Trimethoprim Impurity B

(2,4-diaminopyrimidin-5-yl)(3,4,5-trimethoxyphenyl)methanone|(2,4-Diaminopyrimidin-5-yl)(3,4,5-trimethoxyphenyl)methanone ;|(2,4-diaminopyrimidin-5-yl)(3,4,5-trimethoxyphenyl)methanone;|5-(3,4,5-Trimethoxybenzoyl)-2,4-pyrimidinediamine