59007-07-7

Upstream product

• 148934-62-7 1-(2,5-dimethoxyphenyl)naphthalene 
• 107099-99-0 2,5-dimethoxyphenylboronic acid 
• 90-11-9 1-Bromonaphthalene 
• 178266-72-3 1-(2,5-dihydroxyphenyl)naphthalene 

Relevant academic research and scientific papers

Solvent-dependent excited state intramolecular proton transfer (ESIPT) pathways from phenol to carbon in 2,5-dihydroxyphenyl arenes

The ESIPT of three 2,5-dihydroxyphenyl-substituted arenes 9-11 was studied in various solvent systems, to investigate the direction of the proton transfer from the phenol to the respective carbons of naphthyl, phenanthrenyl and anthryl aromatic rings. In neat CH3CN, 9-11 undergo direct ESIPT from the phenolic OH to the ipso-position of the corresponding aromatic carbon acceptors, via an intramolecular charge transfer state (S1,ct), giving rise to observable zwitterions, ZIs 35, 25, 27, respectively. Surprisingly, the generated ZI in 9 proceeds via a 1,2-phenyl migration followed by re-aromatization to afford 16 (a structural isomer of 9) in quantitative yield. In 10 and 11, the corresponding ZIs proceed via electrocyclic ring closure to furnish 20 and 28, respectively. In the case of 10, another intrinsic ESIPT pathway takes place to the 10-position of a phenanthrenyl ring, giving QM 26 in high quantum efficiency (Φex = 0.72). In aqueous solution, 9 undergoes formal ESIPT to the more distal 2′- and 7′-positions of the naphthalene ring, delivering QMs 18 and 38, which either revert back to the starting material or proceed via electrocyclic ring closure, respectively. In 11 in aqueous solution, formal ESIPT to the 10-position of the anthracene ring takes place delivering QM 29, which readily aromatizes to regenerate starting material.

Novel access to cyclohexane-1,4-diones and 1,4-hydroquinones via radical 1,2-acyl rearrangement on 2-(halomethyl)cyclopentane-1,3-diones using cobaloxime-mediated electroreduction or tributyltin hydride

A new preparative access to synthetically useful cyclohexane-1,4-diones 2 and their oxidized analogues, hydroquinones 3, with the option of introducing alkyl and aryl substituents, was developed by radical 1,2-acyl rearrangement on 2-(halomethyl)cyclopentane-1,3-diones 1, accessible from 1,2-bis(trimethylsiloxy)cyclobutene and α-bromo ketone dimethyl acetals. The electroreduction of monoacetals of 1 in the presence of cobaloxime as a catalyst afforded the cyclohexane-1,4-dione monoacetals in good yields. The Bu3SnH-reduction of 2-aryl 1 under refluxing in benzene effected the rearrangement, affording 2, and when the reaction was prolonged, aromatization to 3 proceeded in moderate yields.