P(Cl)(Cl)(Cl)=O.[CH3:6][C:7]1[N:11]=[C:10]([CH2:12][C:13]([OH:15])=[O:14])[O:9][N:8]=1.[CH2:16](O)[C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1.CCCCCC>C1(C)C=CC=CC=1.C(OCC)C.C1(C)C=CC=CC=1.C1(C)C=CC=CC=1.CCCCCC>[CH3:6][C:7]1[N:11]=[C:10]([CH2:12][C:13]([O:15][CH2:16][C:17]2[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=2)=[O:14])[O:9][N:8]=1
Using the procedure of Example 17, 8 g of phosphorous oxychloride were slowly added to a mixture of 8 g of 3-methyl-1,2,4-oxadiazol-5-yl-acetic acid and 6.2 g of dry benzyl alcohol with the rate of addition adjusted to a reaction temperature of 40°-45° C. The resulting reaction mixture was stirred for 5 hours at 40° C. and then was treated in the usual manner. The obtained yellow oil was submitted to column chromatography over silica employing as eluents n-hexane and 3:1 hexane-toluene-, 1:1-toluene-hexane, 3:1 toluene-hexane mixture, toluene and finally a 3:1 toluene-diethyl ether mixture. The finally obtained colorless oil was 6.1 g (47% yield) of benzyl 3-methyl-1,2,4-oxadiazol-5-yl-acetate with a purity of about 95% (according to TLC and PMR spectrum) and a refractive index nD25 =1.518.
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