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Aldol addition of acyclic and cyclic ketones to 4,4,6-trimethyl-4H-pyrrolo[3,2,1-ij]quinoline-1,2-diones afforded the corresponding 1-substituted 1-hydroxy-4,4,6-trimethyl-4H-pyrrolo[3,2,1-ij]quinolin-2(1H)-ones. The short-time reduction of 4,4,6-trimethyl-4H-pyrrolo[3,2,1-ij]quinoline-1,2-diones with sodium tetra-hydridoborate gave 1-hydroxy-4,4,6-trimethyl-4H-pyrrolo[3,2,1-ij]quinolin-2(1H)-ones. [ABSTRACT FROM AUTHOR]

This study investigates the effects of new solid solvent, polybutylisocyanate (PBI) on the aldol reaction using alkali metal salt as a catalyst. The polyisocyanate chain incorporated into the Wang resin under anionic conditions was analyzed after the cleavage by trifluoracetic acid. In the absence of PBI, the aldol reaction proceeded unsatisfactory to afford the corresponding product (2a) in only 13 percent yield. Therefore it was speculated that PBI had the sufficient space to progress the reaction effectively owing to rigid polymer backbone. Since the free polymeric amide units should trap the metal catalyst more effectively and provide the space for the substrates more readily than those in the rigid structure. As the result, it was indicated that PBI was more appropriate solid solvent for the reaction. The combination of magnesium chloride with PBI was also effective to obtain 2a in the good yield such as 73 percent. However, no enhancement of the reaction was observed in the use of zinc bromide. On the other hand, in the case of alkali metal salts and alkaline earth metal salts, anion species seemed to activate dimethylsilyl enolate. Therefore, the amide units in PBI, which should coordinate the cation species and contribute to the formation of anion species, might be effective in those cases.