Identification of 5,9-hexadecadienoic acid in the marine spongeChondrilla nucula

The fatty acid 5,9-hexadecadienoic was identified in the spongeChondrilla nucula. This is the shortest fatty acid with the Δ5,9 unsaturation yet isolated from a marine sponge.     

Identification of the new 18-hexacosenoic acid in the spongeThalysias juniperina

The phospholipid fatty acids from the spongeSpheciospongia cuspidifera were studied revealing the presence of the rare 10-octadecenoic acid (10−18∶1) and a new 2-methoxyhexadecenoic acid. The phospholipid fatty acids fromThalysias juniperina were also studied revealing the presence of the hitherto unreported 18-hexacosenoic acid (18−26∶1). These results tend to indicate that the biosynthetic pathway from 10−18∶1 to 18−26∶1 may be operative in nature. The phospholipid mixture from the sponges was also analyzed by³¹P-NMR and shown to mainly consist of phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, and phosphatidylglycerol. Phosphatidylcholine was not found in the sponges analyzed in this work.     

Identification of naturally occurringtrans,trans Δ5,9 fatty acids from the spongePlakortis halichondroides

The firsttrans fatty acids from a sponge have been isolated fromPlakortis halichondroides. The sponge was shown to contain theiso acids (5E,9E)-19-methyl-5,9-eicosadienoic, (5E,9E)-20-methyl-5,9-heneicosadienoic and (5E,9E)-21-methyl-5,9-docosadienoic acid, as well as theanteiso acids (5E,9E)-19-methyl-5,9-heneicosadienoic and (5E,9E)-20-methyl-5,9-docosadienoic acid together with the straight chain (5E,9E)-5,9-docosadienoic acid. The acids were shown by gas chromatography, Fourier transform infrared and¹³C nuclear magnetic resonance to contain thetrans configuration. An eicosadienoic acid, namely (6E,14E)-6,14-eicosadienoic acid, and 12-methyl-5-octadecenoic acid were also identified in a sponge for the first time. The fatty acids were shown to be the principal constituents of phosphatidylethanolamine and phosphatidylcholine. No sterols were found in the sponge. The results presented in this work should be helpful in taxonomy of Homoscleromorpha.     

Occurrence of 7-methyl-7-hexadecenoic acid,the corresponding alcohol, 7-methyl-6-hexadecenoic acid,and 5-methyl-4-hexadecenoic acid in sperm whale oils

Two sperm whale oils from the northern hemisphere and two from the southern hemisphere were fractionated. Triglyceride and wax esters were examined for fatty acids and alcohols with monoethylenic unsaturation bearing a methyl branch on an ethylenic carbon. The 7-methyl-7-hexadecenoic acid (0.37-1.37%) was accompanied by the corresponding alcohol (0.28-0.72%), but these materials were not accompanied by shorter chain homologues. The 7-methyl-6-hexadecenoic acid was relatively less important (0.23-0.68%), but was accompanied by 5-methyl-4-hexadecenoic acid (0.10-0.39%), and a partially identified C13 compound. Chromatographic properties on silver nitrate impregnated silicic acid TLC and on three GLC liquid phases are reported.     

Occurrence of 7-methyl-7-hexadecenoic acid,the corresponding alcohol, 7-methyl-6-hexadecenoic acid,and 5-methyl-4-hexadecenoic acid in sperm whale oils

Journal of the American Oil Chemists' Society -     

The fatty acid composition of a Vibrio alginolyticus associated with the alga Cladophora coelothrix. Identification of the novel 9-methyl-10-hexadecenoic acid

The fatty acid composition of a new strain of Vibrio alginolyticus, found in the alga Cladophora coelothrix, was studied. Among 38 different fatty acids, a new fatty acid, 9-methyl-10-hexadecenoic acid and the unusual 11-methyl-12-octadecenoic acid, were identified. Linear alkylbenzene fatty acids, such as 10-phenyldecanoic acid, 12-phenyldodecanoic acid and 14-phenyltetradecanoic acid, were also found in V. alginolyticus. The alga contained 43% saturated fatty acids, and 28% C₁₆–C₂₀ polyunsaturated fatty acids of the n−3 and n−6 families.     

5-甲基-4-异噁唑甲酰氯的合成研究

以乙酰乙酸乙酯为起始原料,经与原甲酸三乙酯缩合,与盐酸羟胺环合,再经酯水解和酰氯化得标题化合物,４步总收率在３０％以上,产品含量在９９％以上。     

1-甲基-3-正丙基吡唑-5-甲酸合成中环合工艺研究

以2-戊酮和草酸二乙酯为原料,经缩合、环合、甲基化、水解等四步反应合成了西地那非的关键中间体-1-甲基-3-正丙基吡唑-5-甲酸。分别讨论了环化反应中反应时间,反应温度及物质配比对产物收率的影响,确定了最佳反应条件。     

6-methyl-8-hexadecenoic acid: A novel fatty acid from the marine spongeDesmapsama anchorata

The novel fatty acid 7-methyl-8-hexadecenoic (1) was identified in the marine spongeDesmapsama anchorata. Other interesting fatty acids identified were 14-methyl-8-hexadecenoic (2), better known through its methyl ester as one of the components of the sex attractant of the female dermestid beetle, and the saturated fatty acid 3-methylheptadecanoic (3), known to possess larvicidal activity. The main phospholipid fatty acids encountered inD. anchorata were palmitic (16∶0), behenic (22∶0) and 5,9-hexacosadienoic acid (26∶2), which together accounted for 50% of the total phospholipid fatty acid mixture.     

1-甲基-3-正丙基-5-吡唑羧酸的合成研究

以草酸二乙酯和2 戊酮为原料,经claiseen酯缩合、环化、水解三步反应合成出1 甲基 3 正丙基 5 吡唑羧酸,总收率73.26%,化合物用红外、核磁、元素分析等手段进行了结构表征。     

3-甲基-2-丁烯-1-醇的制备新工艺

研究了以溴代异戊烯水解工艺和精馏分离工艺为基础来制备3-甲基-2-丁烯-1-醇的新工艺。通过优化溶剂种类得到当水解溶剂为偶极类溶剂乙腈时,得到产物的选择性最高。并通过进一步优化实验操作条件,得到当溶剂加入量为v(乙腈):v(溴代异戊烯)=1:1,水解温度为70℃,碱用量为n(NaOH):n(溴代异戊烯)=1.2:1和反应时间为25min时,水解部分3-甲基-2-丁烯-1-醇的转化率最高可达63.35%。水解后的料液通过间歇精馏得到纯的3-甲基-2-丁烯-1-醇,最终的3-甲基-2-丁烯-1-醇总收率达到57.4%。     

A new cytotoxic fatty acid (5<Emphasis Type="Italic">Z</Emphasis>,9<Emphasis Type="Italic">Z</Emphasis>)-22-methyl-5,9-tetracosadienoic acid and the sterols from the far Eastern sponge <Emphasis Type="Italic">Geodinella robusta</Emphasis>

A new fatty acid, (5Z,9Z)-22-methyl-5,9-tetracosadienoic acid (1a), and a rare fatty acid, (5Z,9Z)-23-methyl-5,9-tetracosadienoic acid (2a), the predominant constituents of the free fatty acid fraction from the lipids of the sponge Geodinella robusta, were isolated and partly separated by reversed phase high-performance liquid chromatography, followed by multifold crystallization from MeOH to give 1a and 2a in 70% and 60% purity, respectively. These fatty acids were identified as (5Z,9Z)-22-and (5Z,9Z)-23-methyl-5,9-tetracosadienoic acids by nuclear magnetic resonance techniques, including distortionless enhancement by polarization transfer, heteronuclear multiple quantum connectivity, and correlation spectroscopy experiments, as well as from mass-spectrometric data for their methyl esters, the methyl esters of their perhydro derivatives, and their pyrrolidides. Mixtures of 1a and 2a showed cytotoxic activity against mouse Ehrlich carcinoma cells and a hemolytic effect on mouse erythrocytes. The sterol fraction from the same sponge was analyzed by gas liquid chromatography mass spectrometry, and 24-methylenecholesterol was identified as a main constituent of this fraction. The implications of the co-occurrence of membranolytic long-chain fatty acids and 24-methylenecholesterol as a main membrane sterol are discussed in terms of the phenomenon of biochemical coordination.     

Distribution oftrans-6-hexadecenoic acid, 7-methyl-7-hexadecenoic acid and common fatty acids in lipids of the ocean sunfishMola mola

Lipids extracted from various tissues of four individual sunfish have been shown to contain thetrans-6-hexadecenoic acid previously reported for marine turtles, a metridium and a jelly fish, and also the 7-methyl-7-hexadecenoic acid recently isolated from one sunfish liver oil sample. The other fatty acids present were qualitatively typical of marine lipids in general. Unusual quantitative details included high percentages of 18∶0 and 20∶4ω6, which are also found in the Atlantic leatherback turtle and presumably linked to a similar diet of jellyfish and to other common factors. In a sample of lipids from intestinal contentstrans-6-hexadecenoic acid was found to be the predominant C₁₆ monoene, and was accompanied by comparatively large amounts of the 7-methyl-7-hexadecenoic acid. This observation and other fatty acid details are compatible with an exogenous origin for these acids and jellyfish, etc., as a predominant dietary material for the ocean sunfish.     

Absorption of 2-butene and 2-methyl-2-butene in aqueous solutions of sulphuric acid

The kinetics of absorption of 2-butene in aqueous solutions of sulphuric acid was studied in a stirred cell in the range of acid concentration from 70·2 per cent w/w (11·5 g mole/l.) to 80·2 per cent w/w (14·56 g mole/l.). The absorption was found to conform to fast pseudo-first order mechanism. The pseudo-first order reaction rate constant at 28°C was found to vary from about 500 to 3·8 × 10⁶ sec^?1 over the above concentration range.The absorption of 2-methyl-2-butene (isoamylene) in aqueous solutions of sulphuric acid was also found to conform to fast psuedo-first order mechanism, in the range of acid concentration from 61·5 per cent w/w (9·395 g mole/l.) to 75 per cent w/w (12·845 g mole/l.). The pseudo-first order reaction rate constant at 30°C was found to vary from about 4·2 × 10⁵ to 2·2 × 10⁸ sec^?1 over the above concentration range.     

Occurrence of 5,9,19-octacosatrienoic, 5,9-hexacosadienoic and 17-hexacosenoic acids in the marine spongeXestospongia halichondroides

The marine spongeXestospongia halichondroides contains 13% 28∶3Δ5,9,19, 27% 26∶2Δ5,9, and 21% 26∶1Δ17 in its total fatty acids. Thecis-5,cis-9,cis-19-octacosatrienoic acid structure is unknown in other living organisms.     

Adsorption and desorption characteristics of 2-methyl-4-chlorophenoxyacetic acid onto activated carbon

Adsorption and desorption characteristics of the 2-methyl-4-chlorophenoxyacetic acid (MCPA) from aqueous solution onto the activated carbon (GAC, F-400) were studied. Adsorption equilibrium capacities of the MCPA increased with decreasing pH and temperature of the solution. Adsorption equilibrium of the MCPA could be represented by the Sips equation. The internal diffusion coefficients were determined by comparing the experimental concentration decay curves with those predicted from surface diffusion model and pore diffusion model. The adsorption model based on the linear driving force approximation (LDFA) was used for simulating the adsorption behavior of the MCPA in a fixed bed. Over ninety five percent desorption of the MCPA could be obtained using distilled water.     

Enantioselective hydrogenation of 2-methyl-2-pentenoic acid over cinchonidine-modified Pd/alumina

A chiral alkanoic acid was prepared with up to 52% excess of the (S) enantiomer by hydrogenating an,-unsaturated carboxylic acid with a cinchonidine-Pd/Al₂O₃ catalyst system. Favourable conditions are: high surface hydrogen concentration ( 60 bar hydrogen pressure, low catalyst concentration and apolar solvents), near ambient temperature and a cinchonidine/reactantmolar ratio of at least 0.4 mol%. It is proposed that high hydrogen solubility and the presence of 2-methyl-2-pentenoic acid reactant as dimers are advantageous for enantiodifferentiation.