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

HRID 2201685Notes

Reaction equation

HRID 2201685 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-db55e1f2f4cb4fb69d87d452b8104580
Source dataset
uspto-grants-2016_06
Patent number
US09365498B2

Reaction notes

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