Sequential four-component synthesis of spiro[chromene-indolo[۲,۱-b]quinazoline] and spiro[indolo[۲,۱-b]quinazoline-pyrano[۳,۲-c]chromene]

This work reports a rapid and straightforward process for the transformations involving tryptanthrines, malononitrile, two types of CH-acids such as dimedone and ۴-hydroxycumarin leading to spiro[chromene-indolo[۲,۱-b]quinazoline] and spiro[indolo[۲,۱-b]quinazoline-pyrano[۳,۲-c]chromene] derivatives through sequential Knoevenagel/Michael/intramolecular cyclization sequences in CH۲Cl۲ at room temperature. This protocol benefits some notable advantages including mild reaction condition, short reaction time and simple purification, which make it interesting.

Keywords:

Isatin , Chromene , Indoloquinazoline , Pyrano[۳ , ۲-c]chromen , Spiro compound.