5466-78-4Relevant articles and documents
Catalytic, Enantioselective β-Protonation through a Cooperative Activation Strategy
Wang, Michael H.,Barsoum, David,Schwamb, C. Benjamin,Cohen, Daniel T.,Goess, Brian C.,Riedrich, Matthias,Chan, Audrey,Maki, Brooks E.,Mishra, Rama K.,Scheidt, Karl A.
, p. 4689 - 4702 (2017/05/12)
The NHC-catalyzed transformation of unsaturated aldehydes into saturated esters through an organocatalytic homoenolate process has been thoroughly studied. Leveraging a unique “Umpolung”-mediated β-protonation, this process has evolved from a test bed for homoenolate reactivity to a broader platform for asymmetric catalysis. Inspired by our success in using the β-protonation process to generate enals from ynals with good E/Z selectivity, our early studies found that an asymmetric variation of this reaction was not only feasible, but also adaptable to a kinetic resolution of secondary alcohols through NHC-catalyzed acylation. In-depth analysis of this process determined that careful catalyst and solvent pairing is critical for optimal yield and selectivity; proper choice of nonpolar solvent provided improved yield through suppression of an oxidative side reaction, while employment of a cooperative catalytic approach through inclusion of a hydrogen bond donor cocatalyst significantly improved enantioselectivity.
Total Synthesis and Biological Assessment of Novel Albicidins Discovered by Mass Spectrometric Networking
von Eckardstein, Leonard,Petras, Daniel,Dang, Tam,Cociancich, Stéphane,Sabri, Souhir,Gr?tz, Stefan,Kerwat, Dennis,Seidel, Maria,Pesic, Alexander,Dorrestein, Pieter C.,Royer, Monique,Weston, John B.,Süssmuth, Roderich D.
supporting information, p. 15316 - 15321 (2017/10/20)
Natural products represent an important source of potential novel antimicrobial drug leads. Low production by microorganisms in cell culture often delays the structural elucidation or even prevents a timely discovery. Starting from the anti-Gram-negative antibacterial compound albicidin produced by Xanthomonas albilineans, we describe a bioactivity-guided approach combined with non-targeted tandem mass spectrometry and spectral (molecular) networking for the discovery of novel antimicrobial compounds. We report eight new natural albicidin derivatives, four of which bear a β-methoxy cyanoalanine or β-methoxy asparagine as the central α-amino acid. We present the total synthesis of these albicidins, which facilitated the unambiguous determination of the (2 S,3 R)-stereoconfiguration which is complemented by the assessment of the stereochemistry on antibacterial activity.
AMIDATION METHOD AND ESTERIFICATION METHOD USING SULFONIC ACID HALIDE
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Paragraph 0038, (2017/01/17)
PROBLEM TO BE SOLVED: To provide a safe and economical method for rapidly synthesizing amides and esters in high yield. SOLUTION: There is provided a method for amidating an amine or a derivative thereof using a sulfonic acid halide, where a sulfonic acid halide is allowed to act as an activator on a carboxylic acid or a derivative thereof to synthesize an active ester, and the active ester is reacted with an amine or a derivative thereof as a nucleophile to amidate the amine or the derivative thereof to obtain a corresponding amide or a derivative thereof. In a similar manner, a sulfonic acid halide is allowed to act as an activator on a carboxylic acid or a derivative thereof to synthesize an active ester, and the active ester is reacted with an alcohol or a derivative thereof as a nucleophile to esterify the alcohol or the derivative thereof to obtain a corresponding ester or a derivative thereof. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2016,JPO&INPIT
