Oxidation of 2-alkyl furans containing oxyamino group in alkyl chains

The furan ring is an important building block of biologically active natural and synthetic products. In this study; the syntheses of alkyl furan derivatives containing hydroxylamine at C-1 and C-2 positions of the alkyl side chain was carried out. Optimal conditions were determined for photo- and chemo-oxidation for the oxidation of the furan ring. Hemiacetal 169 was obtained by oxidation and photooxidation (RB, TPP) of 167 with the hydroxylamine group at the C-2 position with m-CPBA. The oxidation of hemiacetal with Jones reagent resulted in β-lactone 173. With photooxidation and chemical oxidation used for the oxidation of 184, 185 was obtained as a diastereomeric mixture as a result of attack of the hydroxylamine to the carbonyl group at the C-4 position. 187 was synthesized by treatment of the resulting hemiacetal 185 with Jones reagent. The compound 193 was synthesized by the chemical oxidation (m-CPBA, NBS) and photooxidation (RB and TPP) of 190, followed by an intramolecular nucleophilic attack of the hydroxylamine to the aldehyde carbon to obtain the seven membered heterocyclic compound 192. 200 was synthesized which was able to be functionalized as a result of the oxidation of 192 with Jones reactivity. The heterocyclic 206 was obtained from the oxidation of 205 with m-CPBA and the hydroxyl group was oxidized to complete the synthesis of the 207 compound.