A synthesis of 2-dihydroquinazolin-2-ylquinoline using a phase-transfer catalyst (TBAHS)
in semi-aqueous phase, followed by Mitsunobu cyclization as key steps for an efficient
and practical synthesis of naturally occurring alkaloids luotonin A, B, and E starting
from o-nitrobenzaldehyde is reported. The new approach presents the advantage of a shorter
route with high overall yield (57%, 45%, and 37%, respectively) and ease of operation.
Key words
luotonins - 2-dihydroquinazolin-2-ylquinoline - tetrabutylammonium hydrogen sulfate
(TBAHS) - Mitsunobu