Two New Daphniphyllum Alkaloids from Daphniphyllum calycinum

Two new daphniphyllum alkaloids named 2‐hydroxyyunnandaphnine D ( 1 ) and methyl 7‐hydroxyhomodaphniphyllate ( 2 ), together with eight known alkaloids, daphnioldhanin D, calyciphylline F, calyciphylline B, deoxycalyciphylline B, daphnicyclidin H, macropodumine C, 9,10‐epoxycalycine A, and yunnandaphnine A, were isolated from the stems and leaves of Daphniphyllum calycinum. Their structures and relative configurations were established on the basis of spectral evidence (including 2D‐NMR) and subsequently confirmed by a single‐crystal X‐ray crystallographic diffraction analysis.     

A New Dimeric Alkaloid from the Leaf of Psychotria calocarpa

Psychotriasine was isolated from the leaves of Psychotria calocarpa (Rubiaceae). The structure was established by spectroscopic methods including 2D‐NMR analysis. To the best of our knowledge, psychotriasine is the first example of a dimeric tryptamine‐related alkaloid that contains a free N^α‐methyltryptamine unit in the molecule.     

Terpenoids from Roots of Chloranthus spicatus

Five new terpenoids, including four eudesmane‐type sesquiterpenoids, 1 – 4 , and one labdane‐type diterpenoid, 6 , together with ten known compounds, were isolated from the roots of Chloranthus spicatus. The structures and their relative configurations were mainly established by 1D‐ and 2D‐NMR spectra, and MS experiments.     

Trichocarpinine,a Novel Hetidine–Hetisine Type Bisditerpenoid Alkaloid from Aconitum tanguticum var. trichocarpum

Trichocarpinine ( 1 ), the first hetidine–hetisine type bisditerpenoid alkaloid, was isolated from the whole herbs of Aconitum tanguticum var. trichocarpum. Its structure was determined by a combination of spectroscopic techniques, including HR‐ESI‐MS and 1D‐ and 2D‐NMR experiments. Its plausible biogenetic pathway was proposed as well (Scheme).     

New Sesquiterpenes from the Flowers of Chrysanthemum indicum L.

Two new guaianolides (=guaianolactones), chrysanthguaianolactone A and B ( 1 and 2 , resp.), and one new eudesmane sesquiterpene, chrysanthemdiol A ( 6 ), together with seven known sesquiterpenes were isolated from the flowers of Chrysanthemum indicum L. Their structures were elucidated on the basis of spectroscopic evidence.     

Four New Alkaloids,Brevianamides O – R,from the Fungus Aspergillus versicolor

Four new alkaloids, brevianamides O–R ( 1 – 4 , resp.), were isolated from the AcOEt extract of the solid‐state fermented rice culture of the fungus Aspergillus versicolor. Their structures were elucidated on the basis of spectroscopic analyses.     

Two Novel Sesquiterpenoids from the Roots of Ferula ferulaeoides (Steud.) Korov.

Two new sesquiterpenoids, ferulactones A and B ( 1 and 2 , resp.), have been isolated from the roots of Ferula ferulaeoides (Steud.) Korov . Their structures and relative configurations were established by analysis of spectroscopic data. Their absolute configuration was assigned by application of the CD technique.     

A convergence of photo‐bergman cyclization and intramolecular chain collapse towards polymeric nanoparticles

Employing enediynes as crosslinking precursors, a novel yet efficient strategy, namely photo‐triggered Bergman cyclization, was integrated with intramolecular chain collapse to yield polymeric nanoparticles with the size regime below 20 nm. Enediyne motif was designed delicately to possess a high photo‐reactivity, with the double bond locked in a methyl benzoate ring while triple bonds substituted with phenyls. Single electron transfer‐living radical polymerization was conducted to provide linear acrylate copolymers with controlled molecular weights and narrow polydispersities. Poly(butylarylate‐co‐ 5 ) went through UV‐irradiation with a concurrent Bergman cyclization, resulting in well‐defined ultrafine polymeric nanoparticles. Results from NMR, Raman scattering, photoluminescence and UV‐vis spectra corroborated the presence of conjugative structures in the polymeric nanoparticles, indicating the occurrence of photo‐induced Bergman cyclization. A series of other acrylate‐based nanoparticles were investigated to confirm the applicability of such a unique strategy in thermal sensitive but UV‐stable polymeric structures, making photo‐Bergman cyclization a promising tool towards polymeric nanoparticles. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Chiral crystal of a C2v‐symmetric 1,3‐diazaaulene derivative showing efficient optical second harmonic generation

Achiral nonlinear optical (NLO) chromophores 1,3‐diazaazulene derivatives, 2‐(4′‐aminophenyl)‐6‐nitro‐1,3‐diazaazulene (APNA) and 2‐(4′‐N,N‐diphenylaminophenyl)‐6‐nitro‐1,3‐diazaazulene (DPAPNA), were synthesized with high yield. Despite the moderate static first hyperpolarizabilities (β₀) for both APNA [(136 ± 5) × 10^?30 esu] and DPAPNA [(263 ± 20) × 10^?30 esu], only APNA crystal shows a powder efficiency of second harmonic generation (SHG) of 23 times that of urea. It is shown that the APNA crystallization driven cooperatively by the strong H‐bonding network and the dipolar electrostatic interactions falls into the noncentrosymmetric P2₁2₁2₁ space group, and that the helical supramolecular assembly is solely responsible for the efficient SHG response. To the contrary, the DPAPNA crystal with centrosymmetric P‐1 space group is packed with antiparalleling dimmers, and is therefore completely SHG‐inactive. 1,3‐Diazaazulene derivatives are suggested to be potent building blocks for SHG‐active chiral crystals, which are advantageous in high thermal stability, excellent near‐infrared transparency and high degree of designing flexibility. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011