摘要 |
There are disclosed novel thiorhodamines having the following structural formula: <CHEM> wherein R and R1 are individually H or alkyl of 1 to 5 carbon atoms, and Z is an anion. Also disclosed is the only known, and novel, method for making them, namely a) conducting an addition reaction between a thioxanthone and a compound having the formula: <CHEM> wherein R2 is alkyl of 1 to 5 carbon atoms; b) dehydrating the resulting compound of step a) in a strong acid to form a 9-[2-oxazolinylphenyl]thioxanthylium salt; c) hydrolyzing the oxazoline ring with acid to the 9-(2-carboxyphenyl)thioxanthylium salt; and d) optionally esterifying the resultant compound of step c) in an alkanol and strong acid, wherein the alkanol contains from 1 to 5 carbon atoms. |