Reaction of 5,6‐dihydro‐4H‐pyrrolo[3,2,1‐ij]quinoline‐1,2‐dione (3) with two equivalents of cyclic 1,3‐dicarbonyl compounds under acid catalysis generates spiro[4H‐pyran‐3,3′‐oxindoles] 7. In contrast, though base catalysis also achieves double addition, the final products 8 result from subsequent ring opening of the five‐membered lactam via intramolecular attack by enolate; these products can be converted into the spiro[4H‐pyran‐3,3′‐oxindoles] by treatment with acid.
in Wiley InterScience (www.interscience.wiley.com).5-Hydrazinoquinoline and 8-hydrazinoquinoline were converted via Fischer syntheses with 3-methylbutan-2-one into pyrido-indolenines 2,3,3-trimethyl-3H-pyrrolo[2,3-f]quinoline 7 and 2,3,3-trimethyl-3H-pyrrolo[3,2-h]quinoline 11, respectively. Exposure of the indolenines to the Vilsmeier reagent produced aminomethylene-malondialdehydes 8 and 12, which reacted with hydrazine or arylhydrazines to give 4-(3H-pyrrolo[2,3-f]quinolin-2-yl)-and 4-(3H-pyrrolo[3,2-h]quinolin-2-yl)-pyrazoles, 9 and 13.
This paper is dedicated to Gordon Gribble on his retirement -indole chemist par excellence and delightful collaborator. A true gentleman and fine chemist.Received 11-08-2017 Accepted 02-12-2018 Published on line 03-14-2018
AbstractA synthesis of 5-(3,3-dimethyl-3H-indol-2-yl)-3-methyl-1H-pyrazolo [3,4-b]pyridines by the reaction of variously substituted aminomethylene malondialdehydes [2-(3,3-dimethyl-3H-indol-2-ylidene)malondialdehydes] with 5-amino-1-aryl-3-methylpyrazoles in the presence of p-toluenesulfonic acid in water is described.
The scarcity of fresh and hygienic water sources leads to a demand of more research for the treatment of wastewater. One of the possible ways is using a watermelon rind as a natural coagulant where its performance was investigated in terms of turbidity, pH and BOD. Watermelon rind (WR) and alum(A) at different compositions (WR100, WR50A50, WR70A30, A100) were introduced in the synthetic wastewater before treated on natural wastewater by jar test. Results revealed that the turbidity, pH as well as dissolved oxygen level were highly dependent on the coagulant dosage. About 90% of turbidity was reducing at 70% of powdered watermelon rind and 30% alum (WR70A30) on the contrary only 72% in natural wastewater. In addition, WR70A30 had better reduction in turbidity as compared to using 100A. On the other hand, final pH reading falls approximately in the range of 6 to 8, respectively which is acceptable for the standard wastewater discharge. Meanwhile, the results for the BOD5 for the natural wastewater is in the ranges between 0.35 to 1.39 had met the WHO standard. Finally, the FTIR analysis on treated and untreated watermelon rind confirms similar peaks of functional groups. Overall, the present study on WR as coagulant show a good performance in treating both natural and synthetic wastewater.
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