Phenylglyoxal → 3-methyl-5-phenylpyrazin-2(1H)-one

Participants

Reaction Conditions

Reaction Steps

This compound was prepared following the procedure of Jones (J. Amer. Chem. Soc. 1949, 71, 78-81). Briefly, commercially available phenylglyoxal 22 (1.02 g, 7.62 mmol) was dissolved in methanol and cooled to 41° C. Commercially available alanine amide 23 (672 mg, 7.62 mmol) was dissolved in 25 ml methanol and added to the reaction mixture. A 12.5 N NaOH (0.760 mL, 9.53 mmol) solution was added dropwise while stirring, maintaining the temperature of the reaction below 40° C. When the addition was complete, the reaction was placed at =5° C. for 2 h. The reaction was then warmed to room temperature and quenched with 12 N HCl solution (0.76 mL), followed by sodium bicarbonate to neutralize the solution. The methanol was removed under reduced pressure, and the residue was extracted with chloroform and precipitated with ethyl acetate. The compound was isolated as a white powder to give 24 in 18% yield. HPLC (tr/purity): 1531 min, >97%. ESI m/z (MeOH): 187.35 (MH+).

Provenance & Evidence