238
WILLIAM
[CONTRIBUTION FROM
THE
s. GUMPAND JAMES c
VOl. 67
VITUCCI
RESEARCH LABORATORIES OF O~~AUDAN-DELAWANNA, INC.]
2-Hydroxyphenyl Sulfoxides and 2-Hydroxyphenyl Sulfones BY
WIL~IAX s. GUMP AND JAMES
The l k e r a t u e contains several references to 2hydroxyphenyl sulfoxides's2 and sulfones. However, our knowledge in this field is quite fragmentary and the purpose of this investigation was to prepare a series of compounds in each group. Of particular interest is the synthesis of the yet unknown d-hydroxyphenyl sulfoxide and 2-hydroxyphenyl sulfones containing halogen substituents; 2-Hydroxyphenyl sulfone itself was synthesized bv Tassinaria who thought, however, that he had-prepared the 3-isomer- By the reaction of 4-bromophetiol with sulfur dichloride, Tassinari obtained 5-bromo-2-hydroxyphenyl sulfide (I) which he debrominated with zinc dust in alkaline solution. The resulting 2-hydroxyphenyl sulfide (11) was acetylated, oxidized by means of potassium permanganate and saponified to the sulfone (111) of the m. p. 186-187'. 3,416,6
OH
Br
OH
I
OH
OH
OH
OH
Br
I11
I1 OH
OH
IV
OH
OH
v
Mauthner4 synthesized 2-hydroxyphenyl sulfide by a different method, but proceeded from the sulfide to the sulfone in the same manner as Tassinari. However, Mauthner's melting points were wrong and Machek and Haas6 correcting his data stated that Mauthner had apparently obtained mixtures on account of incomplete oxidation and that 2-hydroxyphenylsulfone and 2acetoxyphenyl sulfone melt a t 191' and 186188', respectively, instead of 166165' and 147148' which Mauthner reported. We prepared the sulfone in good yield and purity by direct oxidation of 2-hydroxyphenyl sulfide with hydrogen peroxide in acetic acid solution; our melting points (cor.) 190-191' bot'h for the sulfone and its diacetate, are in general agreement with Machek and Haas and with Tassinari. Attention might also be called to discrepancies in the literature concerning 5-methyl-2-hydroxy(1) S. Smiles and R. LeRossignol, J . Chcm. Soc., 98, 745 (1908). ( 2 ) M.Gazdar and S. Smiles, ibid., 97, 2248 (1910). (3) G. Tassinari. Caer. chim. i f a l . , (a) 17, 90 jlSSi1; (b) 19, 313 1889). (4) F. Mauthner, B e y . , SS, 1351 (1906). ( 5 ) J. Zehenter and 0. Ripl, J . p m k l . Chcm., 199, 309 ( 1 0 3 - I ~ ( 6 ) G Machek and H. H a a s , zhi,i.. 160,4 1 (1942).
c. VlTUCCr
phenyl sulfide. Tassinari" obtained this s d d e from p-cresol and sulfur dichloride, believing, as in similar condensations, that he had the 3-isomer, and reporting a m. p. of 117-118'. Gazdar and Smiles2 reduced 5-methyl-2-hydroxyphenylsulfoxide to the sulfide and reported a m. p. of 143'. We found a m. p. of 114-115' for 5-methyl-2hydroxyphenyl sulfide, prepared by either Tassinari's or Gazdar and Smiles' methods. Tassinari3bhad also prepared 5-methyl-2-acetoxyphenyl sulfide, melting a t 83-84', whereas we found a m. p. of 126-127'. Oxidation of this substance gave 5-methyl-2-acetoxyphenyl sulfone, m. p. 212-213' (Tassinari, 206-208'; Heppenstd and smile^,^ 211'). 2-Hydroxyphenyl sulfoxide (IV) has not been previously described. One might conjecture that Xauthner's substances of the m. p. 164-165' and 147-148' represented the sulfoxide and its diacetate, but such is not the case. The direct oxidation of 2-hydroxyphenyl sulfide (11) with the theoretical amount of hydrogen peroxide or oi the diacetate by means of potassium permanganate or chromic acid resulted in mixtures from which the pure sulfoxide could not be isolated. Therefore, an indirect method was sought. Condensation of 4-bromophenol with thionyl chloride to 5-bromo-2-hydroxyphenyl sulfoxide (I) and debromination of the latter substance to 2-hydroxxphenyl sulfoxide ( I V ) with zinc dust in potassium hydroxide solution proved satisfacto?. It is interesting to note that zinc and alkali remove the bromine and leave the sulfoxide g o u p unchanged, whereas zinc and acetic acid act just in the opposite manner, the bromine being retained and the sulfoxide (V) reduced to the sulfide (I). 2-Hydroxyphenyl sulfoxide (IV) can be reduced readily with zinc and acetic acid to the corresporiding sulfide ( I I ) , arid oxidized to tht. SUIfone (111) with hydrogen peroxide. I t may be mentioned that ?-hydroxyphenyl sulfoxide dissolves in concd. sulfuric acid with a deep-blue color which is characteristic for sulfoxides.2 Substituted %-hydroxyphenyl sulloxides were synthesized by the reaction of p-substituted plienols having a t least one free o-position with thionyl chloride in the presence of aluminum chloride or by careful oxidation of the substituted sulfides by means of one mole of hydrogen peroxide. 2,4,5-Trichlorophenol did not condense with thionyl chloride; however, B,S,Cj-trichloro2-liydroxyphenyl sulfoxide was obtained readily bls hydrogen peroxide oxidation of the corresponding sulfide. KO further oxidation of the sulfoxide 7
\I
iicppenst i l l Inri
%
