1,8-Diazabicyclo(5.4.0)undec-7-ene → 4-Benzo[d]isoxazol-3-yl-piperazine-1-carboxylic acid tert-butyl ester

HRID 970141Notes

Reaction equation

HRID 970141 reaction equation
Cl[C:2]1[C:6]2[CH:7]=[CH:8][CH:9]=[CH:10][C:5]=2[O:4][N:3]=1.[C:11]([O:15][C:16]([N:18]1[CH2:23][CH2:22][NH:21][CH2:20][CH2:19]1)=[O:17])([CH3:14])([CH3:13])[CH3:12].C1CCN2C(=NCCC2)CC1>N1C=CC=CC=1>[C:11]([O:15][C:16]([N:18]1[CH2:23][CH2:22][N:21]([C:2]2[C:6]3[CH:7]=[CH:8][CH:9]=[CH:10][C:5]=3[O:4][N:3]=2)[CH2:20][CH2:19]1)=[O:17])([CH3:14])([CH3:12])[CH3:13]

Participants

5

Reactant 3

HCID 811841,8-Diazabicyclo(5.4.0)undec-7-eneHCID 143452tert-Butyl piperazine-1-carboxylateHCID 27797803-Chloro-1,2-benzoxazole

Product 1

HCID 592523164-Benzo[d]isoxazol-3-yl-piperazine-1-carboxylic acid tert-butyl esterYield 42%

Reagents, catalysts & solvents 1

HCID 1049PyridineSolvent

Conditions

Temperature
100 °C

Procedure

To a stirred solution of 100 mg (0.65 mmol) of 3-chloro-1,2-benzisoxazole in pyridine (1 mL) was added 145 mg of piperazine-1-carboxylic acid tert-butyl ester (0.78 mmol) and 0.18 mL of DBU (0.78 mmol). The mixture was stirred at 100° C. overnight and then partitioned between EtOAC (50 mL) and water (20 mL) and separated. The aqueous layer was extracted with EtOAC (2×30 mL). The combined organic layers were then washed with water (25 mL), brine, dried over Na2SO4, and the solvent was removed under reduced pressure to give crude product. Purification by column chromatography (silica, 60-100% CH2Cl2/hexanes) gave 82 mg (42%) of the desired product as a light yellow solid. MS (electrospray): exact mass calculated for C16H21N3O3, 303.16; m/z found, 326.1 [M+Na]+. 1H NMR (CDCl3, 400 MHz): 7.68 (dt, J=8.02, 0.98 Hz, 1H), 7.52-7.44 (m, 2H), 7.24 (ddd, J=8.42, 6.46, 1.57 Hz, 1H), 3.66-3.61 (m, 4H), 3.56-3.49 (m, 4H), 1.49 (s, 9H).

Workup

  1. custompartitioned between EtOAC (50 mL) and water (20 mL)
  2. customseparated
  3. extractionThe aqueous layer was extracted with EtOAC (2×30 mL)
  4. washThe combined organic layers were then washed with water (25 mL), brine
  5. dry with materialdried over Na2SO4
  6. customthe solvent was removed under reduced pressure
  7. customto give crude product
  8. customPurification by column chromatography (silica, 60-100% CH2Cl2/hexanes)

Sources & evidence

ORD record
ord-23e37499951545e6bf55cdbc5fb5a311
Source dataset
uspto-grants-2007_12
Patent number
US07309703B2

Reaction notes

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