A computational and spectroscopic study of the gas-phase conformers of adrenaline

The conformational landscapes of the neurotransmitter l-adrenaline (l-epinephrine) and its diastereoisomer pseudo-adrenaline, isolated in the gas phase and un-protonated, have been investigated by using a combination of mass-selected ultraviolet and infrared holeburn spectroscopy, following laser desorption of the sample into a pulsed supersonic argon jet, and DFT and ab initio computation (at the B3LYP/6-31+G*, MP2/6-31+G* and MP2/aug-cc-pVDZ levels of theory). Both for adrenaline and its diastereoisomer, pseudo-adrenaline, one dominant molecular conformation, very similar to the one seen in noradrenaline, has been observed. It could be assigned to an extended side-chain structure (AG1a) stabilized by an OH → N intramolecular hydrogen bond. An intramolecular hydrogen bond is also formed between the neighbouring hydroxyl groups on the catechol ring. The presence of further conformers for both diastereoisomers could not be excluded, but overlapping electronic spectra and low ion signals prevented further assignments.

[1]  Andy MacLeod,et al.  Making space for IT , 2005 .

[2]  H. Früchtl,et al.  The potential energy landscape of noradrenaline: An electronic structure study , 2005 .

[3]  J. Simons,et al.  Neurotransmitters in the gas phase: Infrared spectroscopy and structure of protonated ethanolamine , 2004 .

[4]  J. Simons,et al.  Beta-blocker conformations in the gas phase: 2-phenoxy ethylamine, its hydrated clusters and 3-phenoxy propanolamine , 2004 .

[5]  T. Mourik.  The shape of neurotransmitters in the gas phase: A theoretical study of adrenaline, pseudoadrenaline, and hydrated adrenaline , 2004 .

[6]  D. Clary,et al.  Predicting Conformations of Biomolecules: Application to a Noradrenaline Analogue , 2004 .

[7]  J. Simons,et al.  Neurotransmitters in the gas phase: hydrated noradrenaline , 2003 .

[8]  J. Simons,et al.  Hydration of neurotransmitters: a computational and spectroscopic study of a noradrenaline analogue, 2-amino-1-phenyl-ethanol , 2003 .

[9]  J. Simons,et al.  Neurotransmitters in the gas phase: a computational and spectroscopic study of noradrenaline , 2003 .

[10]  J. Simons,et al.  Protonated neurotransmitters in the gas-phase: clusters of 2-aminoethanol with phenol , 2003 .

[11]  J. Simons,et al.  Conformation, structure and molecular solvation: a spectroscopic and computational study of 2-phenoxy ethanol and its singly and multiply hydrated clusters , 2002 .

[12]  C. Ghio,et al.  Interplay of intra‐ and intermolecular H‐bonds for the addition of a water molecule to the neutral and N‐protonated forms of noradrenaline , 2002 .

[13]  J. Simons,et al.  Conformational Preferences of Neurotransmitters: Norephedrine and the Adrenaline Analogue, 2-Methylamino-1-phenylethanol , 2001 .

[14]  J. Simons,et al.  Conformational Preferences of Neurotransmitters: Ephedrine and Its Diastereoisomer, Pseudoephedrine , 2001 .

[15]  J. Simons,et al.  Conformational landscapes of aromatic amino acids in the gas phase : infrared and ultraviolet ion dip spectroscopy of tryptophan , 2001 .

[16]  K. Kleinermanns,et al.  Structures of catechol(H2O)1,3 clusters in the S0 and D0 states , 2000 .

[17]  J. Simons,et al.  Infrared Ion Dip Spectroscopy of a Noradrenaline Analogue: Hydrogen Bonding in 2-Amino-1-phenylethanol and Its Singly Hydrated Complex , 1999 .

[18]  C. Reynolds,et al.  A new approach to docking in the beta 2-adrenergic receptor that exploits the domain structure of G-protein-coupled receptors. , 1997, Journal of medicinal chemistry.

[19]  K. Kleinermanns,et al.  Structure and vibrations of catechol and catechol⋅H2O(D2O) in the S0 and S1 state , 1996 .

[20]  T. Bürgi,et al.  O–H torsional vibrations in the S0 and S1 states of catechol , 1994 .

[21]  L. Schäfer,et al.  Investigation of the molecular structure of catechol by combined microwave spectroscopy and AB initio calculations , 1990 .

[22]  T. Ha,et al.  A theoretical study of conformations and rotational barriers in dihydroxybenzenes , 1990 .

[23]  M. Onda,et al.  Microwave spectrum of catechol (1,2-dihydroxybenzene) , 1987 .