Structure determination of germacrane-type sesquiterpene alcohols from an endophyte Streptomyces griseus subsp

Three germacrane-type sesquiterpene alcohols were isolated from an endophyte of mangrove plant Kandelia candel. Their structures were characterized as 1(10)E,5E-germacradiene-11-ol (1), 1(10)E,5E-germacradiene-3,11-diol (2), 1(10)E,5E-germacradiene-2,11-diol (3) based on the extensive NMR studies. Among them, 2 and 3 are identified as new compounds.     

Structural determination of three new germacrane-type sesquiterpene alcohols from curdione by microbial transformation

Five germacrane-type sesquiterpene alcohols obtained from curdione (1) by microbial biotransformation were isolated. Their structures were characterized as (2R)-2beta-hydroxycurdione (2), 1alpha, 10beta-epoxy-11-hydroxycurdione (3), (2S)-2alpha, 11-dihydroxycurdione (4), 11,15-dihydroxycurdione (5) and (3R)-3alpha-hydroxycurdione (6) based on the extensive NMR studies. Among them, 4, 5 and 6 are new compounds.     

The brasilenols,rearranged sesquiterpene alcohols isolated from the marine opisthobranch aplysia brasiliana

Two nonisoprenoid sesquiterpene alcohols, brasilenol and epibrasilenol, have been isolated, along with brasilenol acetate, from the digestive glands of the marine opisthobranch Aplysia brasiliana. The structures of these unusual sesquiterpenoids were determined by extensive spectral and chemical analysis and by their mutual conversion to the corresponding α,β-unsaturated ketone, brasilenone. The brasilenols are likely to have a dietary origin, since these compounds have also been observed as natural products of the red seaweed Laurencia obtusa.     

Nucleophilic substitution in certain bicyclic sesquiterpene alcohols under chemical lonization conditions

Substitution of amino for hydroxyl groups in certain sesquiterpene alcohols has been studied by chemical ionization mass spectrometry using ammonia and ammouia-d₃ as the reagent gases, and by mass-analysed ion kinetic energy spectrometry and collision-induced decomposition mass-analysed ion kinetic energy measurements. Depending upon the source conditions and the nature of the substrates, both S_Ni and S_N1 mechanisms have been found to operate. No evidence is obtained for an S_N2 mechanism in these compounds. In centdarol and isocentdarol, addition of NH₃ to the double bond, followed by elimination of H₂O, also contributes to the substitution process. Attack of [NH₄]⁺ on the epoxide function, followed by loss of H₂O, appears to lead to the substitution ions in epoxycentdarol, epoxyisocentdarol and epoxyhimachalol.     

Chemical Constituent from the Twigs of Malaysian Syzygium griffithii

Chemistry of Natural Compounds -     

Influence of the substituting groups of sesquiterpene alcohols on the chemical shifts of C-methyl groups

Summary 1. The comparative influence of substituting groups on the chemical shifts of the C-methyl groups of sesquiterpene alcohols of the carotane and humlane series in dependence on the nature and position of the substituent has been studied.2. On the basis of the results obtained, a relative configuration of akitschenol has been put forward.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 584–587, September–October, 1978.     

Cytotoxic germacranolide sesquiterpene from Inula cappa

A new germacranolide, inulacappolide (1), was isolated from the EtOH extract of the whole plant of Inula cappa along with 16 known compounds. The structure of inulacappolide was a rare 1(10)-saturated type of germacran-6,12-olide, identified as 2alpha-acetoxy-3beta-hydroxy-9beta-angeloyloxygermacra-4-en-6alpha,12-olide by spectral analysis (IR, HR-ESI/MS, (1)H-NMR, (13)C-NMR, HMQC, HMBC, NOESY). In vitro, it showed antiproliferative effects against human cervical cancer HeLa, human leukemia K562 and human nasopharyngeal carcinoma KB cell lines with IC(50) values of 1.2 microM, 3.8 microM and 5.3 microM, respectively.     

A new sesquiterpene from Kalimeris integrifolia

A new sesquiterpene kalinturoside A (1), and 17 known compounds friedelan-3-ol (2), 24-ethyl-5a-cholesta-7, 22(E)-dien-3-one (3), friedelin (4), syringaresinol (5), α-spinasterol (6), ciwujiatone (7), syringic acid (8), scopoletin (9), apocynin (10), 1-(3-hydroxy-4, 5-dimethoxyphenyl)ethan-1-one (11), apigenin (12), 5-hydroxymethylfurfural (13), stigmasterol-3-O-β-d-glucopy-ranoside (14), bidenoside C (15), citrusin (16), irioresinol A (17) and syringaresinol-4-O-β-d-glucopyranoside (18) were isolated from the herbs of Kalimeris integrifolia. The structures of these compounds were elucidated using spectroscopic techniques such as NMR and MS. All of the compounds were isolated from this genus for the first time.     

杀虫植物苦皮藤毒杀成分的研究

从苦皮藤Celastrus angulatus Max.根皮中分离出5个对粘虫Mythimna separata (walker)具有毒杀活性的新化合物。经高分辨质谱和核磁共振谱鉴定其 结构为1α，2α,6β-三乙酰氧基－4β－羟基－8α－异丁酰氧基9β－呋喃甲酰氧 基－13－异戊酰氧基－β－二氢沉香呋喃（1），1α，2α，6β－二乙酰氧基－4 β－羟基8α，13－二异丁酰氧基－9β－苯甲酰氧基－β－二氢沉香呋喃（2）， 1α，2α，6β－三乙酰氧基－4β－羟基－8α－β异丁酰氧基－9β－苯甲酰氧基 －13－异戊酰氧基－β-二氢沉香呋喃（3），1α，6β，8α，13－四乙酰氧基－ 2α－羟基－9α－苯甲酰氧基－β－二氢沉香呋喃（4），1α，2α－二乙酰氧基 －4β，6β－二羟基－8β－异丁酰氧基9α－苯甲酰氧基－13－异戊酰氧基－β－ 二氢沉香呋喃（5）。它们对5龄粘虫的致死中量LD50分别为91.4,271.5，168.8, 388.0和135.5μg/g。     

A new sesquiterpene from Caragana intermediia

A new alloaromadendrane-type sesquiterpene,(-)-alloaromadendrane-3β,9β-diol(1),has been isolated from the aerial part of Caragana intermediia.The structure of (-)-alloaromadendrane-3β,9β-diol(1)was established by spectroscopic methods, including X-ray analysis that provided its relative stereochemistry.Bioassay showed that (-)-alloaromadendrane-3β,9β-diol (1)possesses anti-pyricularia oryzae P-2b activity with MIC value of 10μg/mL.     

Three new sesquiterpene hemiacetals from Achillea vermicularis

Three new sesquiterpene hemiacetals, tentatively named as achilleanone (1), vermiculone (2) and vermicularone (3) have been isolated from Achillea vermicularis, along with three other known compounds beta-amyrin, oleonolic acid and beta-sitosterol. The structure elucidation of new compounds was based primarily on two-dimensional (2D) NMR techniques including Nuclear Overhauser Effect/Enhancement (NOE), heteronuclear multiple quantum coherence (HMQC), heteronuclear multiple bond correlation (HMBC) and nuclear overhauser effect spectroscopy (NOESY) experiments. Compounds 1, 2 and 3 have displayed inhibitory potential against lipoxygenase enzyme in a concentration-dependent fashion with promising IC50 values.     

南蛇藤倍半萜成分研究

从南蛇藤(Celastrus angulatus)的种子中分得三个新的倍半萜化合物(1～3)。它们的结构经紫外、红外、质谱及二维核磁谱确定为1β-乙酰氧基-8α-苯甲酰氧基-9β, 13-二(β-吡啶甲酰氧基)-β-二氢沉香呋喃(1)-1β, 2β-二羟基-6α-乙酰氧基-8β, 9β-二苯甲酰氧基-β-二氢沉香呋喃(2)和1β, 2β, 8β, 9β-四苯甲酰氧基-6α-乙酰氧基-β-二氢沉香呋喃(3)。