- Two amphoteric galactocerebrosides possessing a tri-unsaturated long-chain base from the leech (Hirudo nipponica)
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Six amphoteric galactocerebrosides were isolated from the land annelid (Hirudo nipponica). Two of them have a tri-unsaturated long-chain base, D-erythro-(4E,8Z,11Z)-docosasphingatrienine. The position and geometry of the double bonds in the long-chain base unit were determined on the bases of chemical and spectral data.
- Noda,Tanaka,Tsujino,Miura,Miyahara,Hayakawa
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- One and Two-Carbon Homologation of Primary and Secondary Alcohols to Corresponding Carboxylic Esters Using β-Carbonyl BT Sulfones as a Common Intermediate
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Herein we report the efficient one- and two-carbon homologation of 1° and 2° alcohols to their corresponding homologated esters via the Mitsunobu reaction using β-carbonyl benzothiazole (BT) sulfone intermediates. The one-carbon homologation approach uses standard Mitsunobu C-S bond formation, oxidation and subsequent alkylation, while the two-carbon homologation uses a less common C-C bond forming Mitsunobu reaction. In this latter case, the use of β-BT sulfone bearing esters lowers the pKa sufficiently enough for the substrate to be used as a carbon-based nucleophile and deliver the homologated β-BT sulfone ester, and this superfluous sulfone group can then be cleaved. In this paper we describe several methods for the effective desulfonylation of BT sulfones and have developed methodology for one-pot alkylation-desulfonylation sequences. As such, overall, a one-carbon homologation sequence can be achieved in a two-pot (four step) procedure and the two-carbon homologation in a two-pot (three step) procedure (three-pot; four step when C-acid synthesis is included). This methodology has been applied to a wide variety of functionality (esters, silyl ethers, benzyls, heteroaryls, ketones, olefins and alkynes) and are all tolerated well providing good to very good overall yields. The power of our method was demonstrated in site-selective ingenol C20 allylic alcohol two-carbon homologation.
- Bon, David J.-Y. D.,Ková?, Ond?ej,Ferugová, Vendula,Zále?ák, Franti?ek,Pospí?il, Ji?í
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p. 4990 - 5001
(2018/05/17)
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- Dammarane triterpenoids from Carnauba, Copernicia prunifera (Miller) H. E. Moore (Arecaceae), wax
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Phytochemical investigation from carnauba (Copernicia prunifera) wax led to the identification of sixteen dammarane–type triterpenes, including thirteen new characterized as: (24R*)-methyldammara-20,25-dien-3α-ol and a mixture of alkyl (24R*)-methyldammar-25-en-20-ol-3β-carboxylates, together with three previously described triterpenes: carnaubadiol, (24R*)-methyldammara-20,25-dien-3β-ol and (24R*)-24-methyldammara-20,25-dien-3-one. Moreover, four fatty alcohols (eicosanol, docosanol, tetracosanol and hexacosanol) as well as four sterols (cholesterol, campesterol, stigmasterol, and sitosterol) were also obtained. These compounds were isolated using classical chromatographic methods and their structures were determined by spectroscopic and chemical methods.
- De Almeida, Buana C.,Araújo, Bruno Q.,Barros, Elcio D. S.,Freitas, Samya D. L.,Maciel, Dayany S. A.,Ferreira, Ari J. S.,Guadagnin, Rafael C.,Vieira, Gerardo M.,Lago, Jo?o H. G.,Chaves, Mariana H.
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p. 1371 - 1376
(2017/07/13)
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- Acyl flavonoids, biflavones, and flavonoids from Cephalotaxus harringtonia var. nana
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A methanol extract of the leaves of Cephalotaxus harringtonia var. nana and its ethyl acetate (EtOAc)-soluble fraction demonstrated strong antitumor activity against A549 and HT-29 cell lines. The EtOAc-soluble fraction was purified by column chromatography and high-performance liquid chromatography (HPLC) using a reverse-phase column to yield three novel acyl flavonoids and a biflavonoid, along with 15 other known compounds that included flavonoids, biflavonoids, and other phenolics. The structures of the new compounds were elucidated using spectral data from HR-MS and NMR, including two-dimensional NMR studies, as (2R,3R)-3-O-eicosanoyltaxifolin (1), (2R,3R)-3-O-docosanoyltaxifolin (2), (2R,3R)-3-O-tetracosanoyltaxifolin (3), and 6-methyl-4′,7,7′-tri-O-methylamentoflavone (4). The isolated compounds, including the known compounds, were tested for possible antitumor activity; some of the biflavones were found to be active. The potent antitumor activity of the extract was attributed to Cephalotaxus alkaloids, such as homoharringtonine (20).
- Komoto, Noriko,Nakane, Takahisa,Matsumoto, Sachiko,Hashimoto, Shusuke,Shirota, Osamu,Sekita, Setsuko,Kuroyanagi, Masanori
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p. 479 - 486
(2015/09/21)
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- Nickel-butadiene catalytic system for the cross-coupling of bromoalkanoic acids with alkyl grignard reagents: A practical and versatile method for preparing fatty acids
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The knights who say Ni: A practical and convenient synthetic route to fatty acids involves the Ni-catalyzed alkyl-alkyl cross-coupling of bromoalkanoic acids and alkyl Grignard reagents in the presence of 1,3-butadiene as an additive (see scheme). Copyright
- Iwasaki, Takanori,Higashikawa, Kiyokazu,Reddy, Vutukuri P.,Ho, Willbe W. S.,Fujimoto, Yukari,Fukase, Koichi,Terao, Jun,Kuniyasu, Hitoshi,Kambe, Nobuaki
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supporting information
p. 2956 - 2960
(2013/03/28)
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- SINGLE-STAGE ESTERIFICATION OF OILS AND FATS
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A process for producing alkyl esters useful as biofuels and/or lubricants. An alkyl ester product produced by the process. The process comprises a single- stage reaction for esterifying a de-watered glyceride-containing feedstock with an anhydrous short chain alcohol in the presence of a basic esterification catalyst to produce a reaction product comprising alkyl esters and a reaction by-product comprising glycerol-containing substances and the catalyst-containing alcohol. The single-stage esterification reaction is conducted within a temperature and negative-pressure controllable vessel. The alkyl ester product is separated from the reaction by-product and may be further de-watered and/or purified. The catalyst-containing alcohol may be separated from the reaction by-product, de- watered and reused. The glycerol-containing substances may be separated from the reaction by-product and further purified. Useful glyceride-containing feedstocks include those prepared from plant or animal or fish materials, particularly those produced from seeds of mustard, canola, soybean, corn, cotton, flax and palm.
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Page/Page column 13-15
(2008/06/13)
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- A New Synthesis of Long Chain Acid Esters and Carbinols
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A versatile synthesis of difficulty accessible long chain acid esters and carbinols is described.The synthesis involves acylations at 2- and 5-positions of thiophene.Thioketalation of the resulting ketoesters followed by Raney nickel desulfurization yield acid esters which on LAH reduction give the corresponding carbinols.
- Rao, S. Jagadishwar,Bhalerao, U. T.,Tilak, B. D.
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p. 208 - 211
(2007/10/02)
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- A CONVENIENT SYNTHESIS OF 1-TRIACONTANOL
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1-Triacontanol, a new plant growth regulator, has been synthesised starting from stearic acid, and by two successive additions of six carbon units through enamine intermediates.
- Rama Rao, A. V.,Deshmukh, M. N.,Kamalam, M.
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p. 227 - 230
(2007/10/02)
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- NEW HYDROXY FATTY ACID FROM SEED OIL OF BALIOSPERMUM AXILLARE
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A fatty acid, found as a minor component in the seed oil of Baliospermum axillare, is shown to be the hitherto unknown 11,13-dihydroxytetracos-trans-9-enoic acid (axillarenic acid).Key Word Index - Baliospermum axillare; Euphorbiaceae; seed oil; 11,13-dihydroxytetracos-trans-9-enoic acid.
- Husain, Shahid,Ahmad, Moghis U.,Osman, S. M.
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