Nitrogen → 5-Methyl-6-(2-methylpropenyl)nicotinic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of 6-chloro-5-methyl-nicotinic acid ethyl ester (4.98 g, 24.9 mmol), 2,4,6-tri-(2-methyl-propenyl)-cycloboroxane pyridine complex (5.74 g, 17.7 mmol, prepared in analogy to a procedure given by F. Kerins, D. F. O'Shea J. Org. Chem. 67 (2002) 4968-4971), and triphenylphosphine (1.15 g, 4.4 mmol) in DME (60 mL), a solution of 2 M aq. K2CO3 (20 mL) is added. The mixture is degassed and flushed with N2 before Pd(PPh3)4 (460 mg, 0.4 mmol) is added. The mixture is stirred at 90° C. for 20 h before it is cooled to rt, diluted with EA (150 mL) and washed with sat. aq. NaHCO3 (2×50 mL). The org. extract is dried over MgSO4, filtered and evaporated. The crude product is purified by FC (SiO2, heptane-EA) to give 5-methyl-6-(2-methyl-propenyl)-nicotinic acid ethyl ester (3.98 g) as an orange oil; LC-MS: tR=0.72 min, [M+1]+=220.15.

Provenance & Evidence