The present invention relates to a process for preparing a-lithio derivatives of the general formula:
wherein R' and R", which may be the same or different, each represent a hydrogen atom, an alkyl, alkoxyalkyl, dialkylaminoalkyl, aralkyl, alkoxy or dialkylamino group, or a monocyclic aryl ring optionally substituted by one or more alkyl, alkoxy, dialkylamino or monocyclic aryl groups and M represents an alkali metal atom, and to their use. In the process of the invention an acid of the general formula:
wherein R' and R" are as defined above or a salt thereof is reacted with lithium and a dialkylamine in the presence of an aromatic polynuclear hydrocarbon or an unsaturated hydrocarbon comprising an aliphatic or alicyclic chain containing a double bond conjugated either with a second double bond in the chain or with an aromatic moiety. The reactants are brought together so that there is substantially no lithium dialkylamide formed before the acid is introduced.
The thus formed derivatives can be reacted with a compound A-X where A is an alkyl or alkenyl group and X is halogen or -O-SO2-R3 where R' is alkyl or aryl to form an acid of the general formula:
where R' and R" are as defined above.
本发明涉及一种制备通式为 a-
硫代衍
生物的工艺:
其中R'和R "可以相同或不同,各自代表氢原子、烷基、烷氧基烷基、二烷基
氨基烷基、芳基、烷氧基或二烷基
氨基基团,或任选被一个或多个烷基、烷氧基、二烷基
氨基或单环芳基取代的单环芳基环,M代表碱
金属原子,以及它们的用途。在本发明的工艺中,通式为
其中 R' 和 R "如上定义或其盐与
锂和二烷基胺在芳香族多核烃类或不饱和烃类的存在下反应。将反应物混合在一起,以便在引入酸之前基本上不形成二烷基酰胺
锂。
由此形成的衍
生物可与化合物 A-X 反应,其中 A 为烷基或烯基,X 为卤素或-O-SO2-R3,其中 R' 为烷基或芳基,形成通式如下的酸:
其中 R' 和 R" 如上定义。