Jc. Henrion et al., CONDENSATION INDOLE NAPHTHOQUINONE - SYNT HESIS OF A NEW INDOLYL-1,4-NAPHTHOQUINONE SERIES/, Bulletin des Societes chimiques belges, 103(4), 1994, pp. 163-168
Addition of an indole, which does not have a group at the 3-position,
to 1,4-naphthoquinone leads to the expected 2-(3-indolyl)-1,4-naphthoq
uinone. When the 1,4-naphthoquinone is substituted at the 2-position b
y an alkyl or aryl group, the e-substituted 3-(3-indolyl)-1,4-naphthoq
uinone is easily formed. However, when the e-substituent of the quinon
e is functional (OH, OMe, Cl, Br, NC5H10, S-C6H5), in addition to the
new series of expected indolylnaphthoquinones, several by-products res
ulting from elimination of the 2-substituted and/or further reaction o
f these compounds are formed. The outcome at the reaction appears to b
e very sensitive to the experimental conditions.