A process for the preparation of a compound of formula (I) or a salt thereof
wherein
R is an amino, nitro or -NHCOR1 group, wherein R1 is C1-C6 alkyl or phenyl optionally substituted by a -O-(CH2)n-phenyl group, wherein n is an integer of 1 to 6; comprising reacting a compound of formula (II) or a salt thereof, both as the individual isomer and as an isomeric mixture,
wherein R is as defined above; with a dehydrating agent, if necessary in the presence of an organic solvent, and optionally in the presence of a basic agent; and, if desired, converting a compound of formula (I) to another compound of formula (I) or a salt thereof.
一种制备式(I)化合物或其盐的方法,其中R是
氨基,硝基或-NHCOR1基团,其中R1是C1-C6烷基或苯基,可以被-O-(
CH2)n-苯基基团取代,其中n是1至6的整数;包括将式(II)化合物或其盐,作为单个异构体和异构体混合物,其中R如上所定义,与脱
水剂反应,必要时在有机溶剂存在下,选配碱性剂;如果需要,将式(I)化合物转化为另一种式(I)化合物或其盐。