Spirolactones of xanthene. IV New method of xanthone synthesis by oxidation of novel spirolactones of dibenzo[c,h]xanthene and xanthenes.

Abstract

Dibenzo [c,h]xanthone and halogen-and methyl-substituted xanthones have been synthesized by the oxidation of novel spirolactones of dibenzo[c,h]xanthene and xanthene , which were prepared by a new condensation reaction of l-naphthol or phenol derivatives with oxalic acid in the presence of sulfuric acid. The oxidation was carried out by using potassium permanganate in the presence of aqueous potassium hydroxide. The dibenzo [c,h]xanthone and xanthones were identical with samples obtained by another synthetic route.

4-Ferrocenylphenyl-Substituted Tritylium Dyes with Open and Interlinked C+Ar2Entities: Redox Behavior, Electrochromism, and a Quantitative Study of the Dimerization of Their Neutral Radicals

“…Complexes 1 + – 7 + were synthesized by two-step procedures involving the nucleophilic addition of 4-ferrocenylphenyllithium to the respective ketone and subsequent protolytic dehydration of the resulting carbinols 1-OH – 7-OH with Brookhart’s acid [H­(OEt 2 ) 2 ] + [B­{C 6 H 3 (CF 3 ) 2 -3,5} 4 ] − , which is subsequently denoted as BAr F 24 – . The required ketones were either obtained from commercial sources or prepared according to literature-known procedures. − 3,6-Dimethyl-9 H -thioxanthen-9-one ( 10 ) was prepared in a three-step synthesis in a manner largely analogous to that for similar thioxanthen-9-one derivatives, as detailed in the Experimental Section …”

“…3,6-Dimethylxanthen-9-one was prepared according to a three-step literature procedure. 42 For a batch size of 0.58 mmol, a yield of 208 mg (0.43 mmol, 88%) was obtained. 5-OH.…”