triethylamine-bonded sulfonic acid {[et3n-so3h]cl} as an efficient and homogeneous catalyst for the synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-ones

[ ' b r ø n s t e d a c i d i c i o n i c l i q u i d ' , ' t r i e t h y l a m i n e ' , ' b o n d e d s u l f o n i c a c i d { [ e t 3 n ' , ' s o 3 h ] c l } ' , 1 2 , ' a r y l ' , 8 , 9 , 1 0 , 1 2 , ' t e t r a h y d r o b e n z o [ a ] x a n t h e n ' , 1 1 , ' o n e ' , 2 , ' n a p h t h o l ' , ' a r y l a l d e h y d e ' , ' d i m e d o n e ( 5 ' , 5 , ' d i m e t h y l c y c l o h e x a n e ' , 1 , 3 , ' d i o n e ) ' ]