Relations between Acetylcholine, Choline and Betaine Chains in Aqueous Solution

Structure of choline chloride-carboxylic acid deep eutectic solvents by wide-angle X-ray scattering and DFT calculations

“…This conclusion is consistent with the structure in the ChCl crystal, where the Ch + arranges in the gauche conformation in the crystal. 45 Meanwhile, it is consistent with our previous DFT calculations and Raman spectra results. 46 As Fig.…”

“…The ESP on the molecular surfaces of Ch-gauche, Ch-trans, FA and AA are shown in Fig.2a. The higher ESP of the hydroxyl group (121.81 kcal mol À1 ) and quaternary ammonium groups (96 45. 120.38 kcal mol À1 ) in Ch-gauche and 115.90 kcal mol À1 , 98.92-122.80 kcal mol À1 , in Ch-trans, respectively, which are the two main action sites that interact with anions.…”

The possible role of conformational isomerism in the biological actions of acetylcholine: spectral studies

“…Thus if C-H ----0 hydrogen bonding is present in acetylcholine in deuterium oxide solution then interchange between hydrogen bonded and nonhydrogen bonded species is probably too fast at room temperature to be detectable by nmr spectroscopy (Pople, Schneider & Bertstein, 1962). CONCLUSIONS From the above discussion it is apparent that the results are not incompatible with the existence of intramolecularly hydrogen bonded forms such as the quasi-ring structures (2 and 3) which exist in the crystalline state (Canepa & others, 1966) and in aqueous solution (Canepa, 1965;Culvenor & Ham, 1966), respectively. The high ester carbonyl stretching frequency of acetylcholine although perhaps best interpreted in terms of an inductive effect from the onium nitrogen atom can also be interpreted in terms of C-H ----0 hydrogen bonding between one of the N-methyl groups and the acetoxy oxygen atom.…”

“…Although the inductive effect of the quaternary ammonium group as shown in ( I ) would explain (compare Jones & Sandorfy, 1956) the observed high carbonyl absorption frequency in the infrared spectum of acetylcholine (Fellman & Fujita, 1962, 1965, 1966 as well as the From the Department of Pharmacy, University of Strathclyde, Glasgow, C.l. high electrophilicity of the ester carbonyl carbon atom as evidenced by kinetic studies (Butterworth, Eley & Stone, 1953;Fellman & Fujita, 1962) [despite challenge of this interpretation by Canepa & Mooney (1965)], it is also possible that the kinetic results and the infrared carbonyl frequency are the result of electron withdrawal from the carbonyl group via the acyloxy oxygen atom due to hydrogen bonding (4).…”

“…In contrast to other comparative infrared studies (Fellman & Fujita, 1962, 1965, 1966 which were primarily concerned with establishing the influence of the inductive effect from the quaternary ammonium group ( I ) , our studies were undertaken in an attempt to establish whether or not the cyclic conformation (2) of acetylcholine owed its stability to intramolecular NC-H ----0 hydrogen bonding as suggested by Sutor (1962Sutor ( , 1963 and Whittaker (1963). The evidence leading to the conclusion that the cyclic conformation 2, or the similar conformation 3,…”