Reactions of Organic Sulfonyl Chlorides

In this context our interest was focused on sulfonic acid esters of starch, derived fh)m the reaction of organic sulfonyl chloride (e.g. benzene, methane, or toluene sulfonyl chloride). These derivatives can be employed as partially protected and reactive intermediates. Up to now, especially the reaction of starch with p-toluenesulfonyl chloride in pyridine was studied, i.e. under heterogeneous reaction conditions, which may be accompanied by several side reactions. Alternatively, a homogeneous procedure was published using dimethyl sulfoxide as solvent for starch. However, the sulphur contents of the products were very low and an extensive degradation of the polymer occured . The extent of / toluenesulfonyIation of primary and secondary groups was determined by the iodination method. It was revealed that the reaction proceeds faster at 0-6 than at 0-2 and 0-2... 

Mannitol hexanitrate is obtained by nitration of mannitol with mixed nitric and sulfuric acids. Similarly, nitration of sorbitol using mixed acid produces the hexanitrate when the reaction is conducted at 0—3°C and at —10 to —75°C, the main product is sorbitol pentanitrate (117). Xylitol, ribitol, and L-arabinitol are converted to the pentanitrates by fuming nitric acid and acetic anhydride (118). Phosphate esters of sugar alcohols are obtained by the action of phosphorus oxychloride (119) and by alcoholysis of organic phosphates (120). The 1,6-dibenzene sulfonate of D-mannitol is obtained by the action of benzene sulfonyl chloride in pyridine at 0°C (121). To obtain 1,6-dimethanesulfonyl-D-mannitol free from anhydrides and other by-products, after similar sulfonation with methane sulfonyl chloride and pyridine the remaining hydroxyl groups are acetylated with acetic anhydride and the insoluble acetyl derivative is separated, followed by deacetylation with hydrogen chloride in methanol (122). Alkyl sulfate esters of polyhydric alcohols result from the action of sulfur trioxide—trialkyl phosphates as in the reaction of sorbitol at 34—40°C with sulfur trioxide—triethyl phosphate to form sorbitol hexa(ethylsulfate) (123). 

F. INTRAMOLECULAR RING CLOSURE OF a,o>-DIOLS USING ORGANIC SULFONYL CHLORIDES (THE OKAHARA RING-CLOSURE REACTION)... 

Reduction is a possible reaction of almost all sulfur-containing organic compounds. According to the conditions used it leads either to thiols or to disulfides. For these purposes importance attaches primarily to reduction of aromatic sulfonyl chlorides and hydrogenating cleavage of disulfides. 

In the nucleophilic substitution reactions of alkylsulfonyl chlorides and ring-substituted benzylsulfonyl chlorides, the operation of two competing reaction pathways has been established (a) E-A (sulfene) mechanism and (b) direct nucleophilic substitution at sulfur (general base catalysis). The relative significance of these competing mechanisms depends on the nature of the substrate and the precise reaction conditions. In the hydrolysis of cyclopropane-sulfonyl chloride 11 with tertiary amines in organic media, the sulfene 12 appears to be the crucial intermediate in the formation of cyclopropanesulfonic acid 13 (Equation 12). ... 

When crude aulfonyl chlorides were used as starting materials, the reaction mixture was washed with a suitable solvent to remove organic impurities. In the case of higher-melting crystalline sulfonyl chlorides, heating to 50 may be necessary to complete their reduction. The solution of the sulfinate salt may be kept overnight, if desired, with no decrease in the yield of sulfonyl cyanide. 

The 1,3,2-dioxastannolanes are important in organic synthesis because they can readily be derived from dialkyltin oxide and 1,2-diols, as in carbohydrates the reaction can be carried out in toluene in a few minutes under microwave irradiation.387 The dioxastannolanes can then be subjected to regioselective reaction with an electrophile such as an acyl chloride (Equation (140)) or sulfonyl chloride, or an isocyanate. The acylation or sulfonation can be carried out with catalytic amounts of the dialkyltin oxide, including the recoverable (C6F13CH2CH2)2Sn0.388... 

The majority of fluorescent probes are water-insoluble and must be dissolved in an organic solvent prior to addition to an aqueous reaction medium containing the DNA to be labeled. Suitable solvents are identified for each fluorophore, but mainly DMF or DMSO are used to prepare a stock solution. Some protocols utilize acetone when labeling DNA. However, avoid the use of DMSO for sulfonyl chloride compounds, as this group reacts with the solvent. For oligonucleotide labeling, the amount of solvent added to the reaction mixture should not exceed more than 20% (although at least one protocol calls for a 50% acetone addition—Nicolas etal., 1992). 

Oxetanes have also been synthesized by the immobilization of 2,2 -disubstituted 1,3-diols with polymer-bound sulfonyl chloride, followed by intramolecular cyclization/cleavage from the solid support (Scheme 17) <2005TL643>. One percent divinylbenzene (DVB) cross-linked polystyrene and polyethylene glycol (PEG) (average Mn 3400) were used as polymer support in this reaction, and in both cases the properties of the polymer support allowed rapid purification of the intermediate. Intermediates on the insoluble cross-linked polystyrene support could be washed with a range of organic solvents to remove insoluble impurities, whereas the soluble PEG supported products could be purified by recrystallization from isopropanol. This is thought to represent the first reported polymer-supported synthesis of oxetanes. 

Preparative Methods the most convenient preparation of (/ ,/ )-stilbenediamine is described in Organic Syntheses." Condensation of benzil and cyclohexanone in the presence of ammonium acetate and acetic acid (eq 1) produces a spirocyclic 2//-imidazole (mp 105-106 °C). Reduction with Lithium in THF/NH3 followed by an ethanol quench and hydrolysis with aqueous HCl (eq 2) affords the racemic diamine as a pale yellow solid (mp 81-82 °C). Resolution is achieved by multiple recrystallizations of the tartaric acid salts ifom water/ethanol. The sulfonamides are prepared by reaction of the enantiomeri-cally pure diamine with the appropriate anhydride or sulfonyl chloride in CH2CI2 in the presence of Triethylamine and a catalytic amount of 4-Dimethylaminopyridine (eq 3). 

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