ChemInform Abstract: DETERMINATION OF PROLINE RING NONPLANARITY FROM PROTON SPIN-SPIN COUPLING CONSTANTS: APPLICATIONS TO TWO CYCLIC PENTAPEPTIDES

1982 ◽  
Vol 13 (18) ◽  
Author(s):  
A. C. II BACH ◽  
A. A. BOTHNER-BY ◽  
L. M. GIERASCH
Keyword(s):  
Proton Spin ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

Proton spin–spin coupling constants and intramolecular hydrogen bonding in bromine derivatives of 1,3-dihydroxybenzene

1976 ◽  
Vol 54 (14) ◽  
pp. 2228-2230 ◽  
Author(s):  
Ted Schaefer ◽  
J. Brian Rowbotham
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Proton Spin ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Hydroxyl Groups ◽  
Oh Groups ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
Derivatives Of

The conformational preferences in CCl4 solution at 32 °C of the hydroxyl groups in bromine derivatives of 1,3-dihydroxybenzene are deduced from the long-range spin–spin coupling constants between hydroxyl protons and ring protons over five bonds. Two hydroxyl groups hydrogen bond to the same bromine substituent in 2-bromo-1,3-dihydroxybenzene but prefer to hydrogen bond to different bromine substituents when available, as in 2,4-dibromo-1,3-dihydroxybenzene. When the OH groups can each choose between two ortho bromine atoms, as in 2,4,6-tribromoresorcinol, they apparently do so in a very nearly statistical manner except that they avoid hydrogen bonding to the common bromine atom.

Stereochemical Determination of Acyclic Structures Based on Carbon−Proton Spin-Coupling Constants. A Method of Configuration Analysis for Natural Products

1999 ◽  
Vol 64 (3) ◽  
pp. 866-876 ◽  
Author(s):  
Nobuaki Matsumori ◽  
Daisuke Kaneno ◽  
Michio Murata ◽  
Hideshi Nakamura ◽  
Kazuo Tachibana
Keyword(s):  
Natural Products ◽  
Proton Spin ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Spin Coupling Constants
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