Structures of Products and Reaction Pathways of Autoxidation of 1, 5Diisopropylazulene and 1, 1′-Methylenebis (3, 7-diisopropylazulene) in Polar Aprotic Solvents

Abstract

Autoxidation of 1, 5-diisopropylazulene C/A0 at 115°C in HMPA (or DMF) yielded 22separable products. All the compounds were monomeric and dimeric products containing an extra carbon unit ([1G], [1N], [1A₂], [1D₅], [1D₂]), naphthoquinone [1D₁], 1 H-inden-1-ones ([1D₄], [1H]), azulenylbenzofulvenes ([1B_1.2], [1C], [1D₈], [1F], [1L], [1M], [1O], [1R_1.0], and diazulenylbenzofulvenes ([1E], [1I], [1P], [1S]), structures of which were established on the basis of spectroscopic data (UV, MS, IR, and NMR). Similarly autoxidation of 1, 1′-methylenebis(3, 7-diisopropylazulene) [1A₂] at 115°C in HMPA (or DMF) gave 14separable products ([1G], [1N], [1D₅], [1D₂], [1B_1.2], [1C], [1D₃], [1F], [1L], [1M], [1O], [1R_1.2], which had been previously obtained by the autoxidation of [1A₁]. Possible re action pathways through radical reaction schemes are discussed for the formation of all the products.