- Enantiomeric synthesis of natural alkylglycerols and their antibacterial and antibiofilm activities
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Alkylglycerols (AKGs) are bioactive natural compounds that vary by alkyl chain length and degree of unsaturation, and their absolute configuration is 2S. Three AKGs (5l–5n) were synthesised in enantiomerically pure form, and were characterised for the first time together with 12 other known and naturally occurring AKGs (5a–5k, 5o). Their structures were established using 1H and 13C APT NMR with 2D-NMR, ESI-MS or HRESI-MS and optical rotation data, and they were tested for their antibacterial and antibiofilm activities. AKGs 5a–5m and 5o showed activity against five clinical isolates and P. aeruginosa ATCC 15442, with MIC values in the range of 15–125 μg/mL. In addition, at half of the MIC, most of the AKGs reduced S. aureus biofilm formation in the range of 23%–99% and P. aeruginosa ATCC 15442 biofilm formation in the range of 14%–64%. The antibiofilm activity of the AKGs assessed in this work had not previously been studied.
- Fernández Montoya, Deicy J.,Contreras Jordan, Luis A.,Moreno-Murillo, Bárbara,Silva-Gómez, Edelberto,Mayorga-Wandurraga, Humberto
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supporting information
p. 2544 - 2550
(2019/11/13)
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- Preparation method of nervonic acid and nervonic acid
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The invention discloses a preparation method of nervonic acid and nervonic acid. The preparation method comprises the following steps: preparing a Grignard reagent from 1-bromo-cis-13-docosaene, and carrying out an epoxy ring-opening reaction on the Grignard reagent, cuprous iodide and ethylene oxide to synthesize 1-hydroxy-cis-15-tetracosaene; and preparing nervonic acid by carrying out oxidationreaction on 1-hydroxy-cis-15-tetracosaene, iodobenzene acetate and TEMPO. By means of chemical synthesis, erucic acid is used as a raw material, and synthesis of nervonic acid is completed through esterification, reduction, bromination, Grignard reaction and oxidation. The method for synthesizing nervonic acid has the advantages of cheap and accessible raw materials, high yield, high product purity and the like, and is easy to operate.
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Paragraph 0049; 0052; 0056
(2020/07/27)
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- Highly chemoselective reduction of amides (primary, secondary, tertiary) to alcohols using SmI2/amine/H2O under mild conditions
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Highly chemoselective direct reduction of primary, secondary, and tertiary amides to alcohols using SmI2/amine/H2O is reported. The reaction proceeds with C-N bond cleavage in the carbinolamine intermediate, shows excellent functional group tolerance, and delivers the alcohol products in very high yields. The expected C-O cleavage products are not formed under the reaction conditions. The observed reactivity is opposite to the electrophilicity of polar carbonyl groups resulting from the nX → πC=O (X = O, N) conjugation. Mechanistic studies suggest that coordination of Sm to the carbonyl and then to Lewis basic nitrogen in the tetrahedral intermediate facilitate electron transfer and control the selectivity of the C-N/C-O cleavage. Notably, the method provides direct access to acyl-type radicals from unactivated amides under mild electron transfer conditions.
- Szostak, Michal,Spain, Malcolm,Eberhart, Andrew J.,Procter, David J.
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supporting information
p. 2268 - 2271
(2014/03/21)
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- Practical and scalable synthesis of (Z)-9-Tricosene, the housefly sex pheromone
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A practical and scalable synthesis of (Z)-9-tricosene, the sex pheromone of the housefly, has been achieved by the addition of one-carbon unit from the readily available (Z)-erucic acid. The synthesis is composed of three consecutive steps, lithium aluminium hydride reduction of erucic acid, tosylation of the resulting alcohol, and copper-catalyzed Kumada- type cross-coupling of the tosylate with methylmagnesium bromide as the key step. This approach is quite straightforward and capable of scale-up synthesis.
- Kim, Miri,Pitchaiah, Arigala,Park, No-Joong,Hwang, In Taek,Lee, Kee-In
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p. 628 - 631
(2013/02/23)
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- Synthesis and solution properties of cationic gemini surfactants with long unsaturated tails
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Gemini surfactants 22:1-s-22:1, where s = 2 and 6 methylene groups and 22:1 refer to erucyl dimethylammonium bromide chains, together with the monomeric surfactant erucyl bis-(hydroxyethyl) methylammonium bromide (EHAB) which has the same long unsaturated tails with gemini surfactants, were synthesized and characterized and solution properties of these surfactants were investigated using surface tension, conductivity and viscosity measurement. It has been found that the critical micelle concentration (cmc) values of 22:1-2-22:1 and 22:1-6-22:1 are 15.4 and 8.3 μM, respectively, less than the cmc value of EHAB (38 μM). On the other hand, the surface tension of 22:1-2-22:1 and 22:1-6-22:1 at cmc are 40.9 and 42.4, respectively, greater than the surface tension of EHAB (30.9 at cmc). Both 22:1-2-22:1 and 22:1-6-22:1 have nearly the same value of a0 (the minimum head group areas per surfactant molecule at the aqueous solution/air interface), which is almost the half value of a0 corresponding to EHAB. On the other hand, the ionization degree α of micelles of both 22:1-2-22:1 and 22:1-6-22:1 is approximately twice the value of α corresponding to micelles of EHAB. Though 22:1-2-22:1 has more similarity with 22:1-6-22:1 rather than EHAB as presented above, 22:1-2-22:1 in water cannot enhance the viscosity of the solution significantly in the presence of salt. In contrast, both 22:1-6-22:1 and EHAB in water can give rise to highly viscoelastic or gel-like solutions even at the high temperature in the presence of salt. In particular, 22:1-6-22:1 has proved to be a more efficient candidate for high temperature rheology-control applications than EHAB. The effect of salt upon the viscosity of 22:1-6-22:1 in aqueous solution is significant. The most proper ratio of 22:1-6-22:1/NaSal for enhancing the viscosity of solution has been proved to be 0.7.
- Li, Huazhen,Yang, Haiyang,Yan, Yunfei,Wang, Qin,He, Pingsheng
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experimental part
p. 1173 - 1178
(2010/08/21)
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- A simplified synthesis of (R)-(-)-muscone using a ring-opening reaction of (R)-(+)-β-methyl-β-propiolactone
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A chiral macrocyclic precursor can be constructed via a ring-opening reaction of (R)-(+)-β-methyl-β-propiolactone with a functionalized organocuprate with no loss of enantiomeric excess. The carboxylic acid precursor was used as a chiral building block for the synthesis of chiral muscone and musky macrolactones.
- Morita, Motoaki,Mase, Nobuyuki,Yoda, Hidemi,Takabe, Kunihiko
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p. 3176 - 3182
(2007/10/03)
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