Friedel-Craft acylation of ar-himachalene: synthesis of acyl-ar-himachalene and a new acyl-hydroperoxide

Catalytic β-Bromohydroxylation of Natural Terpenes: Useful Intermediates for the Synthesis of Terpenic Epoxides

In a one-step procedure, various β-bromoalcohols were synthesized from natural terpenes in good to excellent yields. Using different catalysts, the reaction was carried out at room temperature, with H2O as nucleophile and N-bromosuccinimide as a bromine source under mild reaction conditions. The synthesized β-bromoalcohols were subsequently converted in situ to the corresponding epoxides in good yields.

Synthesis of novel antimicrobial aryl himachalene derivatives from naturally occurring himachalenes

Five new 2,9,9-trimethyl-6,7,8,9-tetrahydro-benzocyclohepten-5-ylidene-amine derivatives (16a-16e) were synthesized from α-dehydro-ar-himachalene (11) that was originally prepared from an isomeric mixture of α, β and γ himachalenes (10), the abundant sesquiterpenes of Cedrus deodara essential oil. In addition, different aryl himachalenes derivatives (9, 12, 14 and 15) were also formed from 11. The structures of the synthesized compounds were confirmed on the basis of their NMR, IR and mass spectral data. The prepared compounds were tested against a group of sixteen organisms including gram positive and gram negative bacterial and fungal strains. The introduction of a series of substituted imine groups into aryl himachalenes at 5(th) position (16a-16e) enhanced antimicrobial activity as compared to the aromatized derivatives (9, 12, 14 and 15) against gram-positive bacteria Bacillus subtilis, Micrococcus luteus and Staphylococcus aureus, and mycotoxigenic fungi Aspergillus parasiticus, A. ochraceous and A. sydowii. graphical Abstract, Figure 1(Fig. 1).