抄録
1-Methyl-2-ethoky-, 2-ethoxy- and 3-methoxy-indoles (I, II, and III) were applied to some N-oxides of pyridine series in the presence of an acylating agent. The reaction. of I with quinoline 1-oxide (IV) in the presence of tosyl chloride or benzoyl chloride progressed in the cold, and 1-methyl-2-ethoxy-3-(2-quinolyl) indole (V) was obtained in good yields. The reaction under heating was prone to afford the oxindole derivative (VI), the total yield being decreased. Not only 2-chloro- and 4-chloroquinoline 1-oxides (X and XIII) but also pyridine and 4-chloropyridine 1-oxides (XXII and XXVII) were shown to react similarly with I in the presence of tosyl chloride to give the corresponding 3-substituted indoles, XI, XIV, XXIII, and XXVIII, respectively.
Similar reaction of II with IV yielded 2-ethoxy-3-(2-quinolyl) indole (XXX).
The reaction of III with IV or ethyl nicotinate 1-oxide (XLIII) led to the formation of 2-substituted-3-methoxy-indoles (XXXIII and XLIV), although the yield of XLIV was very poor.
The mechanism of the reductive de-ethoxylation of 2-ethoxy-3-(2-quinolyl or 2-pyridyl) indoles (V, XIV, XXX, and XXIII) by lithium aluminium hydride was discussed.
