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ChemicalBook CAS DataBase List 2(1H)-Quinoxalinone, 5-methoxy-

2(1H)-Quinoxalinone, 5-methoxy- synthesis

3synthesis methods
-

Yield:-

Reaction Conditions:

Stage #1: 1,2-diamino-3-methoxybenzene dihydrochloridewith sodium hydrogencarbonate in ethanol;water;
Stage #2: glyoxylic acid ethyl ester in ethanol;water;toluene at 20; for 24 h;

Steps:

54.b

A solution of 3-methoxybenzene-1,2-diamine dihydrochloride from step (a) above (5.28 g, 25 mmol) in EtOH (30 mL) and H2O (70 mL) was neutralized by careful addition of solid NaHCO3. A solution of ethyl glyoxylate (50% in toluene, 5.45 mL, 27.5 mmol, Fluka) was added and the mixture was stirred at room temperature for 24 h. The mixture was diluted with sat aq. NH4Cl and extracted with 25% i-PrOH/CHCl3 (4×). The combined organic extracts were dried over Na2SO4, filtered and evaporated in vacuo. Purification of the residue by column chromatography (gradient: 0-2.5% 2M NH3 in MeOH/CH2Cl2) afforded 8-methoxy-1H-quinoxalin-2-one as an off-white powder [MS (ESI, pos. ion) m/z: 177 (M+1)] and 5-methoxy-1H-quinoxalin-2-one as an off-white powder [MS (ESI, pos. ion.) m/z: 177 (M+1)].

References:

US2005/176726,2005,A1 Location in patent:Page/Page column 28