Li De-jiang
2005
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Journal
Fine chemicals
Abstract
Ethyl 4-nitrobenzoate (Ⅰ) was prepared in 81.1% yield by reaction of 4-nitrobenzoic acid with anhydrous ethanol in the presence of 98% sulfuric acid.I reacted with 80% hydrazine hydrate in of anhydrous ethanol as solvent at 100~105 ℃ for 8 h to give 4-nitrobenzoylhydrazine(Ⅱ) in 78.3% yield.In the presence of anhydrous ethanol at 85~90 ℃,Ⅱ reacted with benzaldehyde,4-chlorobenzaldehyde,2-chlorobenzaldehyde,2,4-dichlorobenzaldehyde,3-bromobenzaldehyde,4-methoxybenzaldehyde and acetophenone to produce the corresponding hydrazones (Ⅲa~g)in 93.2%,91.8%,90.1%,91.4%,88.1%,85.7% and 82.8% yield respectively.Then cyclodehydration of Ⅲa~g with acetic anhydide afforded 3-N-acetyl-2-aryl-5-(4-nitrophenyl)-1,3,4-oxadiazolines (Ⅳa~g)in 83.1%,85.6%,82.5%,79.5%,76.2%,73.1% and 70.8% yield respectively.Structures of Ⅳa~g were confirmed by elementary analysis,IR,~1HNMR,and MS spectroscopy.