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