TY - JOUR
T1 - Condensation reactions of indole with acetophenones affording mixtures of 3,3-(1-phenylethane-1,1-diyl)bis(1H-indoles) and 1,2,3,4-tetrahydro-3-(1H-indol-3-yl)-1-methyl-1,3-diphenylcyclopent[b]indoles
AU - Noland, Wayland E.
AU - Brown, Christopher D.
AU - DeKruif, Rodney D.
AU - Lanzatella, Nicholas P.
AU - Gao, Siming M.
AU - Zabronsky, Abigail E.
AU - Tritch, Kenneth J.
N1 - Funding Information:
The authors thank the Wayland E. Noland Research Fellowship Fund at the University of Minnesota Foundation for generous financial support of this project.
Publisher Copyright:
© 2018, © 2018 Taylor & Francis.
PY - 2018/7/18
Y1 - 2018/7/18
N2 - Condensation of indole 1a with eight acetophenones 8a–h in ethanolic HCl afforded the corresponding mixtures of condensation products: 3,3-(1-phenylethane-1,1-diyl)bis(1H-indoles) 11a–h (2:1 condensation of indole:acetophenone, –H2O) and diastereomers of substituted 1,2,3,4-tetrahydro-3-(1H-indol-3-yl)-1-methyl-1,3-diphenylcyclopent[b]indoles 12a–h and 13a–h (2:2 condensation of indole:acetophenone, –2H2O). Each mixture was analyzed by 1H NMR. The use of substituted electron-withdrawing acetophenones favored formation of 2:1 condensation products, whereas the use of substituted electron-donating acetophenones favored formation of 2:2 condensation products. Increased reaction temperature gave higher 2:2 condensation yields, but temperatures above 40 °C were unfavorable, giving complex, tarry mixtures.
AB - Condensation of indole 1a with eight acetophenones 8a–h in ethanolic HCl afforded the corresponding mixtures of condensation products: 3,3-(1-phenylethane-1,1-diyl)bis(1H-indoles) 11a–h (2:1 condensation of indole:acetophenone, –H2O) and diastereomers of substituted 1,2,3,4-tetrahydro-3-(1H-indol-3-yl)-1-methyl-1,3-diphenylcyclopent[b]indoles 12a–h and 13a–h (2:2 condensation of indole:acetophenone, –2H2O). Each mixture was analyzed by 1H NMR. The use of substituted electron-withdrawing acetophenones favored formation of 2:1 condensation products, whereas the use of substituted electron-donating acetophenones favored formation of 2:2 condensation products. Increased reaction temperature gave higher 2:2 condensation yields, but temperatures above 40 °C were unfavorable, giving complex, tarry mixtures.
KW - Acetophenones
KW - acid-catalyzed condensation
KW - bisindoles
KW - cyclopent[b]indoles
KW - indole
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U2 - 10.1080/00397911.2018.1460760
DO - 10.1080/00397911.2018.1460760
M3 - Article
AN - SCOPUS:85048360456
SN - 0039-7911
VL - 48
SP - 1755
EP - 1765
JO - Synthetic Communications
JF - Synthetic Communications
IS - 14
ER -