An improved synthesis of the alkaloid Luotonin-A employing ionic liquid and water as key solvents

Luotonin A is among the first known natural product possessing the heteroaromatic pyrroloquinazoline ring system. Although many syntheses have been reported for this compound, but they all have one or the other draw back such as a large number of steps, use of hazardous reagents like sodium hydride, low temperature reactions, and lengthy reaction time. Herein we report the synthesis of luotonin A achieved in five steps in which, two of the steps involved green solvents such as an ionic liquid and water as reaction media. In particular, we have achieved the reaction steps 1 and 3 involving the green solvents in much shorter reaction time than hitherto reported.