Ethyl chloroformate → 3-(2-Nitrophenyl)-1,2,4-oxadiazol-5(2H)-one

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Reaction Steps

The reactions of Equation 41 above can be run by methods known in the art. Thus, in reaction 41a, 2-nitrobenzamidoxime LII is reacted with ethyl chloroformate in excess pyridine at 0° to 100° C. for about 1 hour to form a 3-(2-nitrophenyl)-1,2,4-oxadiazolin-5-one of Formula (LIV), according to the teachings of A. R. Katritzky et al., Tetrahedron, 21, 1681 (1965). In reaction 41b, LIV is reacted with excess phosphorus oxychloride or phosphorus oxybromide with pyridine catalyst at 25° to 100° C. for 1 to 15 hours to form X1"', according to the teachings of T. Fujita et al., Yakugaku Zasshi, 84, 1061 (1964). And in reaction 41c, X1"' is reacted with sodium methoxide or sodium ethoxide in a solvent such as methanol, ethanol or tetrahydrofuran at 20° to 50° C. for about 0.2 to 1 hour to form X1"", according to the teachings of F. Eloy et al., Bull. Soc. Chim. Belg., 78, 47 (1969).

Provenance & Evidence