Ambroxol EP Impurity B Catalogue A253652 CAS 18683-95-9 M.W 390.12 M.F C14H18Br2N2O Specifications FAQs CAS:15942-08-2l(trans)-4-(6,8-dibromo-1,4-dihydroquinazolin-3(2H)-yl)cyclohexan-1-ol