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。