Geochemical significance of tricyclic and tetracyclic terpanes in source rock extracts from the Offshore Niger Delta Basin,Nigeria

Tricyclic and tetracyclic terpanes are important constituents of crude oil and source rock extracts.However,they have not been reported in the Offshore Niger Delta Basin,Nigeria.Thus,the present study investigated the geochemical significance of tricyclic and tetracyclic terpanes in source rock extracts from the Offshore Niger Delta Bain,Nigeria with gas chromatography-mass spectrometry(GC-MS).The total relative abundances of tricyclic terpanes,C_(19)TT-C_(21)TT,and C_(23) TT in the rock samples ranged from 82.50 to 96.37%,50.08 to 74.17%,and 25.83 to 49.92%,respectively.These values showed the source rocks were formed from a mixed origin(terrestrial and marine).Among the tricyclic and tetracyclic terpanes identified in the rock extracts,the conventional(C_(20)TT,C_(23)TT,C_(24)TT,C_(24)TeT)and recent(Y1,X1,Z1)were more prominent than all others,indicating mixed input of terrigenous and marine organic matter.The C_(24)TT/C_(23)TT,C_(24)TeT/(C_(24)TeT+C_(26)TT),C_(19)TT/C_(23)TT,C_(20)TT/C_(23)TT,C_(25)TT/C_(24)TeT,C_(25)TT/C_(26)TT,C_(19)TT/C_(20)TT,C_(24)TeT/C_(26)TT,Z1/(Z1+C_(24)TT),and Y1/(Y1+C_(24)TT)in the rock samples range from 0.33 to 1.30,0.76 to 0.90,0.18 to 0.73,0.34 to 1.05,0.33 to 1.74,0.30 to 1.39,0.31 to0.89,1.66 to 4.33,0.36 to 0.83,and 0.34 to 0.79,respectively.These values further showed that the rock samples were formed from mixed input of terrigenous and marine organic matter and deposited under oxic to suboxic conditions in lacustrine-fluvial/deltaic environments.Also,the C_(24)TeT/C_(20)-26TT,C_(24)TeT/C_(30)HOP,and C_(23)TT/C_(30)HOP ranged from 0.16 to 0.45,0.02 to 0.42,and 0.01 to 0.48,respectively.This range of values suggests that source rocks were within immature to early mature stage.Thus,this study showed that tricyclic and tetracyclic terpanes were effective in determining the origin,depositional environments,and thermal maturity of source rocks in the Niger Delta Basin,Nigeria.

Study on the Total Synthesis of Et 743 and its Analogues: Synthesis of a Tricyclic Intermediate and its 11-Epimer

The tricyclic compound 1, a key intermediate of the pentacyclic core of Et 743 and its analogues, was synthesized. Its 11-epimer was found as the product of racemization when BOP was used as the coupling agent, but not when BOP-C1 used in the same reaction. The stereochemistry of both isomers was confirmed on basis of the 1H NMR and NOE-difference spectra.

An Efficient Synthesis of Ethyl 7-Chloro-6-fluoro-l-methyl-4-oxo-1, 4-dihydro-[1, 3]thiazeto[3, 2-a]quinoline-3-carboxylate as Intermediate of the Prulifloxacin Containing Tricyclic Fluoroquinolone

Novel ethyl 7-chloro-6-fluoro-l-methyl-4-oxo-1, 4-dihydro-[1, 3]thiazeto[3, 2-a]quino- line-3-carboxylate 2 was prepared from 3-chloro-4-fluoroaniline in eight steps. It can be used as a new intermediate for the synthesis of tricyclic fluoroquinolones.

Study on the Total Synthesis of Hainanolide－Construction of Tricyclic Intermediate（I）

Tricyclic compounds (4b-endo) and (4b-exo) are synthesized as the plausible intermediates of the total synhthesis of hainanolide by Lewis acid catalyzed intramolecular DielsAlder (IMDA) reaction.

Crystal Structure of a Tricyclic Compound C_(20)H)(28)O_6 Obtained through IMDA Reaction

The tricyclic compoun d (2) C20H28O6 has been synthesized through thereaction of IMDA. The crystals of the title compound(2A) were crystallized from etherin monoclinic space group C2 with a unit cell: a = 11. 301 (2), b=11-.863 (3 ), c =29. 59 (1) , β= 101. 02(5)°, V=3894. 246, Dc=1.2413 g/cm3, Z=8, F(000)=1568, Mr= 364. 00 R=0.055, R2=0. 055, μ= 535 cm-1, S(GOF) =0. 571. Theconfiguration of C2a-H in the title compound was found to be contrary to what wasexpected and a possible mechanism of reaction was proposed.

Study on the Total Synthesis of Hainanolide (Ⅱ)──An Unexpected Hydroperoxide Containing Tricyclic Skeleton

An unexpected compound, hydroperoxide (4) formed from (3), the exo-cycloaddition product, which was synthesized through the Lewis acid catlyzed intramolecular Diels-Alder (IMDA) reaction. Its structure was confirmed by spectra and X-Ray diffraction analysis, An 1O2oxidation mechanism was proposed.

The Inertia Indexes of One Special Kind of Tricyclic Graphs

Let G be a graph and A=(aij)n×n be the adjacency matrix of G, the eigenvalues of A are said to be the eigenvalues of the graph G, and to form the spectrum of this graph. The numbers of positive, negative and zero eigenvalues in the spectrum of the graph G are called positive and negative inertia indexes and nullity of the graph G, are denoted by p(G), n(G), η(G), respectively, and are collectively called inertia indexes of the graph G. The inertia indexes have many important applications in chemistry and mathematics. The purpose of the research of this paper is to calculate the inertia indexes of one special kind of tricyclic graphs. A new calculation method of the inertia indexes of this tricyclic graphs with large vertices is given, and the inertia indexes of this tricyclic graphs with fewer vertices can be calculated by Matlab.

Construction of Angularly Fused Tricyclic Compounds via Photo-induced Radical Cascade Cyclization

Photo-induced electron transfer (PET) of silyl enol ethers has been employed to synthesize several fused ring systems. However, the method has limited applicability due to its narrow substrate scope, low product yields, unsatisfactory stereo- and regioselectivity. Herein, we report a PET-triggered cascade reaction of silyl enolates that leads to the formation of angularly fused tricyclic scaffolds. The reaction exhibits broad substrate scope and excellent stereoselectivity. The regio- and stereoselectivity of this cascade reaction is elucidated via DFT calculation and conformational analysis.

Discovery and development of tricyclic matrinic derivatives as anti-diabetic candidates by AMPKαactivation

We found compound 12N-p-trifluoromethylbenzenesulfonyl matrinane(1)was a potent anti-diabetic agent.Thirty-five tricyclic matrinic derivatives were synthesized and determined for their stimulatory effects on glucose consumption in L6 myotubes,taking 1 as the lead.In high-fat diet(HFD)and STZ induced diabetic mice,9a significantly lowers blood glucose,improves glucose tolerance,and especially alleviates diabetic nephropathy and islet damage.Mechanism study indicates that 9a simultaneously targets mitochondrial complex I to increase AMP/ATP ratio,as well as liver kinase B1(LKB1)and calcium/calmodulindependent protein kinase(Ca MKK),which synergistically activates AMPKαand then stimulates glucose transporter 4(GLUT4)membrane translocation and 2-deoxyglucose(2-DG)uptake to exert anti-diabetic efficacy.Therefore,compound 9a with a novel structure is a promising anti-diabetic candidate with the advantage of multiple-target mechanism,worthy of further investigation.

Discovery and development of synthetic tricyclic pyrroloquinone （TPQ） alkaloid analogs for human cancer therapy

Natural products and their derivatives repre- sent a rich source for the discovery and development of new cancer therapeutic drugs. Bioactive components derived from natural sources including marine compounds have been shown to be effective agents in the clinic or in preclinical settings. In the present review, we present a story of discovery, synthesis and evaluation of three synthetic tricyclic pyrroloquinone （TPQ） alkaloid analogs as cancer therapeutic agents. Chemical synthesis of these compounds （BA-TPQ, TBA-TPQ, and TCBA-TPQ） has been accomplished and the mechanisms of action （MOA） and structure-activity relationships （SAR） have been investigated. In the past, the complexity of chemical synthesis and the lack of well-defined MOA have dampened the enthusiasm for the development of some makaluvamines. Recent discovery of novel molecular targets for these alkaloids （unrelated to inhibition of Topoisomerase II） warrant further consideration as clinical candidates in the future. In addition to the establishment of novel synthetic approaches and demonstration of in vitro and in vivo anticancer activities, we have successfully demonstrated that these makaluvamines attack several key molecular targets, including the MDM2-p53 pathway, providing ample opportunities of modulating the compound structure based on SAR and the use of such compounds in combination therapy in the future.

Tricyclic aromatic diterpanes found in the Tertiary sediments and their geochemical significance

One monoaromatic tricyclic diterpane and two aromatic tricyclic diterpanes were found in three low-maturity source rocks and five crude oils of the Tertiary Shahejie Formation in Shengli Oil Field. The compounds found include C19H28 (m/z 145, M+ 256) ring-C monoaromatic tricyclic terpane, C17H20 (m/z 209, M+ 224) and C18H22 (m/z 223,M+ 238) rings-B,C diaromatic diterpanes. The results show that these compounds are biomarkers of immature organic matter with a stability sequence of C18H22 】 C17H20 】 C19H28. The cleavage of ring-D of pentacyclic triterpanoids, such as oleanene, hopene, fernene, ursene, in the early stage of diagenesis may be one of the origin pathways of rings-B, C diaromatic tricyclic diterpanes.

Pulse radiolysis of one-electron oxidation of rare tricyclic nucleoside derivative

One-electron oxidation of N-4-desmethylwyosine(dYt), a derivative of rare tricyclic nu-cleoside wyosine with several oxidative radicals, has been studied by using pulse radiolysis. The transient spectra of the radicals dYt? and dYt(-H) and the pKa of the radical cation were measured. The rate constants of reactions of dYt with SO4-, SO3-, and OH radicals have been determined and related reaction mechanisms were discussed.

Asymmetric synthesis of ABC tricyclic systems in Daphniphyllum alkaloid

Efficient synthetic routs for the direct and rapid construction of[5-6-6]ABC tricyclic systems of daphmanidin A-type and calyciphylline A-type alkaloids have been successfully developed.For the daphmanidin A-type,the synthesis of[5-6-6]tricyclic framework utilize a HCl-mediated intramolecular Aldol reaction to construct the bicyclo[2.2.2]octane core and a thermal condensation to afford the ABC ring system.In addition,for the calyciphylline A-type,an improved synthesis of ABC[5-6-6]tricyclic system was developed,featuring an introduction of methyl ester group at C2 before the Pd-catalyzed intramolecular oxidative alkylation to construct the desired bowl-shape tricyclic core with stereochemical control.

Synthesis of ACE tricyclic systems of daphnicyclidin A and dehy-droxymacropodumine A

The synthesis of the ACE tricyclic system of daphnicyclidin A and dehydroxymacropodumine A are developed.The key reactions include an efficient aldol reaction to introduce chiral fragment 33 for further construction of piperidine ring B and seven-membered ring C, a nucleophilic addition of lithium pentene to aldehyde for installation of ring E,and a photocatalytic decarboxylation conjugate addition to construct ring C.

Ordering of Spectral Moments of Tricyclic Graphs with Given Bases

The spectral moments are the important algebraic invariants of graphs.In this paper,on the basis of definitions of tricyclic graphs,base and the sequence of spectral moments,respectively,we study tricyclic graphs with given bases on the lexicographical order of the spectral moments sequence,and find the last and the first graphs.The results is very helpful for studying all tricyclic graphs ordering by spectral moments.

Navigating the Nomenclature of a Purported “Dietary Supplement”: A Cautionary Tale for Consumers and Practitioners Regarding Tianeptine or “Gas Station Heroin”

Dietary supplement sales have surpassed $30 billion per year with their use becoming and remaining extremely popular amongst the general public. There are numerous bioactive components, both nutritive and non-nutritive, in dietary supplements with considerable efficacy in promoting health. However, there are many ways disallowed ingredients may enter the supplement pipeline with potentially toxic effects. Dietary supplements can be regulated (either pre- or post-market) as a drug, dietary supplement, a nutraceutical, new dietary ingredient (NDI), generally recognized as safe (GRAS) food ingredient, a food additive, or a food. A pharmaceutical drug (medication) is used to treat, cure, prevent, or diagnose a disease and is regulated by the FDA pre-market only and allowed by medical prescription, whereas the other labeling designations are largely regulated post-market. One such molecule with a labeling problem is tianeptine, which has global use as an efficacious, prescribed drug, while at the same time being considered a non-drug and potentially dangerous adulterant often referred to as gas station heroin. In this paper, we critically evaluate the use and labeling of this compound and attempt to clarify the conundrum surrounding its legal or illegal use. Tianeptine is effective and efficacious as an antidepressant in those responding poorly to selective serotonin reuptake inhibitors (SSRIs) and exhibits many medicinal characteristics of tricyclic antidepressants with fewer opioid-like side effects. As a result, sixty-six countries permit use of tianeptine as a prescription drug. At higher doses, tianeptine has recently been shown to exhibit significant potential for abuse and dependency along with toxicity. As such, the US does not recognize tianeptine as an FDA-approved drug or as a dietary supplement, nutraceutical, new dietary ingredient (NDI), GRAS ingredient, or a food. Instead, tianeptine is a synthetic adulterant of a dietary supplement and considered technically an unapproved food additive. In conclusion, tianeptine, although viewed as a safe dietary supplement by many, is illegal in the US despite benefits to many but toxicity to others that make it vital that consumers and healthcare providers learn to critically evaluate and navigate the often confusing nomenclature of a purported dietary supplement to convey to the public whether it is efficacious, safe, and legal.

严重生物降解原油GC-MS特征及油源对比

图牧吉油砂位于松辽盆地边缘,搞清它的油源对于该地区的油气勘探有着十分重要的意义.气相色谱-质谱分析表明,该样品受到了严重的生物降解,部分用于对比的甾、萜烷生标标志物受到了降解,使与之有关的参数值发生了变化,给油源对比带来了困难.……

Prevalence, clinical features and treatment of depression in Parkinson's disease: An update

Parkinson's disease(PD) is one of the most prevalent neurodegenerative diseases which typically affects individuals over 65 years. Although the symptomatology is predominantly motor, neuropsychiatric manifestations, e.g., depression, apathy, anxiety, and cognitive impairment occur in the course of the illness and can have a great impact on the quality of life in these patients. Parkinson's disease is commonly comorbid with depression with prevalence rates of depression, generally higher than those reported in general population. Depression in PD is frequently underestimated andconsequently undertreated, which have significant effects on the quality of life in these patients. The neurobiology of depression in PD is complex and involves alterations in dopaminergic, serotonergic, noradrenergic and possibly other neurotransmitter systems which are affected in the course of the disease. The tricyclic antidepressants and the selective serotonin reuptake inhibitors are the two classes of antidepressant drugs used for depressive symptoms in PD. Several published studies suggested that both classes are of comparable efficacy. Other serotonergic antidepressants, e.g., nefazodone and trazodone have also been of benefit. Meanwhile, there are limited data available on other drugs but these suggest a benefit from the serotonin and noradrenaline reuptake inhibitors such as mirtazapine, venlafaxine, atomoxetine and duloxetine. Some of the drugs used in symptomatic treatment of PD, e.g., the irreversible selective inhibitors of the enzyme monoamine oxidase-B, rasagiline and selegiline as well as the dopamine receptor agonist pramipexole are likely to have direct antidepressant activity independent of their motor improving action. This would make these drugs an attractive option in depressed subjects with PD. The aim of this review is to provide an updated data on the prevalence, clinical features of depression in subjects with PD. The effects of antiparkinsonian and antidepressant drugs on depressive symptoms in these patients are also discussed.

Paediatric amitriptyline overdose

We report a near fatal case of paediatric amitriptyline overdose including a series of ECGs demonstrating the effects of sodium bicarbonate therapy on cardio-toxicity. We briefly discuss the role of sodium to counteract the sodium channel blockade of tricyclic antidepressants and discuss the possible utility of lipid emulsion therapy in such cases.