Convenient Synthesis of 2,2′- and 4,4′-Methylenebisphenols with Bulky Alkyl Substituents and Evaluation of Their Antioxidant Activity

Abstract

The work is devoted to a convenient procedure of the synthesis of 2,2′- and 4,4′-methylenebisphenols with alkyl substituents in heterogeneous catalysis. This compounds were obtained with yields up to 87% by reflux of 2,4- or 2,6-dialkylphenols with HCHO in n-octane in the presence of KSF clay. We found that the antioxidant activity on DPPH test for two novel methylenebisphenols having isobornyl fragments was comparable with control drugs.

GRAPHICAL ABSTRACT

Keywords:

• Antioxidant activity
• heterogeneous catalysis
• methylenebisphenols

ACKNOWLEDGMENTS

This work was performed with the support of the Russian Academy of Sciences (fundamental research of the Presidium of the RAS “Biomedical and Biomolecular Chemistry” (Project No. 09-T-3-1023). The authors are grateful to Elena N. Zainullina for registration of NMR spectra.

Notes

^a Isolated yield after column chromatography on SiO₂ (without conversion).

^b Yield of compound 2b after synthesis in n-heptane is shown in brackets.

^c Product of reaction is a mixture of two diastereomers.

^d Product of reaction is a single meso-diastereomer.

^e Paraformaldehyde was also added portionwise every 1.5 h (1.47 mmol per serving).

^a Compound 2f was not used in AOA test because of a low solubility of sample in EtOH.

^b Used as mixtures of diastereomers meso-/rac-, 1:1.