Benzoic acid, 4-(5-ethyl-1,2,4-oxadiazol-3-yl)- (9CI) synthesis

Yield: 86%

Reaction Conditions:

with basic cobalt(II) carbonate;sodium bromide in acetic acid at 95; for 11 h;Green chemistry;

Steps:

Oxidation of 4 and 3 methyl-5-R-1,2,4-oxadiazoles (general procedure).
General procedure: Oxidation process was carried out in an ideal mixing reactor. A starting methylarene 1a-h (13 mmol), cobalt acetate (1.3 mmol), and sodium bromide (1.3 mmol) were dissolved in glacial acetic acid (40 mL). Then, the solution was heated to 95 °C and air was fed to the reactor. The reaction mixture was allowed to stand for 11 h at 95 °C and cooled to ~20 °C, a precipitate formed was filtered.

References:

Krasouskaya;Danilova;Baikov;Kolobov;Kofanov [Russian Chemical Bulletin,2015,vol. 64,# 1,p. 142 - 145][Izv. Akad. Nauk, Ser. Khim.,2015,# 1,p. 142 - 145,4]