Structure elucidation of an unprecedented alkaloid and a new limonoid from Xylocarpus granatum

An unprecedented new limonoid-based alkaloid, granatoine (1), and a new phragmalin, xylocarpin L (2), along with xyloccensin Y were isolated as minor components from the fruits of the Chinese mangrove plant Xylocarpus granatum. Their structures were elucidated by extensive spectroscopic data (1D and 2D NMR) analysis. A possible biogenetic pathway for granatoine was also depicted.     

Structure elucidation and synthesis of lycoposerramine-B, a novel oxime-containing Lycopodium alkaloid from Lycopodium serratum Thunb

A new alkaloid, lycoposerramine-B (1), containing an oxime function, was isolated from the club moss Lycopodium serratum Thunb. The structure of 1 was elucidated by spectroscopic analysis, including J-resolved HMBC spectroscopy, and confirmed by its synthesis from the known alkaloid, serratinine (3).     

Isolation, structure elucidation, and biological activity of a new alkaloid from Zanthoxylum rhetsa

Several biologically active alkaloids (1-4, 6), including a new quinazoline-6-carboxylic acid (1), were isolated from the medicinal plant Zanthoxylum rhetsa, an evergreen tree, native to subtropical areas. Whereas the pharmacological properties of the plant extract and single constituents have been widely tested, we now show that all of the metabolites have antialgal activities, all but 6 are antibacterial, and 6 and the reduction product 5 (derived from 4) are also antifungal.     

A short biomimetic synthesis of marine sponge alkaloid Pyrinadine A

The biomimetic synthesis of the marine sponge alkaloid Pyrinadine A, based on the oxidative dimerisation of hydroxylamine, is reported.     

A new flavonol glycoside from the flowers of Hosta plantaginea with cyclooxygenases-1/2 inhibitory and antioxidant activities

Hosta plantaginea was a traditional Chinese medicinal plants used to treat inflammatory and painful diseases with partial scientific validation. Solvent extractions followed by repeated chromatographic purification of the H. plantaginea flowers led to the isolation of one new flavonoid glycoside, hostaflavone A (1), together with one related known compound, kaempferol-3-O-sophoroside-7-O-glucoside (2), and their structures were elucidated on the basis of chemical and spectral evidence, as well as by comparison with literature data. Compounds 1 and 2 were evaluated for the anti-inflammatory activites against cyclooxygenases (COX-1 and COX-2) and DPPH free radical-scavenging activities in vitro. The results revealed that 1 and 2 exhibited significant COX-1 inhibition and moderate COX-2 inhibition compared to the reference celecoxib. Additionally, 1 and 2 displayed insignificant antioxidant activities compared to the positive control L-ascorbic acid.     

Structure of protoveratrine C,a new alkaloid from provoveratrine

Single-crystal $\text{X}$-ray analysis has established that provoveratrine C, a third tetraester component of proveratrine, is protoverine 3-(2′$\text{S}$,3′$\text{R}$-2′,3′-dihydroxy-2′-methylbutyrate 6,7-diacetate 15-(2′$\text{R}$)-methylbutyrate.     

First total synthesis of a new pyrrolizidine alkaloid, amphorogynine A

An efficient and stereodefined strategy is described for the first asymmetric synthesis of a new type of pyrrolizidine alkaloids, amphorogynine A and its 1-epi-isomer. The key 2,4-disubstituted pyrrolidine ring was constructed by elaboration of the chiral lactam derivative incorporating the d-malic acid-derived skeleton through asymmetric cis-allylation of the functionalized allysilane.     

Structural elucidation and NMR assignments of a new pyrrolizidine alkaloid from Crotalaria vitellina Ker Gawl

A new pyrrolizidine alkaloid, named crotavitelin, was isolated from fruits of Crotalaria vitellina, Fabaceae (Papilionoideae). The structure was established by spectroscopic techniques such as one‐dimensional and two‐dimensional NMR, IR, and MS. Copyright © 2013 John Wiley & Sons, Ltd.     

用核磁共振测定桂花中一个新的内酯化合物的结构

Lignans are widely distributed secondary metabolites in Oleaceae plant. They are also of rapidly growing interest because of their effect of anticancer. Oleaceae plants distribted in the whole China. There are serval epieudesmin-type lignan 1 to be isolated from Oleaceae plants. It is reported the lignan exbibits the activity of anticancer and antioxidant.     

Structure of paniculamine,a new alkaloid fromAconitum paniculatum

From the roots of the cultivated plant Aconitum paniculatum Lam. we have isolated a new diterpene alkaloid of the denudatine type, which we have called paniculamine and have established its structure by x-ray structural analysis (diffractometer, CuK= radiation, 1729 reflections, direct method, R = O. 055).Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 89 14 75. Translated from Khimiya Prirodnylh Soedinenii, No. 2, pp. 277–282, March-April, 1995. Original article submitted November 15, 1994.     

Structure and total synthesis of deplancheine,a novel indoloquinolizidine alkaloid

The structure of deplancheine $\text{5}$, an indoloquinolizidine alkaloid of a novel type, has been established from its spectral properties and also by an orginal synthesis.     

Structure of ipomine,a new alkaloid from Ipomoea muricata jacq

Studies on the basic fraction from Ipomoeamuricata Jacq. seeds, grown in Senegal, resulted in the isolation of two hexahydroindolizine alkaloids, the previously described ipalbidine and a new alkaloid, ipomine, C₃₀H₃₅NO₈, the structure of which is established as 1-β-ipalbidinyl-4-p-coumaroyl-d-glucopyranoside.     

Liphagal, a Selective inhibitor of PI3 kinase alpha isolated from the sponge akacoralliphaga: structure elucidation and biomimetic synthesis

[structure: see text] Liphagal (1), a selective inhibitor of PI3K alpha, has been isolated from the marine sponge Aka coralliphaga collected in Dominica. The "liphagane" meroterpenoid carbon skeleton of liphagal (1) is new. A biomimetic total synthesis has been used to confirm the constitution of liphagal (1) and support a proposed biogenesis.