Process for brominating the side chain of 4-methylbiphenyl derivatives substituted in the 2' position
申请人:——
公开号:US20020095042A1
公开(公告)日:2002-07-18
A process for preparing 4-bromomethylbiphenyl derivatives substituted in the 2′ position of general formula (I)
1
by brominating 4-methylbiphenyl derivatives substituted in the 2′ position of general formula (II)
2
wherein:
R is CN, COOR
1,
CONR
1
R
2
, or C(OR
3
)═NR
4
, or 5-tetrazolyl optionally substituted by benzyl, methyloxycarbonyl, ethyloxycarbonyl,
9
-fluorenylmethyloxycarbonyl, 2,2,2-trichloroethyloxycarbonyl, benzyloxycarbonyl, tert-butyloxycarbonyl, allyloxycarbonyl, trichloroacetyl, trifluoroacetyl, or trityl;
R
1
and R
2
which are identical or different are hydrogen or C
1
-C
6
-alkyl;
R
3
and R
4
together are a C
2
-C
3
-alkylene bridge optionally mono-, di-, tri-, or tetra- substituted by one or more of the groups methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, phenyl, or naphthyl,
wherein the brominating is carried out by means of an N-bromoimide or N-bromoamide in a solvent of organic carboxylic acid esters.
一种制备2'位置取代的4-溴甲基联苯衍生物的方法,通过对2'位置取代的4-甲基联苯衍生物进行溴化,通式(I)为:其中:R为CN、COOR1、CONR1R2或C(OR3)HNR4,或者选择性地被苄基、甲氧羰基、乙氧羰基、9-芴甲氧羰基、2,2,2-三氯乙氧羰基、苄氧羰基、叔丁氧羰基、烯丙氧羰基、三氯乙酰基、三氟乙酰基或三苄基取代的5-四唑基;R1和R2相同或不同,为氢或C1-C6-烷基;R3和R4共同形成C2-C3烷基桥,可选择性地通过一个或多个甲基、乙基、正丙基、异丙基、正丁基、异丁基、叔丁基、苯基或萘基取代一次、二次、三次或四次,溴化通过有机羧酸酯溶剂中的N-溴代亚胺或N-溴代酰胺进行。