Ethyl chloroformate → Tert-butyl ethyl (4-(thiophen-2-yl)-1,2-phenylene)dicarbamate

HRID 62678Notes

Reaction equation

HRID 62678 reaction equation
[NH2:1][C:2]1[CH:7]=[C:6]([C:8]2[S:9][CH:10]=[CH:11][CH:12]=2)[CH:5]=[CH:4][C:3]=1[NH:13][C:14](=[O:20])[O:15][C:16]([CH3:19])([CH3:18])[CH3:17].Cl[C:22]([O:24][CH2:25][CH3:26])=[O:23]>ClCCl.CN(C1C=CN=CC=1)C.O>[S:9]1[CH:10]=[CH:11][CH:12]=[C:8]1[C:6]1[CH:5]=[CH:4][C:3]([NH:13][C:14](=[O:20])[O:15][C:16]([CH3:17])([CH3:19])[CH3:18])=[C:2]([NH:1][C:22](=[O:23])[O:24][CH2:25][CH3:26])[CH:7]=1

Participants

6

Reactant 2

HCID 10928Ethyl chloroformateHCID 57717474tert-Butyl (2-amino-4-(thiophen-2-yl)phenyl)carbamate

Product 1

HCID 71007309Tert-butyl ethyl (4-(thiophen-2-yl)-1,2-phenylene)dicarbamateYield 44%

Reagents, catalysts & solvents 3

HCID 142844-(Dimethylamino)pyridineCatalystHCID 962WaterSolventHCID 6344DichloromethaneSolvent2×

Procedure

To a solution of tert-butyl (2-amino-4-(thiophen-2-yl)phenyl)carbamate (0.20 g, 0.69 mmol, 1.0 equiv.) in dichloromethane (4 mL) was added ethyl chloroformate (0.08 mL, 0.83 mmol, 1.2 equiv.), TEA (0.19 mL, 1.37 mmol, 2.0 equiv.) and DMAP (8 mg, 0.07 mmol, 0.1 equiv.) at 0° C. The reaction was warmed to room temperature and stirred for 16 h. The reaction was then diluted with dichloromethane and water. The organic layer was separated, washed with water and brine, dried over sodium sulfate, filtered and concentrated under reduced pressure. The crude material was purified on column chromatography (silica gel, 20% EtOAc/hexanes) to give tert-butyl ethyl (4-(thiophen-2-yl)-1,2-phenylene)dicarbamate (0.11 g, 44% yield).

Workup

  1. customThe organic layer was separated
  2. washwashed with water and brine
  3. dry with materialdried over sodium sulfate
  4. filtrationfiltered
  5. concentrationconcentrated under reduced pressure
  6. customThe crude material was purified on column chromatography (silica gel, 20% EtOAc/hexanes)

Sources & evidence

ORD record
ord-9d1e233295fc4eff9d5a1d8a5e5b8cc4
Source dataset
uspto-grants-2016_09
Patent number
US09447030B2

Reaction notes

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