Some reactions of oximes and related topics

Abstract

The thesis entitled “Some Reactions of Oximes and Related Topics” is divided into four chapters.

Chapter I This chapter describes a new reaction of oximes wherein ?? and ??acetoxyenamides (2, 3) are obtained from ketoximes having two ??methylene groups by treating the latter with a mixture of acetyl chloride, acetic anhydride, and pyridine. A few chemical transformations of ??acetoxyenamides (3) have been discussed. The reaction has also been studied with a deuterated ketoxime.

Chapter II This chapter describes a new one?step conversion of ketoximes into ??acetyl ketones (4). When heated with a mixture of pyridine, acetyl chloride, and acetic anhydride, and then worked up with water, ketoximes afford ??acetoxyketones in 40–72% yield. (1) AcCl, Py?Ac2O(2) H2O??-acetoxyketone (4)\text{(1) AcCl, Py} \quad \xrightarrow{\text{Ac}_2\text{O}} \quad \text{(2) H}_2\text{O} \quad \Rightarrow \quad \alpha\text{-acetoxyketone (4)}(1) AcCl, PyAc2?O?(2) H2?O??-acetoxyketone (4)

Chapter III This chapter describes a new synthesis of 2?methyl?4,5?disubstituted oxazoles from ketoximes. Ketoximes are treated with a mixture of acetyl chloride, acetic anhydride, and pyridine at 100?°C, followed by dry HCl gas bubbled through the reaction mixture, to afford 2?methyl?4,5?disubstituted oxazoles (6). Ketoxime?(2) Dry HCl(1) AcCl, Py, Ac2O;?100?C??2?methyl?4,5?disubstituted oxazole (6)\text{Ketoxime} \xrightarrow[\text{(2) Dry HCl}]{\text{(1) AcCl, Py, Ac}_2\text{O};\,100^\circ\text{C}} \; \text{2?methyl?4,5?disubstituted oxazole (6)}Ketoxime(1) AcCl, Py, Ac2?O;100?C(2) Dry HCl?2?methyl?4,5?disubstituted oxazole (6) A convenient synthesis of 2,4,5?trisubstituted oxazoles from ketoximes is also discussed. Ketoximes, when heated with various acid chlorides, furnish 2,4,5?trisubstituted oxazoles (7). Ketoxime???100?C??RCOCl??2,4,5?trisubstituted oxazole (7)\text{Ketoxime} \xrightarrow[\;100^\circ\text{C}\;]{\text{RCOCl}} \; \text{2,4,5?trisubstituted oxazole (7)}KetoximeRCOCl100?C?2,4,5?trisubstituted oxazole (7)

Chapter IV This chapter describes cycloaddition reactions of benzyne with oxazoles. Two molecules of benzyne react with oxazoles to give 9,10?disubstituted anthracenes (8) in good yields.