Boron tribromide → (2R,4S)-5-biphenyl-4-yl-4-(3,5-difluoro-4-hydroxy-benzoylamino)-2-methyl-pentanoic acid ethyl ester

HRID 1469615Notes

Reaction equation

HRID 1469615 reaction equation
[CH2:1]([O:3][C:4](=[O:35])[C@H:5]([CH3:34])[CH2:6][C@H:7]([NH:21][C:22](=[O:33])[C:23]1[CH:28]=[C:27]([F:29])[C:26]([O:30]C)=[C:25]([F:32])[CH:24]=1)[CH2:8][C:9]1[CH:14]=[CH:13][C:12]([C:15]2[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=2)=[CH:11][CH:10]=1)[CH3:2].B(Br)(Br)Br>C(Cl)Cl>[CH2:1]([O:3][C:4](=[O:35])[C@H:5]([CH3:34])[CH2:6][C@H:7]([NH:21][C:22](=[O:33])[C:23]1[CH:24]=[C:25]([F:32])[C:26]([OH:30])=[C:27]([F:29])[CH:28]=1)[CH2:8][C:9]1[CH:10]=[CH:11][C:12]([C:15]2[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=2)=[CH:13][CH:14]=1)[CH3:2]

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 59608113(2R,4S)-5-biphenyl-4-yl-4-(3,5-difluoro-4-methoxy-benzoylamino)-2-methyl-pentanoic acid ethyl ester

Product 1

HCID 67506121(2R,4S)-5-biphenyl-4-yl-4-(3,5-difluoro-4-hydroxy-benzoylamino)-2-methyl-pentanoic acid ethyl esterYield 82.3%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

Next, to a solution of (2R,4S)-5-biphenyl-4-yl-4-(3,5-difluoro-4-methoxy-benzoylamino)-2-methyl-pentanoic acid ethyl ester (125 mg, 0.260 mmol) in DCM (2.6 mL) is slowly added BBr3 (2.60 mL, 2.60 mmol) under nitrogen. The reaction is stirred for 18 hours at rt. The reaction is quenched with MeOH, diluted with EtOAc, washed with H2O and brine, dried over MgSO4, and concentrated under reduced pressure. The obtained material is purified by preparative silica gel thin-layer chromatography (7% MeOH in DCM) to give 100 mg (2R,4S)-5-biphenyl-4-yl-4-(3,5-difluoro-4-hydroxy-benzoylamino)-2-methyl-pentanoic acid ethyl ester. Next, to a solution of (2R,4S)-5-biphenyl-4-yl-4-(3,5-difluoro-4-hydroxy-benzoylamino)-2-methyl-pentanoic acid ethyl ester (30 mg, 0.064 mmol) in MeOH (2 mL) at room temperature is added aqueous 1M NaOH (4 mL, 4.0 mmol). After stirring for 1 hour the reaction is quenched with aqueous 1M HCl (4 mL, 4.0 mmol). The mixture is concentrated under reduced pressure and filtered to remove NaCl salt. The obtained residue is purified by preparative silica gel thin-layer chromatography (7% MeOH in DCM) to give 17.1 mg of (2R,4S)-5-biphenyl-4-yl-4-(3,5-difluoro-4-hydroxy-benzoylamino)-2-methyl-pentanoic acid. HPLC Retention time 1.56 minutes (condition B); MS 440 (M+1); 1H NMR (400 MHz, ACETONITRILE-d3) δ ppm 1.19 (d, J=7.07 Hz, 3 H) 1.55 (ddd, J=14.27, 10.74, 3.79 Hz, 1 H) 1.90-1.96 (m, 1 H) 2.54-2.71 (m, 1 H) 2.91 (dd, J=6.69, 3.16 Hz, 2 H) 4.25-4.43 (m, 1 H) 6.49 (d, J=9.60 Hz, 2 H) 6.93 (d, J=8.84 Hz, 1 H) 7.33-7.42 (m, 3 H) 7.49 (t, J=7.71 Hz, 2 H) 7.61 (d, J=8.34 Hz, 2 H) 7.67 (dd, J=8.34, 1.26 Hz, 2 H).

Workup

  1. customThe reaction is quenched with MeOH
  2. additiondiluted with EtOAc
  3. washwashed with H2O and brine
  4. dry with materialdried over MgSO4
  5. concentrationconcentrated under reduced pressure
  6. customThe obtained material is purified by preparative silica gel thin-layer chromatography (7% MeOH in DCM)

Sources & evidence

ORD record
ord-0028ee04e66d4e64a0a324ea45f8ef83
Source dataset
uspto-grants-2015_04
Patent number
US09006249B2

Reaction notes

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