DABCO Catalyzed Synthesis of Xanthene Derivatives in Aqueous Media.
The reaction of 5,5-dimethylcyclohexane-1,3-dione with various heteroarylaldehydes afforded the corresponding heteroaryl substituted xanthene derivatives 1(a-f). The reaction proceeds via the initial Knoevenagel, subsequent Michael, and final heterocyclization reactions using 1,4-diazabicyclo[2.2.2]octane (DABCO) as a catalyst in aqueous media. The synthesized heteroaryl substituted xanthenes 1(a-f) reacted with malononitrile to obtain different alkylidenes 2(a-f). Short reaction time, environmentally friendly procedure, avoiding of cumbersome apparatus, and excellent yields are the main advantages of this procedure which makes it more economic than the other conventional methods.
Laboratory of Heterocycles, School of Studies in Chemistry & Biochemistry, Vikram University, Ujjain, Madhya Pradesh 456010, India.
Pradeep
P
Paliwal
Srinivasa Rao
SR
Jetti
Anjna
A
Bhatewara
Tanuja
T
Kadre
Shubha
S
Jain