Patent ID: 6960668

Claim:
A process for the production of thioxanthone derivatives of the general formula (I) given below: where: R 1 , R 2 and R 3 is hydrogen, C 1 -C 10 alkyl, C 1 -C 10 alkoxy, halogen, hydroxy or C 1 -C 2 dialkylamino; R 1 , R 2 and R 3 being the same or different; R 4 is oxygen, sulphur or absent; R 5 is hydrogen, C 1 -C 10 alkyl or aryl; and R 6 is a straight or branched alkyl chain having 0 to 10 carbon atoms; the one-step process comprising reacting a compound of the general formula (II) below with mercaptobenzoic acid or dithiobisbenzoic acid in the presence of sulphuric acid: