Nitrogen → HCID 58102348, compound

Participants

Reaction Conditions

Reaction Steps

3-Chloropyrazine-2-carbonitrile (3.0 g; 21.5 mmol) was dissolved in dimethoxyethane (65 ml) and 4-tolylboronic acid (3.2 g; 23.65 mmol) was added, followed by the addition of K2CO3 (8.2 g; 59 mmol) and water (30 ml). The reaction mixture was deoxygenized with N2 (g) for 3 minutes followed by the addition of triphenylphosphine (842 mg; 3.2 mmol) and palladium(II)acetate (237 mg; 1.06 mmol). The reaction mixture was heated to 90° C. for 14 h, cooled to rt, diluted with EtOAc, filtered over a plug of celite and dried with magnesiumsulfate. The organic solvent was evaporated under reduced pressure to give 5.3 g of 3-p-tolyl-pyrazine-2-carbonitrile. The intermediate nitrile was dissolved in MeOH (110 ml) followed by the addition of 4M aq NaOH (180 ml). The resulting mixture was heated to 85° C. for 14 h, cooled to rt and the MeOH was evaporated under reduced pressure. The residual aq. phase was acidified to pH=2 by the addition of conc. HCl and the precipitated product was filtered off, dissolved in DCM/EtOAc and dried over magnesium sulfate, filtered and concentrated under reduced pressure to give 2.30 g of 3-p-tolyl-pyrazine-2-carboxylic acid. LC-MS: tR=0.40 min; [M−H]+=213.14.

Provenance & Evidence