3-Pyridinylboronic acid → HCID 68615877, compound

Participants

Reaction Steps

A mixture of 4-bromo-1-tert-butoxycarbonyl-2-(3,4,5-trimethoxyphenyl)-pyrrole (2.0 g, 5.0 mmol, Example 76b), Pd(PPh3)4 (290 mg, 0.25 mmol) and pyridine-3-boronic acid (614 mg, 5.0 mmol) are evacuated for 10 min and set under argon atmosphere, followed by addition of degassed dimethoxyethane (DME, 10 ml) and 2 M aqueous Na2CO3 solution (10 ml). The reaction mixture is heated for 20 h to 80° C., cooled to room temperature and diluted with water and ethyl acetate. The organic layer is dried (MgSO4), filtered and the solvents are evaporated. The residue is chromatographed with ethyl acetate/hexane (1:1) to yield first 1-tert-butoxycarbonyl-4-(3-pyridyl)-2-(3,4,5-trimethoxy-phenyl)-pyrrole (280 mg, 12%) as a yellowish amorphous solid and then the title compound (700 mg, 45%) as a yellowish solid, 1H-NMR (300 MHz, DMSO-d6): 11.52 (br.s, 1H); 7.88 (br. s, 1H); 8.33 (br.d; J=6.0, 1H); 8.0-7.95 (m, 1H); 7.48 (br.s, 1H); 7.35-7.3 (m, 1H); 7.07 (br.s, 1H); 7.02 (s, 2H); 3.85 (s, 2MeO); 3.67 (s, MeO).

Provenance & Evidence