13C NMR studies of heterocyclic naphtho- and anthraquinones. Deshielding effect on the carbonyl carbon with methyl substitution

2008 ◽  
Vol 46 (2) ◽  
pp. 191-194 ◽  
Author(s):  
Cristian Salas ◽  
Veronica Armstrong ◽  
Claudio López ◽  
Ricardo A. Tapia
1989 ◽  
Vol 29 (1) ◽  
pp. 83-88 ◽  
Author(s):  
J. P. Grivet ◽  
J. Stevani ◽  
G. Hannequart ◽  
M. Durand

1999 ◽  
Vol 23 (3) ◽  
pp. 202-203
Author(s):  
Daniel A. Fletcher ◽  
Brian G. Gowenlock ◽  
Keith G. Orrell ◽  
David C. Apperley ◽  
Michael B. Hursthouse ◽  
...  

Solid-state and solution 13C NMR data for the monomers and dimers of 3- and 4-substituted nitrosobenzenes, and the crystal structure of E-(4-CIC6H4NO)2 are reported.


2021 ◽  
pp. 1-12
Author(s):  
Gerasimos M. Tsivgoulis ◽  
Dimitris G. Vachliotis ◽  
Golfo G. Kordopati ◽  
Panayiotis V. Ioannou

Sulfonates are well-known substances with a variety of applications, e.g. as surfactants. On the other hand, bis(sulfonates) bearing hydroxyl or keto group(s) in between the sulfonate groups can be used with or without further modification as starting materials for the preparation of new type of molecules capable to form either complexes or in general supramolecular structures. The synthesis of three hydroxyl-bearing bis(sulfonates), 2-hydroxypropane-1,3-bis(sodium sulfonate) 4, DL-2,3-dihydroxybutane-1,4-bis(sodium sulfonate) 8, and sodium 2,3,4-trihydroxy-1-sulfonate 7 (as by-product) via the Strecker sulfonation are described. Interestingly, under similar conditions, sulfonation of 1,4-dibromo-2,3-butanedione 9 was found to be very complicated and no pure product could be isolated, despite previously reported results on sulfonation of α-halogenated ketones in high yields. There are indications that SO3 2 -  attacks at the carbonyl carbon of 9 followed by rearrangement and expulsion of SO4 2 - . 1,4-dibromo-2,3-butanedione 9, bearing two keto groups next to methylene groups, can potentially exist as enols or in the case of its solution in hydroxylic solvents in the form of hemiketals or geminal diols. This behavior of 9 when is dissolved in CDCl3, CD3OD and D2O was studied by means of UV-Vis, 1H and 13C NMR and the nature of the adducts formed was elucidated.


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