Synthesis of a pyrrolidine derivative of a carvotacetone and monoterpenes for anti-methicillin-resistant Staphylococcus aureus and anti-cryptococcal properties

Monoterpene derivatives are of great biological relevance in the pharmaceutical industry. In the present study, pyrrolidine derivative of a carvotacetone, 3-O-benzylcarvotacetone (1), and selected monoterpenes (3-hydroxy-2-isopropyl-5-methyl-p-benzoquinone (3) and cis-piperitol (5)) were prepared to provide (R)-1-(4-(benzyloxy)-5-isopropyl-2-methylcyclohexa-1,3-dien-1-yl)-pyrrolidine (2), 2-isopropyl-5-methyl-3,6-dioxocyclohexa-1,4-dien-1-yl acetate (4), cis-3-hydroxypiperitone (6) and carvacrol (7). Structure of 2 was determined based on NMR and HRMS spectral data. Compound 4 exhibited activity against fungi Cryptococcus neoformans with an IC50 value of < 0.8 mu g/mL. In addition, this compound 4 had an IC50 value of 14.97 mu g/mL against methicillin resistant Staphylococcus aureus bacteria. Previous to the current study, both compound 6 and 7 had been reported to have anti-microbial and anti-fungal activities.