The invention relates to a compound of formula Ia or Ib wherein R1 represents —CO2R3, —COR4 or —R5, wherein R3 represents unsubstituted or substituted C1-C6 alkyl, R4 represents hydrogen, unsubstituted or substituted C1-C6 alkyl, and R5 represents hydrogen, unsubstituted or substituted C1-C6 alkyl, R2 represents —N+(R6)(R7)(R8)X− or a nitro group, wherein R6, R7, R8 independently of each other represent unsubstituted or substituted C1-C6 alkyl or unsubstituted or substituted —(CH2)n- with n=1 to 12 provided that at least two of the substituents R6R7R8 are C1-C6 alkyl, and X− represents a halide, sulphonate, unsubstituted or substituted acetate, sulphate, hydrogen sulphate, nitrate, perchlorate, or oxalate.
本发明涉及式Ia或Ib的化合物,其中R1表示—CO2R3,—COR4或—R5,其中R3表示未取代或取代的C1-C6烷基,R4表示氢,未取代或取代的C1-C6烷基,R5表示氢,未取代或取代的C1-C6烷基,R2表示—N+(R6)(R7)(R8)X−或硝基基团,其中R6,R7,R8独立地表示未取代或取代的C1-C6烷基或未取代或取代的—(
CH2)n-,其中n = 1至12,前提是至少有两个取代基R6R7R8是C1-C6烷基,X−表示卤化物,
磺酸盐,未取代或取代的
醋酸盐,
硫酸盐,
氢硫酸盐,
硝酸盐,
高氯酸盐或
草酸盐。