Structure of 5-Methyl-4-[(arylamino)methylene]-2,4-dihydro-3H-pyrazol-3-ones

1981 ◽  
Vol 34 (5) ◽  
pp. 1117 ◽  
Author(s):  
JE Rockley ◽  
LA Summers

5-Methyl-4-[(arylamino)methylene]-2,4-dihydro-3H-pyrazol-3-ones have been synthesized. Of the 12 possible tautomeric forms it has been shown that they exist as the (ary1amino)methylene tautomerwith intramolecular hydrogen bonding between the CO and exocyclic NH groups.

10.1002/jcc.2 ◽  
1996 ◽  
Vol 17 (16) ◽  
pp. 1804-1819 ◽  
Author(s):  
Attila Kov�cs ◽  
Istv�n Kolossv�ry ◽  
G�bor I. Csonka ◽  
Istv�n Hargittai

2019 ◽  
Vol 58 (14) ◽  
pp. 9443-9451 ◽  
Author(s):  
Song Xu ◽  
Hyuk-Yong Kwon ◽  
Daniel C. Ashley ◽  
Chun-Hsing Chen ◽  
Elena Jakubikova ◽  
...  

2012 ◽  
Vol 2012 (24) ◽  
pp. 4483-4492 ◽  
Author(s):  
Ronald K. Castellano ◽  
Yan Li ◽  
Edwin A. Homan ◽  
Andrew J. Lampkins ◽  
Iris V. Marín ◽  
...  

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3763
Author(s):  
Poul Erik Hansen

This review outlines methods to investigate the structure of natural products with emphasis on intramolecular hydrogen bonding, tautomerism and ionic structures using NMR techniques. The focus is on 1H chemical shifts, isotope effects on chemical shifts and diffusion ordered spectroscopy. In addition, density functional theory calculations are performed to support NMR results. The review demonstrates how hydrogen bonding may lead to specific structures and how chemical equilibria, as well as tautomeric equilibria and ionic structures, can be detected. All these features are important for biological activity and a prerequisite for correct docking experiments and future use as drugs.


RSC Advances ◽  
2015 ◽  
Vol 5 (77) ◽  
pp. 62331-62335 ◽  
Author(s):  
Ángel M. Valdivielso ◽  
Alba Catot ◽  
Ignacio Alfonso ◽  
Ciril Jimeno

A novel amphiphilic acylguanidine organocatalyst using intramolecular hydrogen bonding as a key structural motif is efficient for asymmetric aldol reactions of ketones in water at neutral pH.


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