title: Synthesis of novel antimicrobial aryl himachalene derivatives from naturally occurring himachalenes.
abstract: 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).
authors.affiliation: Natural Product Chemistry and Process Development Division, CSIR-Institute of Himalayan Bioresource Technology, P.O. Box 6, Palampur (H.P.)-176 061, India.
authors.forename: Abha
authors.initials: A
authors.lastname: Chaudhary
authors.affiliation: Plant Pathology and Microbiology Laboratory, Hill Area Tea Science Division, CSIR-Institute of Himalayan Bioresource Technology, P.O. Box 6, Palampur (H.P.)-176 061, India.
authors.forename: Swati
authors.initials: S
authors.lastname: Sood
authors.affiliation: Natural Product Chemistry and Process Development Division, CSIR-Institute of Himalayan Bioresource Technology, P.O. Box 6, Palampur (H.P.)-176 061, India.
authors.forename: Pralay
authors.initials: P
authors.lastname: Das
authors.affiliation: Natural Product Chemistry and Process Development Division, CSIR-Institute of Himalayan Bioresource Technology, P.O. Box 6, Palampur (H.P.)-176 061, India.
authors.forename: Pushpinder
authors.initials: P
authors.lastname: Kaur
authors.affiliation: Plant Pathology and Microbiology Laboratory, Hill Area Tea Science Division, CSIR-Institute of Himalayan Bioresource Technology, P.O. Box 6, Palampur (H.P.)-176 061, India.
authors.forename: Isha
authors.initials: I
authors.lastname: Mahajan
authors.affiliation: Plant Pathology and Microbiology Laboratory, Hill Area Tea Science Division, CSIR-Institute of Himalayan Bioresource Technology, P.O. Box 6, Palampur (H.P.)-176 061, India.
authors.forename: Arvind
authors.initials: A
authors.lastname: Gulati
authors.affiliation: Natural Product Chemistry and Process Development Division, CSIR-Institute of Himalayan Bioresource Technology, P.O. Box 6, Palampur (H.P.)-176 061, India.
authors.forename: Bikram
authors.initials: B
authors.lastname: Singh
keywords: Cedrus deodara; antimicrobial activity; essential oil; himachalenes