Thiosulfate, S-alkyl

The formation of S-alkyl thiosulfate (Bunte salt) by the reaction of alkyl halide and sodium thiosulfate has been well known. Whereas a patent claimed the formation of Bunte salt from PECH and sodium thiosulfate (23), the reaction hardly proceeded in DMF owing to low solubility of sodium salt. On the other hand, both ammonium thiosulfate and PECH were soluble in HMPA-H20 (7 1 vol/vol) and the reaction proceeded homogeneously. Water soluble Bunte salt (j2, v(S0), 1200, 1020 cm-1) was isolated by pouring the reaction mixture into water and salting out with ammonium chloride. The DS based on the mercuric nitrate titration was in nearly accord with that on elemental analysis. The DS values depended on the thiosulfate concentration were shown below. 

Bunte salts Salts of S-alkyl thiosulfates with structure RSS(0)20 M+. calixarenes Cyclic oligomers formed from para-substituted phenols and formaldehyde. 

Sodium thiosulfate can also be used for preparation of thiols it is treated with an alkyl halide which converts it into the S-alkyl thiosulfate (Bunte salt), and this affords the thiol under reducing conditions (required to suppress formation of the disulfide) the Bunte salt need not be isolated. 

S-Alkyl thiosulfates are oxidized by elemental iodine to disulfides in excellent yield, probably without formation of the thiols as intermediates 278... 

Nucleophilic catalysis is also observed with iodide ions. Fluoride ion does not form nitrosyl fluoride under diazotization conditions, as is to be expected from Pearson s hard and soft acids and bases principle which was discussed briefly in Section 3.2. More recently, nucleophilic catalysis has also been shown to occur with thiocyanate ion (SCN ), thiosulfate ion (HS2Of), dimethyl sulfide, and thiourea (H2NCSNH2) or its alkyl derivatives (see below). 

The reaction of S-2-(alkylamino)ethyl thiosulfates, applied in the form of zwitterionic Bunte salts, with carbon disulfide in aqueous sodium hydroxide produces intermediate dithiocarba-mates, which cyclize with loss of sulfite anion from the thiosulfate moiety to give 4-alkyl-5,6-di-hydro-l,2,4-dithiazine-3(4/f)-thiones.28... 

Mechlorethamine is the only aliphatic nitrogen mustard currently on the U.S. market (Fig. 42.3). Its use is limited by extremely high reactivity, which leads to rapid and nonspecific alkylation of cellular nucleophiles and excessive toxicity. It is a severe vesicant, and if accidental skin contact occurs, the drug must be inactivated with 2% sodium thiosulfate (Na2S203) solution. This reagent reacts with the mustard to create an inactive, highly ionized, and water-soluble thiosulfate ester that can be washed away (Fig. 42.4). The affected tissue also should be treated with an ice compress for 6 to 12 hours. 

A series of trisubstituted alkenes containing (Z)-allylthio moieties as the key structural units, that is, sodium (Z)-allyl thiosulfates 338, symmetrical di[(Z)-allyl] sulfides 343 and di[(Z)-allyl] disulfides 339 and unsymmetrical diallyl sulfides 341 have been prepared in moderate to good yields via chemical transformations from the acetates of MBH adducts. In addition, it was found that the Sm and a trace amount of I2 could be used for the selective cleavage of the S-S or C-S bonds in sodium (Z)-allyl thiosulfates 338, depending on the substituents (alkyl or aryl group), to give the corresponding... 

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