Methanesulfinates

In a formally similar reaction, the 4-methanesulfonyl-/3-lactam (95) undergoes displacement of methanesulfinate on treatment with propargylic or allylic alcohols in the presence of a Lewis acid catalyst to give a mixture of the cis- and tr<2Ms-4-alkoxy-/3-lactams (96) and (97) (79JCS(P1)2268). 

The utility of methanesulfinyl chloride lies in its great chemical reactivity. Through its ready hydrolysis, it serves as a convenient source of methanesulfinic acid. It reacts at low temperature with aromatic amines to form sulfinamides, and with alcohols to form sulfinate esters. When it is hydrolyzed in the presence of an equimolar quantity of sulfenyl chloride, a thiol-sulfonate ester is produced. 

Perfluoroalkylatwn ofpyridines by perfluoroalkyl bromides or iodides occurs m the presence of sulfur dioxide radical anion precursors, such as sodium hydroxy-methanesulfinate [755, 757, 158] (equation 135)... 

Nelson54 studied the products of radiolysis of aqueous solution by variable-field CIDNP pulse radiolysis. On the basis of the chemical shifts the following products were identified methyl methanesulfinate, methanol, l,2-bis(methylsulfinylethane) [CH3S(0)CH2CH2S(0)CH3], dimethyl sulfone, dimethyl sulfide, methane and ethane. The high field polarization was used to study the mechanism of formation of polarized products. 

Methyl methanesulfinate, CH30S(0)CH3, is formed by combination of methyl and methylsulfinyl radicals ... 

CN [sulfonylbis(4,l-phenyleneimino)]bis[methanesulfinic acidj disodium salt free acid... 

An inverse addition of suifinic acid to a thiocarbonyl group could have taken place with the reactive intermediate 8, which should arise from thiophosgene and methanesulfinic acid (sodium salt) (equation 28). The first step of this reaction represents an S-acylation... 

In a strongly acidic medium (FS03H—SbFs) methanesulfinic acid is readily protonated to give CH3S(OH) this species appears to be rather stable, showing no tendency to undergo cleavage reactions up to +65°C (Olah et al., 1970). 

We have previously mentioned the kinetic stabilization toward racemization of methyl methanesulfinate included in the cage-type clathrate of TOT (59). Such an effect may indeed be expected, since the cage wall is fairly rigid and the heat... 

Another frequently encountered problem is that of the solute that contains more than one possible site of secondary interaction. In such cases, one Bj generally dominates the other, and its incorrect identification often leads to incorrect configurational assignment to the solute. Acyclic sulfinate esters, for example, have two potential sites that could serve as B2, the electron pair on sulfur and the alkoxy oxygen. The nonequivalence predictions one would make in choosing either as B2 are different. Solvates 12 and 13 are the two possible solvation modes for t-butyl (/ )-methanesulfinate and an (5 )-carbinol (1). Principal operation of model 12 predicts a highfield... 

An attempt to directly resolve alkyl alkanesulfmates via 0-cyclodextrin inclusion complexes was only partly successful (35,106). In the majority of cases, the optical purity of the isolated esters was in the 5 to 10% range. In the case of isopropyl methanesulfinate, however, inclusion was highly stereospecific and afforded the ester with 68% optical purity. 

Esters of acetylenic alcohols and methanesulfinic and methanesulfonic acid have been used as synthetic intermediates in our laboratory, mainly for Sjsj2 -like substitution reactions leading to allenic derivatives [see for example refs. 210,211]. Although pyridine is recommended as... 

MSA concentrations were generally consistent with its formation from the OH-DMSO reaction if 80% of the reaction generated methanesulfinic acid and 50% of this compound was oxidized to MSA (Davis et al., 1998). 

When acetate, trifluoroacetate or methanesulfinate is employed as the leaving group, the optical yield is 65 %43. 

Sodium metapenodate, 55, 68 Sodium methanesulfinate, 57, 88 Sodium-potassium alloy, 57, 5 Sodium sulfide, nonahydrate, 57, 55... 

For dosimetry, the reaction of the reaction of OH with DMSO which yields methanesulfinic acid (92% Veltwisch et al. 1980 Chap. 3.2) is usually used. This allows one to put the conductance signals on a quantitative basis (calculation of G values), and the rates of reactions that are kinetically of first order can be determined for the time dependence of the signal evolution. DMSO dosimetry yields only a relative dose. For the determination of second-order rate constants, however, the exact dose must be known, and this can be determined by the zero conductivity change dosimetry or neutralization kinetics dosimetry (Schuchmann et al. 1991). 

In the all-in, also known as Rongalit C potash process, the print paste contains the dye and the chemicals necessary for fixation. The reducing agent hydroxy-methanesulfinate (Rongalit C), reaches its maximum reactivity under steaming conditions, but decomposes slowly already at room temperature [5, p. 296-298], Potassium carbonate (potash) is the preferred alkali. The dyes are fixed with saturated steam at 100-102°C for 5-15 min. The prints are then rinsed, reoxidized, neutralized, and soaped at the boil. 

Andersen, K. K., Bujnicki, B., Drabowicz, J., Mikolajczyk, M., and O Brien, J. B. (1984) Synthesis of enantiomerically pure alkyl and aryl methyl sulfoxides from cholesteryl methanesulfinates, J. Org. Chem. 49, 4070-4072. 

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