PREPARATION OF ALPHA-NITROARYLIDENE AND ALPHA-NITROALKYLIDENE PHENYLHYDRAZINES BY THE ALKYL NITRATE NITRATION

LAWRENCE FRANCIS SPINICELLI, Purdue University

Abstract

The scope and utility of the alkyl nitrate nitration has been advanced by the successful application of the reaction to the preparation of (alpha)-nitroarylidene and (alpha)-nitroalkylidene phenylhydrazines from the parent arylidene and alkylidene phenylhydrazines. The generality of the reaction was realized by the preparation of a variety of (alpha)-nitro compounds from the phenylhydrazine derivatives of benzaldehyde, several substituted benzaldehydes, methanal, ethanal, butanal, 1-naphthaldehyde, 2-naphthaldehyde, 3-picolinaldehyde, furfural, and 2-thiophene carboxaldehyde. The procedure involved the addition of the arylidene or alkylidene phenylhydrazine to a freshly prepared suspension of potassium amide in liquid ammonia. Addition of a primary alkyl nitrate, such as n-propyl nitrate followed by isolation of the crude nitronate salt and aqueous acidification with acetic acid afforded the (alpha)-nitroarylidene or (alpha)-nitroalkylidene phenylhydrazine. Previous methods for the preparation of these nitro compounds involved the oxidation of arylazoaldoximes and the coupling of nitronate salts with diazonium compounds. However, the former method suffers from low yields and the latter is limited to the availability of primary nitroalkane derivatives. On the other hand, the alkyl nitrate nitration offers a great advantage over these methods because it is essentially a one-step reaction and usually affords the nitro compounds in high yield from readily available starting materials. The optimum yield of nitro compounds was obtained by employing 1.00 equimolar amount of potassium amide in 300 ml of ammonia and 2.00 equimolar amounts of n-propyl nitrate per equimolar amount of starting material. The times of anion formation and nitration were 0.75 and 0.50 hours, respectively. It was found that the yields of some nitro compounds could be increased significantly by performing the nitration in a more concentrated potassium amide-liquid ammonia solution. The ambident character of the anions of arylidene and alkylidene phenylhydrazines could give rise to either C-nitrated or N-nitrated products. In the course of this study, only C-nitrated products have been obtained. On the other hand, alkylations and acylations performed on arylidene and alkylidene phenylhydrazines in the potassium amide-liquid ammonia system gave only N-alkylated and N-acylated products in high yields. . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of school.) UMI

Degree

Ph.D.

Subject Area

Organic chemistry

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