Multicomponent Dipolar Cycloaddition Strategy: Combinatorial Synthesis of Novel Spiro-Tethered Pyrazolo[3,4-b]quinoline Hybrid Heterocycles

Abstract

The stereoselective syntheses of a library of novel spiro-tethered pyrazolo[3,4-b]quinoline-pyrrolidine/pyrrolothiazole/indolizine-oxindole/acenaphthene hybrid heterocycles have been achieved through the 1,3-dipolar cycloaddition of azomethine ylides generated in situ from α-amino acids and 1,2-diketones to dipolarophiles derived from pyrazolo[3,4-b]quinoline derivatives.

Synthesis of pyrazolopyridine and pyrazoloquinoline derivatives by one-pot, three-component reactions of arylglyoxals, 3-methyl-1-aryl-1H-pyrazol-5-amines and cyclic 1,3-dicarbonyl compounds in the presence of tetrapropylammonium bromide

“…White solid; yield 95% (322 mg); mp: 144-146°C (lit. [22], 148-149°C); IR (KBr, cm - (24), 241 (14), 214 (10), 139 (36), 111 (19), 77 (32), 51 (10). Chlorophenyl)-3-methylindeno[1,2-b]pyrazolo[4,3-e…”

Crystal structure of 7′-(4-chlorophenyl)-2′′-(4-methoxyphenyl)-7′,7a',7′′,8′′-tetrahydro-1′H,3′H,5′′H-dispiro[indoline-3,5′-pyrrolo[1,2-c]thiazole-6′,6′′-quinoline]-2,5′′-dione and an unknown solvent

“…Three compounds closely resemble the title compound, viz. 4 0 -(4-chlorophenyl)-1 0 -methyl-3,4-dihydro-1H-dispiro[acridine-2,3 0 -pyrrolidine-2 0 ,3 00 -indole]-1,2 00 (1 00 H)-dione methanol solvate (CSD refcode NAQCAL; Maheswari et al, 2012), 4 0 -(2,4-dichlorophenyl)-10,3 00 -dimethyl-1 00 -phenyl-7 00 ,8 00 -dihydrodispiro[indole-3,2 0 -pyrrolidine-3 0 ,6 00 -pyrazolo[3,4-b]quinoline]-2,5 00 (1H,1 00 H)-dione chloroform solvate (UQIROD; Sumesh et al, 2016), and 4 0 -(2-chlorophenyl)-1 0 -methyl-2 00phenyl-7 00 ,8 00 -dihydro-5 00 H-dispiro[indoline-3,2 0 -pyrrolidine-3 0 ,6 00 -quinoline]-2,5 00 -dione (KEWKAB; Vishnupriya et al, 2018). Three other compounds contain a pyrrolothiazole moiety; they are the dispiro[cyclohexane-pyrrolothiazoleindole]-dione derivatives RAGMUK, RAGNAR and RAHBIO (Lotfy et al, 2017).…”

Crystal structure and Hirshfeld surface analysis of 4′-(2-chlorophenyl)-1′-methyl-3′′-phenyl-7′′,8′′-dihydro-5′′H-dispiro[indoline-3,2′-pyrrolidine-3′,6′′-isoquinoline]-2,5′′-dione

“…The intramolecular C-HÁ Á ÁO contacts (see Table 1) are shown as dashed lines. (CSD refcode NAQCAL: Maheswari et al, 2012), and 4 0 -(2,4dichlorophenyl)-1 0 ,3 00 -dimethyl-1 00 -phenyl-7 00 ,8 00 -dihydrodispiro[indole-3,2 0 -pyrrolidine-3 0 ,6 00 -pyrazolo[3,4-b]quinoline]-2,5 00 (1H,1 00 H)-dione chloroform solvate (UQIROD; Sumesh et al, 2016). In both compounds, the mean plane of the 1-methylpyrrolidine ring was found to be almost perpendicular to the mean plane of the indoline ring system and the mean plane of the cyclohexanone ring, similar to the situation in the title compound, see Section 2 Structural commentary.…”