TY - JOUR
T1 - Dimerizations of 2-bromo-3-methyl-1,4-naphthoquinone and 2-methyl-1,4-naphthoquinone in tetra-n-butylammonium bromide
AU - Onuki, Mai
AU - Ota, Motohiro
AU - Otokozawa, Shoya
AU - Kamo, Shogo
AU - Tomoshige, Shusuke
AU - Tsubaki, Kazunori
AU - Kuramochi, Kouji
N1 - Funding Information:
This study was supported by Japan Society for the Promotion of Science (JSPS) KAKENHI (No. 18K19185 ) and the Sumitomo Foundation (No. 170183 ) to K.K. Appendix A
Publisher Copyright:
© 2019 Elsevier Ltd
PY - 2020/2/7
Y1 - 2020/2/7
N2 - 2-Bromo-3-methyl-1,4-naphthoquinone and 2-methyl-1,4-naphthoquinone are highly reactive species known to dimerize in various ways. The product obtained in the dimerization of each compound is primarily dependent upon the solvent used. Ionic liquids represent a new class of solvents having non-molecular (ionic) character. Replacement of a conventional organic solvent with an ionic solvent frequently changes the mechanism of a reaction. In this study, reactions of 2-bromo-3-methyl-1,4-naphthoquinone and 2-methyl-1,4-naphthoquinone in ionic liquids were examined. Dimerization of 2-bromo-3-methyl-1,4-naphthoquinone or 2-methyl-1,4-naphthoquinone with N-methylcyclohexylamine in tetra-n-butylammonium bromide (TBAB), an ionic liquid, under an aerobic atmosphere afforded 5,7,12,14-pentacenetetrone and 1-methylKuQuinone, respectively. The use of TBAB as a solvent improved the yields of the products as compared with previously reported methods. The mechanism of each dimerization was also investigated.
AB - 2-Bromo-3-methyl-1,4-naphthoquinone and 2-methyl-1,4-naphthoquinone are highly reactive species known to dimerize in various ways. The product obtained in the dimerization of each compound is primarily dependent upon the solvent used. Ionic liquids represent a new class of solvents having non-molecular (ionic) character. Replacement of a conventional organic solvent with an ionic solvent frequently changes the mechanism of a reaction. In this study, reactions of 2-bromo-3-methyl-1,4-naphthoquinone and 2-methyl-1,4-naphthoquinone in ionic liquids were examined. Dimerization of 2-bromo-3-methyl-1,4-naphthoquinone or 2-methyl-1,4-naphthoquinone with N-methylcyclohexylamine in tetra-n-butylammonium bromide (TBAB), an ionic liquid, under an aerobic atmosphere afforded 5,7,12,14-pentacenetetrone and 1-methylKuQuinone, respectively. The use of TBAB as a solvent improved the yields of the products as compared with previously reported methods. The mechanism of each dimerization was also investigated.
KW - 1,4-Naphthoquinone
KW - 1-MethylKuQuinone
KW - 5,7,12,14-Pentacenetetrone
KW - Dimerization
KW - Ionic liquid
UR - http://www.scopus.com/inward/record.url?scp=85077151606&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85077151606&partnerID=8YFLogxK
U2 - 10.1016/j.tet.2019.130899
DO - 10.1016/j.tet.2019.130899
M3 - Article
AN - SCOPUS:85077151606
VL - 76
JO - Tetrahedron
JF - Tetrahedron
SN - 0040-4020
IS - 6
M1 - 130899
ER -