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81.
Pattama Pittayakhajonwut Atit Usuwan Chakapong Intaraudom Punsa Khoyaiklang Sumalee Supothina 《Tetrahedron》2009,65(31):6069-789
Investigation of the insect pathogenic fungus Torrubiella luteorostrata led to the isolation of three new macrocyclic torrubiellutins A-C (1-3) and the known pyrone diterpene 4. Structures were elucidated by spectroscopic data including 1D, 2D NMR, and MS spectral data. The absolute stereochemistry was determined by chemical means using Mosher reactions and Marfey's reagent, together with NOESY spectral data. Torrubiellutin C showed biological activities against KB, MCF-7, NCI-H187, and Vero cell lines with IC50 varying from 0.78 to 4.36 μg/mL, while compound 4 exhibited antimalaria and anti-inflammatory activity with IC50 values of 3.49 and 1.21 μg/mL, respectively. 相似文献
82.
Five daphnane type diterpenes have been isolated from the chloroform soluble fraction of Daphne genkwa. The structure of the new compound (1) was assigned as 5beta-hydroxyresiniferonol-6alpha,7alpha-epoxy-12beta-acetoxy-9,13,14-ortho-2E-decenoate by extensive NMR studies. 相似文献
83.
The detailed investigation of the acetone extract from the wood of Juniperus formosana Hayata gave a new diterpene aldehyde which was elucidate as suginal on the basis of chemical and spectroscopic evidence. 相似文献
84.
二萜生物碱的~(13)C核磁共振谱 总被引:2,自引:0,他引:2
本文通过对186个二萜生物碱及其衍生物的~(13)C NMR谱数据的分析比较,就以下几方面作了归纳总结:①信号归属的方法;②常见取代基OCH_3、NCH_3、、NCH_2CH_3、OCOCH_3、的化学位移范围;③季碳和某些特定碳的化学位移规律。某些特定结构,如C_(20)二萜生物碱中的噁唑烷环以及C_(20)差向异构体等的~(13)C NMR谱特征;④C_(19)二萜生物碱中不同位置上取代基(H→OH、H→OMe、OH→OAc、OH→OMe、OH→C=O)效应和立体化学效应。这些归纳总结有助于此类化合物结构的阐明。 相似文献
85.
Andreas Luxenburger 《Tetrahedron》2003,59(32):6045-6049
In this paper we report on the development of a flexible and efficient synthetic approach towards 6,7-didehydrocarnosoic acid type analogues. The elaboration of the required trans-decalin system, the installation of the carboxylic acid in the angular position as well as the generation of the C6-C7 double bond to afford the 6,7-didehydrocarnosoic acid scaffold as it was found in 2 and 3 is described. 相似文献
86.
Panpan Zhang Shang Xue Pengfei Tang Zhirong Cui Zefan Wang Jun Luo Lingyi Kong 《中国化学快报》2021,32(4):1480-1484
Aphamines A–C (1–3), three pairs of acyclic diterpene dimer enantiomers with an unprecedent ploymerization pattern, were discovered from Aphanamixis polystachya by NMR-guided isolation and chiral resolution. The elucidation of their novel carbon skeletons was achieved based on spectroscopic analysis, exciton chirality, and calculated electronic circular dichroism (ECD). Plausible Claisen rearrangement, 5-exo-trig cyclization, and reduction reactions may play important roles in the polymeric biosynthesis pathway. Compounds 1 and 3 showed inhibitory effects on nitric oxide (NO) production (IC50: 6.71–15.36 μmol/L) and reduced the expression of iNOS in LPS-induced RAW 264.7 macrophages. 相似文献
87.
Sherif S. Ebada Aya N. Talaat Rola M. Labib Attila Mándi Tibor Kurtán Werner E.G. Müller AbdelNasser Singab Peter Proksch 《Tetrahedron》2017,73(21):3048-3055
Chemical investigation of a methanolic extract of leaves from Araucaria bidwillii (Araucariaceae) from Egypt afforded four new labdane diterpenoidal metabolites (1–4) together with one known diterpene, 7-oxocallitrisic acid (5), two triterpenoidal metabolites, 2-O-acetyl-11-keto-boswellic acid (6) and β-sitosterol-3-O-glucopyranoside (7), phloretic acid (8), and two methylated bisflavonoids, agathisflavone-4′,7,7″-trimethyl ether (9) and cupressuflavone-4′,7,7″-trimethyl ether (10). The new metabolites 1–4 were unambiguously identified by applying extensive 1D and 2D NMR spectroscopic studies as well as HRESIMS. The relative and absolute configurations of 1–4 were determined using ROESY and the modified Mosher's method, respectively. All isolated compounds were assessed for their antimicrobial, antitubercular and cytotoxic activities. Among the tested compounds, the new labdane diterpenes 1–4 revealed significant cytotoxic activity against mouse lymphoma L5178Y cell line with IC50 values ranging from 1.4 to 12.9 μM, respectively. 相似文献
88.
Tan Phat Nguyen Thi Thao Vy Tran Dinh Tri Mai Tien Dung Le Nhat Minh Phan Trong Dat Bui 《Natural product research》2015,29(15):1432-1436
From the leaves of Schefflera sessiliflora De P. V., one new C20-gibberellin diterpene 2β,12β-dihydroxygibberellin (12β-hydroxy-GA110 or 2β-hydroxy-GA112) (1), together with three known compounds, trans-tiliroside (2), kaempferol 3-O-β-d-glucuronopyranoside (3), 5-p-trans-coumaroylquinic acid (4), was isolated for the first time from the genus Schefflera by various chromatography methods. Their structures were elucidated by IR, UV, HR-ESI-MS, NMR 1D and 2D experiments and comparison with previous reported data. The α-glucosidase inhibitory activity of all compounds was measured. The isolates (2, 3) showed better α-glucosidase inhibitory activity (IC50 = 134.60, 147.10 μM, respectively) than the standard drug acarbose (IC50 = 214.50 μM). 相似文献
89.
90.
迷迭香单体的抗氧化活性 总被引:3,自引:0,他引:3
采用柱层析方法对迷迭香抗氧化剂(Rao)进行分离,分离出8个含量较高的单体.用光度法、ESR法、滴定法测定了迷迭香的8个单体、单体组合及Rao的抗氧化活性,并分析了抗氧化活性与其结构的关系.结果表明,在单体中,对超氧阴离子自由基及羟基自由基清除率最高的是槲皮素,分别为82.6%和87.1%.对香烟烟气自由基平均清除率最高的是迷迭香二酚,清除率为48.17%.单体活性最强的槲皮素和迷迭香二酚组合后,其抗氧化活性高于单体.活性强的抗氧化剂对油脂过氧化的抑制效果好,但作用时间较短. 相似文献