Studies On The Nitration Of α,β Unsaturated Ketones And The Ring-opening Reaction Of Epoxy Ketones With Nitric Oxide

In this dissertation, I will represent my studies on the nitration of Chalcone derivatives, reaction of epoxide ketone, and the aromatization of 3,5-disubstitued 2-isoxazolines with nitric oxide (NO). The principal results are expressed as follows.1. The nitration of chalcone derivatives with NO occurred highly stereoselectively uniquely affording E-a-nitro-propenones in good yield. The reaction is most likely initiated by electrophilic addition of NO to the C-C double bond specifically at the a-position. It provides a new approach for preparing a-nitro chalcone derivatives directly from chalcone derivatives using NO. It has the advantage of high steroselectivity, available starting materials and convenient performance under mild conditions. Products can be used in the synthesis of heterocycle compounds.2. The ring-opening reaction of epoxy ketones with NO in dichloromethane affords the C-3 ring-opened products, erythro-a -hydroxyl nitrates, in a highly syn-selective manner. No reaction occurred when the system was absolutely protected from air. The reaction is assumed to be initiated by NO₂. When the reaction was performed in protonic solvent, such as methanol, an anti-methoxyl hydroxyl compound was obtained as the main product. It appeared that the reaction was controlled by solvent.3. 3, 5-disubstituted 2-isoxazolines were oxidized to corresponding isoxazoles by NO in dichloromethane. The reaction more likely occurred via a one-electron transfer process. This methord can be used for preparing 2-isoxazoles.