Pyrazolo-fused 4-azafluorenones as key reagents for the synthesis of fluorescent dicyanovinylidene-substituted derivatives.

A green process to access pyrazolo-fused 4-azafluorenones (indeno[1,2-b]pyrazolo[4,3-e]pyridines, IPP) 4a-xvia the three-component reaction between indan-1,3-dione (1), benzaldehydes 2 and 5-amino-1-arylpyrazoles 3 is described. These compounds were successfully used as precursors of the novel dicyanovinylidene derivatives 7a-d containing different acceptor (A) or donor (D) aryl groups at position 4 of its fused system. The structures of products obtained (4a-x and 7a-d) were determined based on NMR experiments, HRMS analysis, and X-ray diffraction studies for 7b. The photophysical and computational studies of 7a-d showed that these products are modulable ICT fluorophores, even some preliminary tests revealed that these compounds could be used as fluorescent chemodosimeters for cyanide detection.

A π-stacked chain of hydrogen-bonded dimers in 3-tert-butyl-1-(4-chlorophenyl)-4-phenylindeno[1,2-b]pyrazolo[4,3-e]pyridin-5(1H)-one and a π-stacked sheet of hydrogen-bonded chains in 3-tert-butyl-1-(4-chlorophenyl)-4-(4-methoxyphenyl)indeno[1,2-b]pyrazolo[4,3-e]pyridin-5(1H)-one.

In 3-tert-butyl-1-(4-chlorophenyl)-4-phenylindeno[1,2-b]pyrazolo[4,3-e]pyridin-5(1H)-one, C(29)H(22)ClN(3)O, (I), inversion-related pairs of molecules are linked by C-H...O hydrogen bonds to form R(2)(2)(18) dimers, which are themselves linked into a chain by a π-π stacking interaction between inversion-related pairs of molecules. In 3-tert-butyl-1-(4-chlorophenyl)-4-(4-methoxyphenyl)indeno[1,2-b]pyrazolo[4,3-e]pyridin-5(1H)-one, C(30)H(24)ClN(3)O(2), (II), which crystallizes in the space group P-1, with Z' = 2 and with different orientations for the methoxy groups in the two independent molecules, a combination of C-H···O and C-H···π(arene) hydrogen bonds links the molecules into chains of rings, which are further linked into sheets by a π-π stacking interaction.

Synthesis of new indeno[1,2-e]pyrimido[4,5-b][1,4]diazepine-5,11-diones as potential antitumor agents.

Novel racemic indeno[1,2-e]pyrimido[4,5-b][1,4]diazepine-5,11-diones 3-29 were obtained regioselectivily from the reaction of 5,6-diamino-3,4-dihydropyrimidin-4-ones 1 and 2-arylideneindandiones 2 as reagents. These compounds have been evaluated at the US National Cancer Institute (NCI) for their ability to inhibit approximately 60 different human tumor cell lines, where 5 and 6 presented remarkable activity against 57 and 48 cancer cell lines, respectively, with the most important GI(50) values ranging from 0.49 to 1.46 microM, in vitro assay.