Toluene → 3-Bromo-5-thiophen-3-yl-pyridine

HRID 23423Notes

Reaction equation

Br[C:2]1[CH:3]=[N:4][CH:5]=[C:6]([Br:8])[CH:7]=1.C1(C)C=CC=CC=1.[S:16]1[CH:20]=[CH:19][C:18](B(O)O)=[CH:17]1.C(=O)([O-])[O-].[Na+].[Na+]>O.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.C(O)C>[S:16]1[CH:20]=[CH:19][C:18]([C:2]2[CH:7]=[C:6]([Br:8])[CH:5]=[N:4][CH:3]=2)=[CH:17]1

Participants

Conditions

Temperature: 75 °C

Procedure

Under a nitrogen atmosphere, a mixture of 3,5-dibromopyridine (5 g, 21 mmol), distilled water (35 mL), toluene (140 mL), ethyl alcohol (35 mL), 3-thiopheneboronic acid (2.8 g, 22 mmol), sodium carbonate (4.67 g, 44.1 mmol) and tetrakis(triphenylphosphine)palladium (1.22 g, 1.05 mmol) were stirred. This black suspension was heated at 75° C. for 20 h. After cooling to room temperature, the mixture was diluted with distilled water (200 mL) and extracted with ethyl acetate (2×200 mL, then 100 mL). The combined organic phases were dried with MgSO4, filtered and concentrated by rotary evaporation, producing 17 g of a purple oil. Purification by column chromatography on silica gel, using cyclohexane:ethyl acetate (95:5) as eluent, afforded 2.9 g (58%) of white crystals, mp 58° C.

Workup

temperatureAfter cooling to room temperature
extractionextracted with ethyl acetate (2×200 mL
dry with materialThe combined organic phases were dried with MgSO4
filtrationfiltered
concentrationconcentrated by rotary evaporation

Sources & evidence

ORD record: ord-fdeba62057cb48a795feea56a6bba709
Source dataset: uspto-grants-2005_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06852721B2

Reaction notes

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