1,1-(Thiadialkylidene) ferrocene S-oxides

DETAILED DESCRIPTION The novel compounds of the present invention may be represented by the following formulae: ##SPC1## ##SPC2## Wherein R.
sub.
1, R.
sub.
2, R.
sub.
3 and R.
sub.
4 are selected from the group consisting of hydrogen, lower alkyl such as methyl, ethyl, isopropyl, butyl and hexyl, an aryl such as phenyl, or a nuclear-substituted phenyl such as halogen-substituted phenyl, an aralkyl such as benzyl, phenethyl, phenylisopropyl, diphenylmethyl, a cycloalkyl, particularly a cycloalkyl having from 3 to 7 carbon atoms such as cyclopropyl, cyclopentyl, cyclohexyl and a cycloalkyl-lower alkyl such as cyclohexylmethyl and cyclopentylethyl.
The novel compounds of Formula I, the S-dioxides, are conveniently prepared by treating a corresponding ferrocene cyclic thioether with a suitable oxidizing agent in acetone.
The preferred oxidizing agent is 30 percent hydrogen peroxide solution, but other oxidizing agents such as m-chloroperbenzoic acid, peracetic acid or permanganate may be used.
The reaction is preferably conducted under reflux conditions and is essentially complete after about 7 to 9 hours.
The compounds of Formula II, the S-mono-oxides, are conveniently prepared by the same reaction except that the reaction is interrupted after about only two to three hours at reflux or at any other point at which is can be established that the formation of the S-mono-oxides is essentially complete and that significant formation of the S-dioxides has not occurred.
The described processes may be illustrated as follows: ##SPC3## In which R.
sub.
1, R.
sub.
2, R.
sub.
3 and R.
sub.
4 are as previously defined.
Representative of the compounds which may be prepared by the described processes are the following: 1,1 '-dimethyl-.
alpha.
,.
alpha.
'-thiabiscyclopentadienyl-iron-S-oxide, 1,1'-dimethyl-.
alpha.
,.
alpha.
'-thiabiscyclopentadienyl-iron-S-dioxide, 1,1'-diethyl-.
alpha.
,.
alpha.
'-thiabiscyclopentadienyl-iron-S-oxide, 1,1'-diethyl-.
alpha.
,.
alpha.
'-thiabiscyclopentadienyl-iron-S-dioxide, 1,1'-dipropyl-.
alpha.
,