7465-57-8Relevant articles and documents
A study of modified betaines as cryoprotective additives
Lloyd,Olliff,Rutt
, p. 704 - 707 (2007/10/02)
Glycinebetaine and N-modified betaines have been previously shown to be effective at reducing leakage from liposomes on freeze-thaw procedures. This study involved the preparation of a series of other modified betaines and the comparison of their abilities to reduce leakage from frozen multilamellar liposomes. All the compounds investigated, with the exception of the octyl ester of betaine, reduced the degree of leakage on freezing and thawing with additive concentrations up to 0.6 M. The betaine esters were less effective than betaine as cryoprotective additives and caused an increase in the leakage from unfrozen liposomes. Taurinebetaine, a sulphobetaine, was also less effective at reducing leakage on freezing than betaine and again increased leakage from unfrozen liposomes. Increasing the number of methylene groups between the carboxylate group and the nitrogen improved the ability to reduce leakage, particularly at lower additive concentrations.
Organic sulfur mechanisms. 24. Preparation and reaction of 2-hydroxyethanesulfonyl chloride, the first hydroxyalkanesulfonyl chloride
King, James Frederick,Hillhouse, John Henry
, p. 1583 - 1593 (2007/10/02)
2-Hydroxyethanesulfonyl chloride (1a) is readily made by reaction of an aqeous solution of 2-mercaptoethanol (4a) with chlorine.This is the first clearly proved preparation of a compound which is both an alcohol and a sulfonyl chloride.Reactions of 1a with water and alcohols evidently proceed largely by intramolecular cyclization to the transient β-sultone (2a), which then undergoes nucleophilic ring opening to form the products.In the presence of tertiary amines a minor but significant part of the reaction is shown by deuterium labelling to proceed via hydroxymethylsulfene (14), the principal reaction of which is simply to add the alcohol or water; only a small part, if any, of the sulfene (14) loses the hydroxyl group to give the ethenesulfonate derivatives (13 or 22).Aqueous chlorination of 3-mercapto-1-propanol gave 3-chloro-1-propanesulfonyl chloride (5a) and 1,3-propane sultone (2b) with no sign of any 3-hydroxy-1-propanesulfonyl chloride (1b).A mechanism for the aqueous chlorination process invoking a cyclic chlorooxasulfoxonium ion (27) is discussed.
