Edward R. Cole

Structure and solution equilibria of D-glucose and D-mannose sulfite adducts.

An X-ray crystallographic study has confirmed that the potassium bisulfite adducts of D-glucose and D-mannose have open-chain structures with R and S configurations respectively at C-1. NMR studies have shown that each sugar gives rise to two bisulfite compounds, and solution-state structures and conformations of these isomers have been deduced from analysis of (1)H NMR spectra. (13)C NMR data for the four adducts are given. Furanose forms of the D-glucose and D-mannose have been detected in the equilibrium solutions.

COMPARATIVE REACTIVITIES OF ALKYL SELENOSULFATES (SELENO-BUNTE SALTS) AND ALKYL THIOSULFATES (BUNTE SALTS) WITH CYSTEINE

Abstract The comparative reactivities towards cysteine (CySH) of potassium benzyl selenosulfate, potassium p-nitrobenzyl selenosulfate and their thiosulfate isologues have been examined in neutral and slightly acidic media. The selenosulfates (RSeSO− 3) reacted more rapidly and gave better yields of products than the thiosulfates (RSSO− 3) at pH 5 and pH 7 and in each series p-nitrobenzyl derivatives reacted more completely than the benzyl. The products from both types of compound were the cysteine derivatives RX–SCy and CyS–SO− 3 together with the symmetrical diselenides/disulfides RXXR (X = S or Se). In each class of compound the p-nitrobenzyl derivatives produced a greater percentage of RXXR, at the expense of RX–SCy. The nature and distribution of products indicated that several competing reactions were proceeding simultaneously. An investigation of mechanistic possibilities by way of model systems suggested that, in the case of the selenosulfates, the initial products were RSe–SCy plus SO2- 3 which r...

SULFENAMIDES AND SULFINAMIDES V CONJUGATIVE AFFINITY AND pKa VALUES OF ARYL SULFINAMIDES

Abstract pKa values and NMR properties of aryl sulfinamides are discussed with respect to conjugative affinity in the sulfinamido group.

SULFENAMIDES AND SULFINAMIDES II1 INTERCHANGE REACTIONS OF AROMATIC SULFENAMIDES

Abstract A study has been made of photocatalyzed interchange reactions of aromatic sulfenamides. The significance of the results in relation to the relative ease of S[sbnd]N and S[sbnd]S bond fission is discussed, together with possible mechanisms of interchange. Relevance to industrial processes is noted.

Thiosulfonate Preparation By The Thiosulfinate/Sulfinic Acid Reaction

Abstract The reaction of thiosulfinates with amine salts of aryl sulfinic acids has been examined for the preparation of thiosulfonates, particularly unsymmetrical derivatives.

SULFENAMIDES AND SULFINAMIDES X OXIDATION OF THIOLS BY ARYL SULFINAMIDES

Abstract A dissection has been made of the oxidation of thiols by aryl sulfinamides, with the process explained by initial protonation of the sulfinyl group followed by a series of nucleophilic displacements, the first of which gives thiosulfinate and elimination of amine. The more usual reaction with thiosulfinate then gives disulfide, and sulfenic acid as a transitory intermediate, which by reaction with a third mode of thiol yields more disulfide. Reactions with lesser amounts of thiol permitted identification of intermediates. The effect of activation of the thiol is discussed. In contrast with oxidations by simpler sulfoxides the reaction proceeds without acid catalysis at ambient temperature, confirming the susceptibility to fission of the S—N bond in polar reactions.

Sulfenamides and Sulfinamides IX Exchange Reactions of Aryl Sulfinamides

Abstract A polar mechanism, associated with hydrogen bonding and emphasizing the ease of fission of the S–N bond, is proposed for the exchange reactions of aryl sulfinamides at ambient temperature. The mechanism starting with simple mixtures of sulfinamides extends to unlike combinations of sulfinamides with sulfenamides or amines. Results have bearing on the racemization of optically active sulfinamides.

SULFENAMIDES AND SULFINAMIDES IV. HOMOLYSIS OF SULFENAMIDES IN CYCLOHEXENE

Abstract The photocatalysed decomposition of aromatic sulfenamides in cyclohexene is a rapid reaction at ambient temperature. Products fall into two main groups resulting from recombination of initially formed radicals and from intervention of solvent acting as a radical trap.

Sulfenamides and Sulfinamides XI.†; Oxidation of Iodide Ion by an Aryl Sulfinamide

Abstract Oxidation of hydriodic acid by an aryl sulfinamide produced iodine in excess of the stoichiometric amount given by sulfoxides. The excess is explained by a secondary reaction with sulfenamide, the initial product, but is lessened by tertiary reactions including the formation of iodoaniline.

The thiosulfinate inhibition of methacrylate polymerization

Abstract Substituent influence on the efficiencies of a series of aryl thiosulfinates in inhibiting the polymerization of methyl methacrylate, representative of vinyl monomers, has been examined. Attention is drawn to the role of the sulfinyl group in reactions of organosulfur compounds.