Two halosesquiterpenes from Laurencia composita

Abstract

aTwo new chamigrane sesquiterpenes, yicterpenes A (1) and B (2) each with an unprecedented halogenation at C-9 and a hemiketal unit at C-10, were isolated from the marine red alga Laurencia composita. The structures and absolute configurations of them were identified by NMR, ECD, and mass spectrometric methods as well as quantum chemical calculations. Compound 1 with a chlorination at C-9was more active against some tested marine-derived organisms than 2 with a bromination at C-9.

Sesquiterpenes from the Brazilian Red Alga Laurencia dendroidea J. Agardh

“…Ring B was proposed based on correlations between methylenes protons at δ H 2.81 (H-2a) and δ H 1.76 (H-1b) on the COSY spectrum along with HMBC correlations from δ H 2.46 (H-5b) to δ C 197.6 (C-4) and from δ H 1.76 (H-1b) to δ C 48.7 (C-6). Based on the 13 C-NMR data, a chlorine atom was assigned to C-15 [22]. The Z configuration of C-3 double bond was proposed from the observation of correlation between H 2 -2/H-15 on NOESY spectrum.…”

Marine natural products

“…The chamigrane sesquiterpenes yicterpene A 541 and B 542 were isolated from L. composita (Pingtan Is., China). 575 Of the 7 compounds isolated from L. similis (Sepanggar Is., Kota Kinabalu, Sabah), ent-1(10)-aristolen-9b-ol 543 was claimed as an enantiomer of a known compound. 576,577 Two bromophenols 544 and 545 with radical scavenging activity were obtained from Symphyocladia latiuscula (Qingdao, Shandong Province, China).…”

Zinc Oxide Based Composite Materials for Advanced Supercapacitors

“…[19] It is well known that the larger the rectangle of the CV curve, the higher the capacitance and conductivity of the electrode. [66][67][68][69][70] The experimental results revealed that the electrochemical properties were enhanced with the increase of heat treatment temperature. Figure 3(H) revealed that the Nyquist plots of the ACZ-2-600, ACZ-2-700 and ACZ-2-800 electrodes in the frequency range of 100 mHz À100 kHz.…”