Monoterpenoids from Acanthopanax sessiliflorus Fruits
Three new acyclic monoterpenoids named (2E)-3,7-dimethylocta-2,6-dienoate-6-O-α-l-arabinopyranosyl-(1→6)-β-d-glucopyranoside (1), (3Z,6E)-3,7-dimethyl-3,6-octadiene-1,2,8-triol (2) and (6E)-7-methyl-3-methylene-6-octene-1,2,8-triol (3) were isolated from Acanthopanax sessiliflorus fruits, along with three known monoterpenoid compounds. The structures of the new compounds were determined by means of extensive spectroscopic analysis (1D, 2D NMR and HRESIMS) and chemical methods.
Characterization and bioactive potentials of secondary metabolites from mollusks Crassostrea madrasensis and Amphioctopus marginatus
Abstract Chemical investigations of the ethyl acetate-methanol (EtOAc-MeOH) extract of the selected mollusks from the south-west coast of Arabian Sea led to the isolation of methyl-3-(26-phenylacetyloxy)-icosahydro-19-hydroxy-4,4,20-trimethylpicene-23-carboxylate (1) and methyl-3-(26-phenylacetyloxy)-icosahydro-1,19-dihydroxy-4,4,20-trimethylpicene-23-carboxylate (2) from Crassostrea madrasensis, whereas cholesta-5-en-3β-yl-(32-methyl-(30-((E)-34-amino-36-ethyl-39-oxohept-36-enyl)-pentanedioate (3) and 7-ethyl-9-vinyl-octahydroazuleno [1,8-bc]pyran-3,12-dione (4) were isolated from Amphioctopus marginatus. Their structures were assigned by detailed spectroscopic experiments. The studied compounds were checked for antioxidant and anti-inflammatory activities by various in vitro experiments. The radical quenching potential of 2,2-diphenyl-1-picrylhydrazyl and 2,2’-azino-bis-3-ethylbenzothiozoline-6-sulfonic acid diammonium salt were greater for 2 (IC50 0.85 and 1.10 mg/mL, respectively) than other studied compounds. The pro-inflammatory cyclooxygenase-2 inhibitory activity of 2 was greater (IC50 0.95 mg/mL) than those displayed by other studied compounds (>1.0 mg/mL). The 5-lipoxygenase inhibitory potential of 1 and 2 (~1.36 mg/mL) were greater than those displayed by 3 (1.64 mg/mL) and 4 (1.45 mg/mL).
Highly enantio- and diastereoselective synthesis of β-methyl-γ-monofluoromethyl-substituted alcohols.
Enanatiopure β-methyl-γ-monofluoromethyl alcohols were prepared from the allylic alkylation between fluorobis(phenylsulfonyl)methane with Morita-Baylis-Hillman carbonates. The reaction was catalyzed by using the Cinchona alkaloid derivative, (DHQD)(2)AQN. The origin of the stereoselectivity was verified by DFT methods. Calculated geometries and relative energies of various transition states strongly support the observed stereoselectivity.