Author
Yusuke Hirasawa
Other affiliations: University of Malaya, Hokkaido University, Airlangga University
Bio: Yusuke Hirasawa is an academic researcher from Hoshi University. The author has contributed to research in topics: Lycopodium & Indole alkaloid. The author has an hindex of 31, co-authored 195 publications receiving 3053 citations. Previous affiliations of Yusuke Hirasawa include University of Malaya & Hokkaido University.
Topics: Lycopodium, Indole alkaloid, Indole test, Quinolizidine, Cassia
Papers published on a yearly basis
Papers
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TL;DR: This review covered the structure elucidation and biological activity of new Lycopodium alkaloids and total synthesis of some Lycop sodium alkaloid reported in the literature from 2004 to July in 2008.
Abstract: Lycopodium alkaloids are unique heterocyclic alkaloids having C 11 N, C 15 N 2 , C 16 N, C 16 N 2 , C 22 N 2 , and C 27 N 3 types from genus Lycopodium and have attracted great interest from biogenetic and biological points of view as well as providing challenging targets for total synthesis This review covered the structure elucidation and biological activity of new Lycopodium alkaloids and total synthesis of some Lycopodium alkaloids reported in the literature from 2004 to July in 2008
220 citations
TL;DR: Quinazoline alkaloid, vasicinone, showed a vasorelaxant activity against phenylephrine-induced contraction of isolated rat aorta and a moderate in vitro antiplasmodial activity against Plasmodium falciparum.
Abstract: Bioassay-guided purification from the seeds of Peganum harmala led to the isolation of harmine (1), harmaline (2), vasicinone (3), and deoxyvasicinone (4). Harmine (1) and harmaline (2) showed a moderate in vitro antiplasmodial activity against Plasmodium falciparum. Quinazoline alkaloid, vasicinone (3), showed a vasorelaxant activity against phenylephrine-induced contraction of isolated rat aorta.
127 citations
TL;DR: Two novel alkaloids with an unprecedented tricyclic skeleton, cassiarins A and B, have been isolated from the leaves of Cassia siamea, and the structures were elucidated on the basis of spectroscopic data.
96 citations
83 citations
TL;DR: Sieboldine A (1) exhibited a potent inhibitory activity against acetylcholinesterase and modest cytotoxicity and the structure and relative stereochemistry were elucidated on the basis of 2D NMR data and X-ray analysis.
80 citations
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TL;DR: This tutorial review describes selected recent examples of how the metal-catalysed C-H bond functionalisation has been able to positively affect the synthesis of natural products.
Abstract: Metal-catalysed C–H bond functionalisation has had a significant impact on how chemists make molecules. Translating the methodological developments to their use in the assembly of complex natural products is an important challenge for the continued advancement of chemical synthesis. In this tutorial review, we describe selected recent examples of how the metal-catalysed C–H bond functionalisation has been able to positively affect the synthesis of natural products.
1,361 citations
22 Apr 2012
TL;DR: In this article, the electromagnetic spectrum in Figure 1 illustrates the many different types of electromagnetic radiation, including gamma rays (γ-rays), X-rays, ultraviolet (UV) radiation, visible light, infrared (IR), microwaves, and radio waves.
Abstract: Spectroscopy is the study of matter interacting with electromagnetic radiation (e.g., light). The electromagnetic spectrum in Figure 1 illustrates the many different types of electromagnetic radiation, including gamma rays (γ-rays), X-rays, ultraviolet (UV) radiation, visible light, infrared (IR) radiation, microwaves, and radio waves. The frequency (ν) and wavelength (λ) ranges associated with each form of radiant energy are also indicated in Figure 1.
849 citations
TL;DR: The applications of gold catalysed reactions in total synthesis during the years since the last article are reviewed and literature analysis is conducted to evaluate the progress in this field.
Abstract: In this critical review the applications of gold catalysed reactions in total synthesis during the years since our last article are reviewed. At the end of this article a literature analysis is conducted to evaluate the progress in this field.
617 citations
TL;DR: A new probability measure, which is termed DP4, complements the probabilities obtained from the previously developed CP3 parameter, which applies to the case of assigning a pair of diastereoisomers when one has both experimental data sets.
Abstract: GIAO NMR shift calculation has been applied to the challenging task of reliably assigning stereochemistry with quantifiable confidence when only one set of experimental data are available. We have compared several approaches for assigning a probability to each candidate structure and have tested the ability of these methods to distinguish up to 64 possible diastereoisomers of 117 different molecules, using NMR shifts obtained in rapid and computationally inexpensive single-point calculations on molecular mechanics geometries without time-consuming ab initio geometry optimization. We show that a probability analysis based on the errors in each 13C or 1H shift is significantly more successful at making correct assignments with high confidence than are probabilities based on the correlation coefficient and mean absolute error parameters. Our new probability measure, which we have termed DP4, complements the probabilities obtained from our previously developed CP3 parameter, which applies to the case of assig...
604 citations
TL;DR: The effect of HupA and other cholinesterase inhibitors (anti-AD drugs) on acetylcholine esterase activity in the rat cortex and butylCholine esters activity are compared.
533 citations