An ultrasound assisted cyclocondensation reaction for the efficient synthesis of [1]benzopyranopyrido[d]pyrimidines using porous graphene/MoO₃

Abstract

In this paper, we report a feasible protocol for the preparation of [1]benzopyranopyrido[d]pyrimidines via expeditious sonochemical route. The reaction efficiency was evaluated by influence of several parameters including sonication power, sonication time, different solvents, and using porous graphene/MoO 3 nanocomposite as catalyst, for the first time. The effect of the ultrasonication comparing with the conventional heating on the synthesis of the titled compounds shows that the ultrasonic irradiation is required to rich the cyclized products. The structural properties of porous graphene/MoO 3 nanocomposite were determined by Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffractometry (XRD), scanning electron microscope (SEM), Raman spectroscopy, and also by TGA analysis. Confirmation of the structures of compounds 4a-4h were also established with IR, 1 H NMR, and 13 C NMR spectroscopic data and also by elemental analyses.

Greener organic synthetic methods: Sonochemistry and heterogeneous catalysis promoted multicomponent reactions

“… Entry Catalyst Conditions Examples Yields (%) Ref. 1 Ag@CDNS-SBA-15 H 2 O, 25–50 min, 55 °C 11 80–95 [189] 2 HPA@HNTs-C H 2 O, 4–22 min, r.t. 7 80–95 [190] 3 MoO 3 @porous graphene H 2 O,10–66 min, r.t. 8 95–98 [191] *Ultrasound parameters: Entry 1. Operating with a power of 125 W at a temperature of 55 °C and tip TT13, other ultrasound parameters were not mentioned.…”

“…Encouraged by the interest in greener synthetic routes for obtaining heterocycles, the Abdolmohammadi group [191] developed a successful method for synthesis of benzopyranopyrido[ d ]pyrimidines ( 1 0 7 ) via one-pot condensation of aldehydes ( 1 ), 6-amino-1,3-dimethyluracil ( 85 ) and 4-hydroxycoumarin ( 1 0 1 ), using a heterogeneous reusable catalyst of MoO 3 /NPs incorporated in porous biographene (MoO 3 @porous graphene, 0.4 w/w %) ( Table 10 , Entry 3). The reaction was performed using on a multiwave ultrasonic generator, equipped with a converter/transducer and titanium oscillator (horn), 12.5 mm in diameter, with an operation frequency of 20 kHz with a power output of 70 W. In the optimization study, the reaction was performed using conventional heating and the product of interest was not observed.…”