5-(2-nitrophenyl)-1,3,4-oxadiazolin-2-one

Sodium

methanol

methyl iodide

ethanol

hydrogen

Adams' catalyst (PtO₂.nH₂O) 10.1021/ja01427a021

5-(2-nitrophenyl)-1,3,4-oxadiazolin-2-one (2.07 g, 0.01 mole) was dissolved in a solution of sodium (0.4 g) in methanol (25 ml). Methyl iodide (2 ml) was added and the mixture was heated under reflux for 1h. The excess methyl iodide was distilled off [Water bath] and water was added to precipitate 3-methyl-5-(2-nitrophenyl)-1,3,4-oxadiazolin-2-one (1.4 g, 64%).  This compound (1.046 g, 0.005 mole) was then added to a mixture of ethanol (25 ml) and Adams' catalyst (50 mg) and stirred under hydrogen. After 80 min, when 94% of the theoretical volume of hydrogen had been absorbed, the mixture was heated till it started to boil, and the platinum catalyst filtered off.  On cooling, 0.49 g of 3-methyl-(2-aminophenyl)-1,3,4-oxadiazolin-2-one was obtained. Concentration of the filtrate afforded a further 0.28 g making a total yield of 80%.

This product was identical with one of the products obtained by the methylation of 5-(2-aminophenyl)-1,3,4-oxadiazolidin-2-one.

3-methyl-5-(2-nitrophenyl)-1,3,4-oxazolidin-2-one, colourless needles, mp 123-124°

Found: C 48.74%, H 3.33%, N 18.66% Calc. for C₉H₇N₃O₄   C 48.87%, H 3.19%, N 19.00%

3-methyl-5-(2-aminophenyl)-1,3,4-oxadiazolin-2-one, mp 167-168°

Found: C 56.26%, H 4.64%, N 21.84%.   C₉H₉N₃O₂ requires C 56.54%, H 4.74%, N  21.98%.

NMR (in pyridine-d5) δ 3.37 (3H,s,Me), δ 6.3 (2H,broad s,NH₂), δ 6.5 -7.6 (4H, m, aromatic)

Davidson, J. S., Monatshefte fur chemie., 1984, 115, 565-571
doi:10.1007/BF00799164

Davidson, J. S., Monatshefte fur chemie., 1988, 119, 1027-1029
doi:10.1007/BF00810111