Thio-alkanes

It is of great value to know which types of sulphur compounds are present in a crude oil, because the various types may behave quite differently in respect to the properties of the crude and of the products that can be obtained from it by physical or chemical methods. According to recent investigations, in lower molecular oil fractions sulphur appears mainly in the form of alkane-thiols, cyclohexane-thiols and thio-alkanes in higher molecular fractions cyclic sulphur compounds of the thiophen type predominate. 

A further interesting example is the use of l,l-di(phenylthio)med)yllithium to open an epoxide followed by a Grob fragmentation process as shown in Scheme 56 (entry b). The reaction of 1,1-di-(thio)methyllithium with epoxides has also been used - in the one-pot synthesis of l,l-di(thio)cyclopropanes involving an intramolecular cyclization of the 7-tosyloxydi(phenylthio)alkylli-thium. This intramolecular alkylation reaction proceeds even more efficiently than its intermolecular version, and allows the synthesis of a large variety of l,l-di(thio)cyclopTDpanes from 3-chloro- and 3-phenylthio-l,l-di(thio)alkanes and n-butyllithium in THF (Scheme 57 and Scheme 58). 

The perfluoroalkane sulfonic acids were fkst reported ki 1954. Trifluoromethanesulfonic acid was obtained by the oxidation of bis(ttifluoromethyl thio) mercury with aqueous hydrogen peroxide (1). The preparation of a series of perfluoroalkanesulfonic acids derived from electrochemical fluotination (ECF) of alkane sulfonyl haUdes was also disclosed ki the same year (2). The synthetic operations employed when the perfluoroalkanesulfonic acid is derived from electrochemical fluotination, which is the best method of preparation, are shown ki equations 1—3. 

CH-bonds for anodic substitution can be those in alkanes and aryl compounds as well as those activated by an aryl, alkoxy, thio, amino group, or a double bond. 

Aus Thiophosphorsaure-0,0-diester-isocyanaten werden mit Alkoholen bzw. Alkan-thiolen (207Diethylether) Thiophosphorsaure-alkoxycarbonylamid- bzw. -(alkyl-thio-carbonyl)-amid-0,0-diester (80—99%) erhalten433 ... 

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