938-79-4Relevant articles and documents
Lumutinines A-D, linearly fused macroline-macroline and macroline-sarpagine bisindoles from Alstonia macrophylla
Lim, Siew-Huah,Tan, Shin-Jowl,Low, Yun-Yee,Kam, Toh-Seok
, p. 2556 - 2562 (2011)
Four new linearly fused bisindole alkaloids, lumutinines A-D (1-4), were isolated from the stem-bark extract of Alstonia macrophylla. Lumutinines A (1) and B (2) represent the first examples of linear, ring A/F-fused macroline-macroline-type bisindoles, w
Macroline, akuammiline, sarpagine, and ajmaline alkaloids from Alstonia macrophylla
Lim, Siew-Huah,Low, Yun-Yee,Sinniah, Saravana Kumar,Yong, Kien-Thai,Sim, Kae-Shin,Kam, Toh-Seok
, p. 204 - 215 (2014)
A total of seventeen alkaloids, comprising six macroline (including alstofolinine A, a macroline indole incorporating a butyrolactone ring-E), two ajmaline, one sarpagine, and eight akuammiline alkaloids, were isolated from the stem-bark and leaf extracts
Neutral iridium catalysts with chiral phosphine-carboxy ligands for asymmetric hydrogenation of unsaturated carboxylic acids
Yang, Shuang,Che, Wen,Wu, Hui-Ling,Zhu, Shou-Fei,Zhou, Qi-Lin
, p. 1977 - 1980 (2017/03/09)
We developed neutral iridium catalysts with chiral spiro phosphine-carboxy ligands (SpiroCAP) for asymmetric hydrogenation of unsaturated carboxylic acids. Different from the cationic Crabtree-type catalysts, the iridium catalysts with chiral spiro phosphine-carboxy ligands are neutral and do not require the use of a tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (BArF?) counterion, which is necessary for stabilizing cationic Crabtree-type catalysts. Another advantage of the neutral iridium catalysts is that they have high stability and have a long lifetime in air. The new iridium catalysts with chiral spiro phosphine-carboxy ligands exhibit unprecedented high enantioselectivity (up to 99.4% ee) in the asymmetric hydrogenations of various unsaturated carboxylic acids, particularly for 3-alkyl-3-methylenepropionic acids, which are challenging substrates for other chiral catalysts.
Substrate evaluation of rhodococcus erythropolis SET1, a nitrile hydrolysing bacterium, demonstrating dual activity strongly dependent on nitrile sub-structure
Coady, Tracey M.,Coffey, Lee V.,O'Reilly, Catherine,Lennon, Claire M.
supporting information, p. 1108 - 1116 (2015/02/19)
Assessment of Rhodococcus erythropolis SET1, a novel nitrile hydrolysing bacterial isolate, has been undertaken with 34 nitriles, 33 chiral and 1 prochiral. These substrates consist primarily of β-hydroxy nitriles with varying alkyl and aryl groups at the β position and containing in several compounds different substituents α to the nitrile. In the case of β-hydroxy nitriles without substitution at the α position, acids were the major products obtained, along with recovered nitrile after biotransformation, as a result of suspected nitrilase activity of the isolate. Unexpectedly, amides were found to be the major hydrolysis product when the β-hydroxy nitriles possessed a vinyl group at this position. To probe this behaviour further, additional related substrates were evaluated containing electron-withdrawing groups at the α position, and amide was also observed upon biotransformation in the presence of SET1. Therefore this novel isolate has also demonstrated NHase activity with nitriles that appears to be substrate-dependent.
