62750-57-6Relevant academic research and scientific papers
Dibenzocyclooctene-, Dibenzochalcocine-, and Diarenochalconinediones
Hellwinkel, Dieter,Bohnet, Siegbert
, p. 1151 - 1174 (2007/10/02)
2,2'-Oxybis-, -thiobis-, and -methylenebisbenzoic esters 2a-c react with methyllithium in ether to give low yields of 5H-dibenzochalcocine-5,7(6H)-diones 6a, 7a, and dibenzocyclooctene-5,7(6H,12H)-dione (8), respectively.Very good yields of such heterocycles with oxygen (6a-h, 37), sulfur (7a-h, 38) and selenium (36) as key atom are obtained when diaryl ethers (21, 22, 25), -sulfides (27, 29, 30), and -selenides (33) that contain 2'-acetyl- (or -propionyl-) and 2-methoxycarbonyl groups are treated with sodium hydride in boiling toluene.Analogously are prepared the dibenzoxonine-11,13(6H,12H)diones 62a-c and 7H-benzonaphthothionine-7,9-(8H)-dione (65) which are expanded by one ring member.In the analogous reaction of a corresponding benzophenone derivative 35, spiro-3(2H),3'-dione (41) is formed in a tandem reaction. - Under phase transfer conditions the dibenzochalcocinediones 6, 7, 36 and also the corresponding nitrogen cycles 5 react to give mixtures of C- (42-45) and O-alkyl derivatives (46-49).Methyllithium and diisobutylaluminium hydride provide the carbinols 50-54.With bromine and SO2Cl2, respectively, the methylene group is mono- or dihalogenated to the products 56, 57; defined nitration was only possible for the oxacycle 6a.
