Boron tribromide → ethyl(E)-3-{2-[3-(1-adamantyl)-4-hydroxyphenyl]-5-pyrazinyl}-2-propenoate

HRID 508663Notes

Reaction equation

HRID 508663 reaction equation
[C:1]12([C:11]3[CH:12]=[C:13]([C:25]4[CH:30]=[N:29][C:28](/[CH:31]=[CH:32]/[C:33]([O:35][CH2:36][CH3:37])=[O:34])=[CH:27][N:26]=4)[CH:14]=[CH:15][C:16]=3[O:17]CC3C=CC=CC=3)[CH2:10][CH:5]3[CH2:6][CH:7]([CH2:9][CH:3]([CH2:4]3)[CH2:2]1)[CH2:8]2.B(Br)(Br)Br>C(Cl)Cl>[C:1]12([C:11]3[CH:12]=[C:13]([C:25]4[CH:30]=[N:29][C:28](/[CH:31]=[CH:32]/[C:33]([O:35][CH2:36][CH3:37])=[O:34])=[CH:27][N:26]=4)[CH:14]=[CH:15][C:16]=3[OH:17])[CH2:2][CH:3]3[CH2:4][CH:5]([CH2:6][CH:7]([CH2:9]3)[CH2:8]1)[CH2:10]2

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 53259588ethyl(E)-3-{2-[3-(1-adamantyl)-4-benzyloxyphenyl]-5-pyrazinyl}-2-propenoate

Product 1

HCID 136121078ethyl(E)-3-{2-[3-(1-adamantyl)-4-hydroxyphenyl]-5-pyrazinyl}-2-propenoateYield 94.5%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

A solution of ethyl(E)-3-{2-[3-(1-adamantyl)-4-benzyloxyphenyl]-5-pyrazinyl}-2-propenoate (477 mg, 0.96 mmol), 1.0 M boron tribromide (3.86 mmol) in CH2Cl2 (3.86 mL), and CH2Cl2 (13 mL) was stirred at −78° C. under argon for 2 h, quenched with water (50 mL), and extracted with EtOAc (100 mL, 50 mL, and 30 mL). The extracts were washed (brine) and dried. After solvent removal at reduced pressure, the residue was purified on silica gel (20% to 33% EtOAc/hexane) to give 367 mg (94%) of ethyl(E)-3-{2-[3-(1-adamantyl)-4-hydroxyphenyl]-5-pyrazinyl}-2-propenoate as a yellow solid, mp 212-215° C. IR 3352, 2843, 1686 cm−1; 1H NMR (CDCl3) δ 1.35 (t, J=7.3 Hz, 3H, OCH2CH3), 1.79 (bs, 6H, AdCH2), 2.10 (bs, 3H, AdCH), 2.18 (bs, 6H, AdCH2), 4.29 (q, J=7.3 Hz, 2H, OCH2CH3), 5.32 (s, 1H, OH), 6.77 (d, J=8.5 Hz, 1H, 5-ArH), 6.97 (d, J=15.9 Hz, 1H, CH═CHCO), 7.71 (d, J=15.9 Hz, 1H, CH═CHCO), 7.75 (dd, J=8.5 Hz, 2.4 Hz, 1H, 6-ArH), 7.98 (d, J=2.4 Hz, 1H, 2-ArH), 8.62 (d, J=1.2 Hz, 1H, 3-PyrH), 8.97 ppm (d, J=1.2 Hz, 1H, 6-PyrH). HRMS calcd C25H28N2O3 [M+H]+ 405.2173. found 405.2181.

Workup

  1. customquenched with water (50 mL)
  2. extractionextracted with EtOAc (100 mL, 50 mL, and 30 mL)
  3. washThe extracts were washed (brine)
  4. customdried
  5. customAfter solvent removal at reduced pressure
  6. customthe residue was purified on silica gel (20% to 33% EtOAc/hexane)

Sources & evidence

ORD record
ord-184f96858abb41008bcb1345532630c3
Source dataset
uspto-grants-2015_08
Patent number
US09096544B2

Reaction notes

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