An Experimental and Theoretical Study of the 1,3-Dipolar Cyclo­addition of Alloxan-Derived Azomethine Ylides to Cyclopropenes

Abstract

A diastereoselective synthesis of biologically interesting spirobarbiturates has been achieved via [3 + 2] cycloaddition of alloxan-derived azomethine ylides to 3-R-1,2-diphenylcyclopropenes. With this approach, various spirobarbiturate-3-azabicyclo[3.1.0]hexanes and spirobarbiturate-cyclopropa[a]pyrrolizines were obtained in moderate to good yields with excellent diastereoselectivities. DFT calculations (M11 density functional theory) have been carried out to shed light on the molecular mechanism of 1,3-dipolar cycloaddition of alloxan-derived azomethine ylides to cyclopropenes. The cytotoxic activity of some obtained compounds against human erythroleukemia (K562) cell line was evaluated in vitro by MTS-assay.

Palladium-Catalyzed Oxidative Cycloaddition of Quinazoline-2,4(1H,3H)-diones and Diarylalkynes via C–H/N–H Activation

“…This work is a continuation of our research in the field of chemistry of quinazoline-2,4(1 H ,3 H )-diones. 17…”

“…This work is a continuation of our research in the field of chemistry of quinazoline-2,4(1H,3H)-diones. 17 We started the investigation by reacting 3phenylquinazoline-2,4(1H,3H)-dione (1a) with diphenylacetylene (2a) in the presence of different combinations of palladium catalysts and oxidants. In the presence of Pd(OAc) 2 or PdCl 2 and AgOAc as an oxidant in acetonitrile, the desired azepino[3,2,1-ij]quinazoline 3aa was formed in 67% and 54% yield, respectively (Table 1, entries 1 and 2).…”