3,4-Dibromo-2-nitrothiophene → 2-(4-Bromo-2-nitrothiophen-3-yl)oxazole

HRID 1519936Notes

Reaction equation

Br[C:2]1[C:6]([Br:7])=[CH:5][S:4][C:3]=1[N+:8]([O-:10])=[O:9].C([Sn](CCCC)(CCCC)[C:16]1[O:17][CH:18]=[CH:19][N:20]=1)CCC>CN(C=O)C.C1C=CC([P]([Pd]([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)[P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1>[Br:7][C:6]1[C:2]([C:16]2[O:17][CH:18]=[CH:19][N:20]=2)=[C:3]([N+:8]([O-:10])=[O:9])[S:4][CH:5]=1

Participants

Conditions

Temperature: 90 °C

Procedure

A mixture of 3,4-dibromo-2-nitrothiophene (0.166 mg, 0.581 mmol), Pd(PPh3)4 (67 mg, 0.0581 mmol) and 2-(tributylstannyl)oxazole (250 mg, 0.698 mmol) in DMF (1.1 mL) was evacuated and purged with nitrogen three times. The reaction mixture was heated to 90° C. for 18 h and the resulting solution was cooled to room temperature and diluted with Et2O. The solution was washed with brine and the organic phase was separated, dried (Na2SO4), filtered, concentrated under vacuum and purified on a silica gel column (eluant hexane/ethyl acetate, 20/1 to 1/1, v/v) to give 2-(4-bromo-2-nitrothiophen-3-yl)oxazole (107 mg, 67%). Retention time (min)=1.948, method [1], MS(ESI) 274.9 (M+H).

Workup

customwas evacuated
custompurged with nitrogen three times
temperaturethe resulting solution was cooled to room temperature
additiondiluted with Et2O
washThe solution was washed with brine
customthe organic phase was separated
dry with materialdried (Na2SO4)
filtrationfiltered
concentrationconcentrated under vacuum
custompurified on a silica gel column (eluant hexane/ethyl acetate, 20/1 to 1/1

Sources & evidence

ORD record: ord-60af20f14a4d4b0f9e0edaaa253db1ac
Source dataset: uspto-grants-2015_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09073891B2

Reaction notes

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