Potassium Carbonate → 4-Methyl-5-(2-methyl-propenyl)-pyridine-2-carboxylic acid ethyl ester

HRID 1908799Notes

Reaction equation

[CH2:1]([O:3][C:4]([C:6]1[CH:11]=[C:10]([CH3:12])[C:9](Br)=[CH:8][N:7]=1)=[O:5])[CH3:2].C([O-])([O-])=O.[K+].[K+]>COCCOC.C(OCC)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>[CH2:1]([O:3][C:4]([C:6]1[CH:11]=[C:10]([CH3:12])[C:9]([CH:9]=[C:10]([CH3:12])[CH3:11])=[CH:8][N:7]=1)=[O:5])[CH3:2]

Participants

Conditions

Temperature: 80 °C

Procedure

To a solution of 5-bromo-4-methyl-pyridine-2-carboxylic acid ethyl ester (4.03 g, 16.5 mmol) in DME (43 mL), 2,4,6-tri-(2-methyl-propenyl)-cycloboroxane pyridine complex (5.36 g, 16.5 mmol) followed by 2 N aq. K2CO3-solution (16 mL) is added. The mixture is degassed and put under argon before Pd(PPh3)4 (343 mg, 0.297 mmol) is added. The mixture is stirred at 80° C. for 6 h before it is cooled to rt, diluted with diethyl ether (50 mL), washed with sat. aq. NaHCO3-solution (3×30 mL), dried over MgSO4, filtered and concentrated. The crude product is purified by CC on silica gel eluting with heptane:EA 7:3 to give 4-methyl-5-(2-methyl-propenyl)-pyridine-2-carboxylic acid ethyl ester (1.33 g) as a yellow oil; LC-MS: tR=0.87 min, [M+1]+=220.08.

Workup

additionis added
customThe mixture is degassed
additionis added
temperatureis cooled to rt
washwashed with sat. aq. NaHCO3-solution (3×30 mL)
dry with materialdried over MgSO4
filtrationfiltered
concentrationconcentrated
customThe crude product is purified by CC on silica gel eluting with heptane:EA 7:3

Sources & evidence

ORD record: ord-cb2538c4b65f45a89a201419ee12f0cf
Source dataset: uspto-grants-2013_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08598208B2

Reaction notes

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