Tetracyanoquinodimethane1518-16-7100 % similar 4-Dicyanomethylene-2,6-dimethyl-4H-pyran28286-88-644 % similar Isopropylidenemalononitrile13166-10-440 % similar [(Dimethylamino)methylene]propanedinitrile16849-88-033 % similar 2-Amino-1-propene-1,1,3-tricarbonitrile868-54-232 % similar