Michael addition reaction on 5,6-dimethoxy-2-methylene-2,3-dihydro-1H-inden-1-one: checking the products stability and evaluation of retro Michael reaction possibility

As for the importance of 1-indanone derivatives in this project, 5,6-dimethoxy-2- methylene-2,3-dihydro-1H-inden-1-one has been synthesized by evaluating the old methods and examination of new methods. alpha-beta unsaturated derivatives of 5,6-dimethoxy-1-indanone and diverse nucleophiles containing piperidine, N-methyl piperazine, morpholine, sodium azide, imidazole, benzimidazole, and pyrazole were reacted under Michael addition reaction condition and resulted in a variety of compounds with different stability. The possibility of retro-Michael reaction has been examined on the obtained products. The progress of this reaction depends on the stability of the synthesized 1-indanone derivatives. The results show compounds with aliphatic amines (piperidine, N-methyl piperazine, morpholine) have more appetency for participation in retro-Michael reaction vs compounds with aromatic amines (Imidazole, benzimidazole, pyrazole, except indole). The derivatives of aromatic amines usually show acceptable stability to the extent that they can be purified through column chromatography in contact with silica gel. Nevertheless, indole as an aromatic nucleophile is an exception; it has not completed the Michael addition reaction, and the final product in contact with silica gel under purification conditions using column chromatography performs the retro-Michael reaction. FT-IR, H-1, and C-13 NMR spectroscopy as well as elemental analysis supported the predicted structure of the product. [GRAPHICS] .

Automated summary

In this study, 5,6-dimethoxy-2-methylene-2,3-dihydro-1H-inden-1-one was synthesized by evaluating old methods and examining new methods. alpha-beta unsaturated derivatives of 5,6-dimethoxy-1-indanone were reacted with various nucleophiles under Michael addition reaction condition, resulting in compounds with different stability. The possibility of retro-Michael reaction was also examined. The synthesized 1-indanone derivatives played a crucial role in the progress of this reaction, with aliphatic amines showing more tendency for retro-Michael reaction compared to aromatic amines.