & evidence

ORD record
ord-87ade04f4218488eae483ea63642f876
Source dataset
uspto-grants-2003_04
Patent number
US06545049B1

Reaction notes

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