Pyridine → HCID 135964220, compound

Participants

Reaction Steps

To a solution of isonicotinic acid 4 (150 mg, 0.744 mmol), 4-benzyloxy-3,5-dimethyl-benzoic acid hydrazide (200 mg, 0.740 mmol) and DIPEA (302 mg, 2.34 mmol) in DCM (15 mL) PyBOP (420 mg, 0.807 mmol) is added portionwise at 0° C. The mixture is stirred at 0° C. for 3 h before pyridine (295 mg, 3.73 mmol) followed by trifluoromethanosulfonic acid anhydride (214 mg, 1.17 mmol) is added. The mixture is stirred at rt for 15 h before another portion of pyridine (295 mg, 3.73 mmol) and trifluoromethanosulfonic acid anhydride (214 mg, 1.17 mmol) is added. After stirring for 2 h yet another portion of pyridine (295 mg, 3.73 mmol) and trifluoromethanosulfonic acid anhydride (214 mg, 1.17 mmol) is added and stirring is continued for 2 h. Dimethylaminopropylamine (0.25 mL) is added and the mixture is stirred for 30 min before it is diluted with ether (100 mL), washed with 1 M aq. NaH2PO4 solution (2×30 mL) and sat. aq. Na2CO3 solution. The washings are extracted back with EA (2×75 mL). The combined org. extracts are dried over MgSO4, filtered and evaporated to give crude 4-[5-(4-benzyloxy-3,5-dimethyl-phenyl)-[1,3,4]oxadiazol-2-yl]-2-ethyl-6-methyl-pyridine; LC-MS: tR=1.12 min; [M+1]+=400.22. To a solution of this material in formic acid (0.125 mL), MeOH (5 mL) and THF (10 mL), Pd/C (50 mg, 10% Pd) is added and the mixture is stirred at rt under 1 bar of H2 for 15 h. The catalyst is removed by filtration and the solvent of the filtrate is evaporated. The residue is dissolved in EA (100 mL), washed with sat. aq. NaHCO3 solution, dried over MgSO4, filtered and concentrated. The crude product is purified by CC on silica gel eluting with EA to give 4-[5-(2-ethyl-6-methyl-pyridin-4-yl)-[1,3,4]oxadiazol-2-yl]-2,6-dimethyl-phenol (209 mg) as a beige foam; LC-MS: tR=0.74 min; [M+1]+=310.11.

Provenance & Evidence