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reaction vessel is closed and after each one-minute period the solution
is allowed to cool.
(c) Preparation of S-Methyl O-Phenyl Dithiocarbonate
To the resulting CS2 solution, which contains S-sodium O-phenyl
dithiocarbonate, 50 mmol of iodomethame is added and refluxed for 1 h
with stirring. The CS2 solvent is removed to obtain a white powder,
which is used without further purification.
(d) Preparation of Diphenyl Disulfide
S-methyl-O-phenyl dithiocarbonate is first rearranged to its isomer,
S-methyl-S-phenyl dithiocarbonate, by heating the white powder at
275◦C under nitrogen gas for 1 h. S-methyl-S-phenyl dithiocarbonate
is then hydrolyzed by adding 10% aqueous sodium hydroxide to a
cooled reaction mixture and is refluxing for 30 min. An addition
of dilute HCl converts the hydrolyzed product (C6H5SNa) to thio-
phenol. However, direct separation of thiophenol from this reaction
mixture is practically impossible. Therefore, it is first oxidized in
situ by trichloroisocyanuric19 acid in CH2Cl2 to diphenyl disulfide
(C6H5SSC6H5), which is then washed with 5% sodium hydroxide to
remove any trace of unreacted phenol. The solvent is removed to obtain
diphenyl disulfide as a white powder.
(e) Preparation of Thiophenol
The above diphenyl disulfide is reduced by zinc/acetic acid. Thiophe-
nol is then separated by conventional methods, the melting point and
spectral data of which are consistent with the reported ones. Yield: 42%.
Note 1: All steps are carried out in a good ventilated hood.
Note 2: Oxidation-reduction steps are not necessary for the con-
version of bisnaphthols to 14-aryl-14H-7-thiadibenzo[a, j]-
anthracenes.
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