GB544849A - Improvements in the manufacture of aromatic compounds containing sulphur - Google Patents

Abstract

544,849. Aromatic, sulphones. MANCHESTER OXIDE CO., Ltd., CLAYTON, J. H., and BANN, B. Sept. 27, 1940, No. 14615. [Class 2 (iii)] Sulphones of the general formula wherein R and R<SP>1</SP> represent alkyl, substituted alkyl (including aralkyl) or aryl groups and the benzene ring may carry substituents or condensed nuclei, are obtained from the corresponding p-alkoxy-, p-aralkoxy- or p-aryloxyderivatives of thiocyanobenzene by the steps of (a) reducing the thiocyano group to the mercapto group, (b) converting the mercapto group into the thioether group by treatment with an etherifying agent, and (c) oxidizing the product. Alternatively, the starting-material may bep-thiocyanophenol or a derivative thereof (obtainable by the process of Specification 514,203), the phenolic OH group being etherified at any stage prior to the oxidation. The preferred oxidizing agent is an alkali metal permanganate in an aqueous medium, preferably containing acetic acid. The sulphones may be converted into the m-amino derivatives by nitration and reduction of the nitro group. Examples relate to the production of (1) pmethoxyphenyl-ethyl sulphone from p-thiocyanophenol by methylating the phenolic group by treatment with dimethyl sulphate and subjecting the product to the successive steps of (a) treatment with sodium sulphide in alcohol to replace the thiocyano by the mercapto group (b) ethylating the mercapto group by treatment with diethyl sulphate, and (c) oxidizing the product with potassium permanganate in aqueous acetic acid ; the product may be converted into 3-amino-4-methoxyphenyl ethyl sulphone by nitration and reduction of the nitro group with iron and acetic acid ; from the appropriate derivatives of p-thiocyanophenol may be similarly obtained the 5- or 6-methyl- or methoxyl- and 2:6- dimethylderivatives of 3-amino-4-methoxyphenyl ethyl sulphone, 3-amino-5-methyl-4- ethoxyphenyl methyl sulphone and 3-amino- 4:5-dimethoxyphenyl butyl sulphone ; (2) 3- methyl-4-ethoxyphenyl ethyl sulphone from 2-methyl-4-thiocyanophenol by the successive steps of (a) treatment with sodium sulphide in alcohol to replace the thiocyano by the mercapto group, (b) ethylating the phenolic and mercapto groups by treatment with diethyl sulphate, and (c) oxidizing the product as in (1) ; the product may be converted into 3-amino-5-methyl-4- ethoxyphenyl ethyl sulphone by nitration and reduction of the nitro group ; (3) 2<SP>1</SP>-nitro-4- methoxydiphenyl sulphone from p-thiocyanoanisole by the successive steps of (a) treatment with sodium sulphide in alcohol to replace the thiocyano by the mercapto group, (b) treatment with o-chloronitrobenzene to etherify the mercapto group, and (c) oxidizing the product as in (1) ; the nitro group may be reduced with tin and hydrochloric acid to obtain the 21- amino compound ; (4) 2<SP>1</SP>:4<SP>1</SP>-dinitro-3-methyl-4- methoxydiphenyl sulphone similarly from 2- methyl-4-thiocyanoanisole with the use of 2:4- dinitro-chlorobenzene as the etherifying agent; the 21-amino-41-nitro compound may be obtained by reducing the product with ammonium sulphide.