申请人:Ciba-Geigy Corporation
公开号:US04692524A1
公开(公告)日:1987-09-08
The present invention relates to a process for the preparation of 2-mercapto-4,6-bis-fluoroalkoxypyrimidines of the formula ##STR1## wherein R.sub.1 is C.sub.1 -C.sub.4 alkyl, phenyl or benzyl and each of T.sub.1 and T.sub.2 independently of the other is hydrogen or a --CHX.sub.1 X.sub.2 group, wherein each of X.sub.1 and X.sub.2 independently of the other is trifluoromethyl, fluorine, chlorine or bromine. In accordance with this process, 2-mercapto-4-halo-6-hydroxy-pyrimidines of the formula ##STR2## wherein R.sub.1 is as defined above and Y is chlorine or bromine, are reacted with chlorodifluoromethane or a 1,1-difluoroalkene of the formula ##STR3## wherein each of the X.sub.1 and X.sub.2 independently of the other is trifluoromethyl, fluorine, chlorine or bromine, in an inert solvent and in the presence of a strong base, to give a 2-mercapto-4-halo-6-fluoro-alkoxypyrimidine of the formula ##STR4## wherein R.sub.1, Y and T.sub.1 are as defined above, said 2-mercapto-4-halo-6-fluoroalkoxypyrimidine is converted by subsequent reaction with an alkali metal nitrite or an alkaline earth metal nitrite into a 2-mercapto-4-hydroxy-6-fluoroalkoxypyrimidine of the formula ##STR5## wherein R.sub.1 and T.sub.1 are as defined above, and then said 2-mercapto-4-hydroxy-6-fluoroalkoxypyrimidine is converted by reaction with chlorodifluoromethane or a 1,1-difluoroalkene of the above formula into a 2-mercapto-4,6-bix-fluoroalkoxypyrimidine of the above formula. The 2-mercapto-4,6-bis-fluoroalkoxypyrimidines of the above formula are intermediates for the preparation of herbicidally effective sulfonylureas.
本发明涉及一种制备式为##STR1##的2-巯基-4,6-双(氟烷氧基)嘧啶的方法,其中R.sub.1是C.sub.1-C.sub.4烷基、苯基或苄基,T.sub.1和T.sub.2各自独立地是氢或--CHX.sub.1 X.sub.2基团,其中X.sub.1和X.sub.2各自独立地是三氟甲基、氟、氯或溴。根据该方法,式为##STR2##的2-巯基-4-卤代-6-羟基嘧啶(其中R.sub.1如上所定义,Y是氯或溴)与氯二氟甲烷或式为##STR3##的1,1-二氟烯(其中X.sub.1和X.sub.2各自独立地是三氟甲基、氟、氯或溴)在惰性溶剂和强碱存在下反应,得到式为##STR4##的2-巯基-4-卤代-6-氟烷氧基嘧啶(其中R.sub.1、Y和T.sub.1如上所定义)。该2-巯基-4-卤代-6-氟烷氧基嘧啶通过随后与碱金属亚硝酸盐或碱土金属亚硝酸盐的反应转化为式为##STR5##的2-巯基-4-羟基-6-氟烷氧基嘧啶(其中R.sub.1和T.sub.1如上所定义),然后该2-巯基-4-羟基-6-氟烷氧基嘧啶通过与氯二氟甲烷或上述式的1,1-二氟烯的反应转化为式为上述式的2-巯基-4,6-双(氟烷氧基)嘧啶。上述式的2-巯基-4,6-双(氟烷氧基)嘧啶是制备除草剂有效的磺酰脲的中间体。