Trimethoxyboroxine102-24-9100 % similar Trimethyl borate121-43-767 % similar 2-Methoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane1195-66-042 % similar Boron trioxide1303-86-242 % similar Diethylmethoxyborane7397-46-832 % similar