GB825760A - New hydroquinone compounds and process for their manufacture - Google Patents

Abstract

The invention comprises compounds of the formula <FORM:0825760/IV (b)/1> wherein R1 and R2 are alkoxy or alkylmercapto groups, the alkyl groups of which contain 1-4 carbon atoms, and salts of these compounds. The compounds are made by treating the corresponding quinone with a reducing agent, for example sodium dithionite in alkaline solution or hydrogen in the presence of a nickel catalyst. The reduction is suitably carried out in the absence of oxygen, for example in an atmosphere of hydrogen or nitrogen. If desired, the starting materials may be formed in the course of the reaction. For example, quinones wherein R1 and R2 are exchangeable substituents such as halogen atoms, can be treated with an excess of a lower alkyl mercaptan, preferably in the presence of an alkali-metal. In examples: (1) 3:6 - diethoxy - 2:5 - bis - ethyleneimino - p - benzoquinone is hydrogenated in the presence of Raney nickel to give 3:6-diethoxy-2:5-bis-ethyleneimino hydroquinone; (2) 3:6-dichloro-2:5 - bis - ethyleneimino - p - benzoquinone is treated with methyl mercaptan in the presence of metallic sodium and the reaction mixture is treated with sodium dithioxide in alkaline solution to complete reduction to 3:6-bis-methyl-mercapto - 2:5 - bis - ethyleneimino - hydroquinone; (3) 3:6 - dichloro - 2:5 - bis - ethyleneimino - p - benzoquinone is treated with an excess of methyl mercaptan in the presence of sodium to give the product of (2); (4) 3:6-dichloro-2:5-bis-ethyleneimino-p-benzoquinone is treated with an excess of ethyl mercaptan in the presence of sodium to give 3:6-bis-ethylmercapto - 2:5 - bis - ethyleneimino - hydroquinone; (5) 3:6-diethoxy-2:5-bis-ethyleneimino-p-benzoquinone is reduced with sodium dithionite to 3:6-diethoxy-2:5-bis-ethyleneimino-hydroquinone; and (6) the product of (1) is converted into its disodium salt.