Preparation of 2,2-dimethylchroman-4-ones from 5-alkyl-substituted resorcinols: microwave-assisted synthesis and theoretical calculations

Abstract

The influence of different 5-alkyl-substituted resorcinols on the formation of 2,2-dimethylchroman-4-ones is examined experimentally and theoretically. Structures are fully assigned by means of experimental and theoretical 13 C and 1 H NMR chemical shifts. Based on experimental and theoretical calculations of Friedel-Crafts acylation, it is possible to explain the formation of 2,2-dimethyl-5-hydroxychroman-4-ones and/or 2,2-dimethyl-7-hydroxychroman-4-ones. Evaluation of their biological activity as cannabinoid receptor ligands is also reported.

Substituent Effects on NMR Spectroscopy of 2,2-Dimethylchroman-4-one Derivatives: Experimental and Theoretical Studies

“…Based on our previous work and after an accurate survey of the literature, we decided to collect the 1 H and 13 C NMR spectroscopic data of 2,2-dimethylchroman-4-one derivatives from Series 1-3 [30][31][32]. In turn, these values have been exploited to analyze the effect connected with the introduction of a given substituent onto the parent structure in terms of: i) Lynch correlations to evaluate the proportionality relationships with respect to the appropriate substituent chemical shift (SCS) in monosubstituted benzene; and ii) Hammett correlations to show the resonance and inductive transmission of substituent electronic effects.…”

“…Based on our previous work and after an accurate survey of the literature, we decided to collect the 1 H and 13 C NMR spectroscopic data of 2,2-dimethylchroman-4-one derivatives from Series 1-3 [30][31][32].…”

“…The synthesis and full characterization of the 2,2-dimethylchroman-4-one derivatives belonging to Series 1-3 have been reported in previous studies [30][31][32].…”