A Colorimetric Proton Sponge

1-8-Bis(dimethylammo)naphtlialene (Proton Sponge) and bromomaleic anhyride lean quickly at room temperature). generating 3-(4.5-bis(dimethylammo)napthalen-1-yl)furan-2.5-dione (4-maleicanhydndopioton sponge or MAPS) MAPS is a deep purple solid that exhibit positive solvato-chrormsin in solution. It is a weaker base than Proton Sponge When protona led in solution. MAPS loses us cohn but the color change can be reversed by deprotonation with a stronger base MAPS thus acts as a colorimetric version of a proton sponge