3,7 Diamino phenazine leuco dyes stabilized in the 10 position with acyl substituents, said acyl substituents being themselves substituted with {TAIL ~ electron} withdrawing {HEAD ~ groups} 
3,7 Diamino phenazine leuco dyes stabilized in the 10 position with acyl substituents , said acyl substituents being themselves substituted with { TAIL ~ electron } withdrawing { HEAD ~ groups }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD