ISSN 2348-1218 (print) International Journal of Interdisciplinary Research and Innovations ISSN 2348-1226 (online) Vol. 9, Issue 1, pp: (6-11), Month: January - March 2021, Available at: www.researchpublish.com
Reduction of resin immobilized aryldiazonium ions in solid phase by aqueous sodium borohydride – A simple synthesis of arylhydrazines Dr. Atul Prasad Sikdar1, Dr. Pankaj Kumar Ghosh2 1
Assistant Professor, 2Associate Professor 1,2
Department of Chemistry
1,2
Mangaldai College, Mangaldai, Darrang-784125 : Assam : India e-mail : atul.sikdar@gmail.com
Abstract: A series of arylhyrazines were successfully synthesized by reducing resin immobilized aryldiazonium ions with aqueous NaBH4 solution under biphasic condition at room temperature. The reduction is clean with simple work-up procedure. The products were identified by comparing their melting points with authentic samples. The characterization of compounds was also done by conversion to their hydrazone derivatives with benzophenone as standard carbonyl compound followed by representative spectral data analysis. Keywords: Aryldiazonium ions; Resin immobilization; Solid phase reduction; Arylhydrazine.
I. INTRODUCTION Diazonium salts were first discovered by Peter Griess [1, 2, 3]. He prepared a diazonium salt by the action of nitrous gas on picramide. The azo functional group is one of the most important functional groups in organic chemistry primarily because of its presence in azo dyes and in many free radical initiators. Development of azo chemistry and its application in the dye stuff industry was influenced significantly by the investigations of Schraube and Schmidt [4]. The azo dyes constitute the largest single class of dyes making up over half of the total number of synthetic colours of commercial importance. As far as synthetic utilities of aryl diazonium ions are concerned, one of the most important utility is their conversion into corresponding arylhydrazines, because the organic derivative of hydrazine is phenylhydrazine, the simplest of the arylhydrazines. It was first prepared [5] in 1875 by Fischer and later proved to be one of the most valuable reagents in organic chemistry. The most striking illustration of its importance is that before phenylhydrazine was known, the chemistry of the sugar group was to a large extent an unsolved problem because of the difficulty of preparing crystalline derivatives, but with the aid of phenylhydrazine, Fischer was able to obtain such derivatives and arrive at the characteristics of sugars. The preparation of phenylhydrazine was a consequence of Griess’s work on diazo compounds in 1869. It has been found that from benzenediazonium chloride and sodium or potasium sulphite, a compound could be obtained which is now known to be the alkali diazosulphonate, PhN=NSO 3K/Na and this was reduced by more sulphite. Fischer showed that the resulting compound was the salt of phenylhydrazinesulphonic acid, PhNHNHSO 3Na and on boiling with hydrochloric acid, it was hydrolyzed to phenylhydrazine and sulphuric acid. Thus all the more important methods of preparing the monoarylhydrazines consist in the reduction of a diazo compound, and since any primary aromatic amine can be diazotized, hydrazines containing various substituted aryl groups can be readily obtained. The reduction can be carried out in several ways. Certain diazo compounds, such as that derived from p-nitroaniline, give a hydrazine disulphonate, and not a monosulphonate, but these are hydrolyzed to the hydrazine so that the method of
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