PROCESS FOR THE PREPARATION OF OXADIAZOLINE DERIVATIVES

摘要

1416289 Process for 3-phenyl oxadiazoline derivatives RHONE-POULENC SA 20 March 1974 [22 March 1973] 12458/74 Heading C2C Oxadiazoline derivatives of general formula where R is a C 1-4 straight or branched alkyl radical, are obtained by reducing the nitro group in a compound of general formula to a hydroxylamino group by methods known per se which do not affect the rest of the molecule and converting this novel product of general formula by means of the Bamberger rearrangement to an aminophenol of general formula and converting the latter by methods known per se to the desired product without affecting the rest of the molecule. The reduction step is preferably effected with hydrogen in the presence of a Pd on carbon catalyst at 15-25‹ C. at atmospheric pressure. The Bamberger rearrangement may be performed by treatment with a strong inorganic acid such as H 2 SO 4 at a temperature below 25‹ C. The conversion of the amino phenol of Formula IV into product of Formula I is preferably achieved via the corresponding diazonium salt. The compounds of Formula I may be converted to compounds of formula by reacting with an alkyl halide of formula R1 1 X where R1 1 is C 1-4 alkyl. 5 - (t - Butyl)- and 5 - isopropyl - 3 - (2 - nitro- 4 - chlorophenyl) - 1,3,4 - oxadiazolin - 2 - one are produced by condensing 2,5-dichloronitrobenzene with 5-(t-butyl)- or 5-isopropyl-1,3,4- oxadiazolin-2-one respectively.