Indane-1,3-diones synthesis

Shu-Jiang and co-workers [76] have developed a green approach for the synthesis of biologically important indeno[2,l-c]pyrazolo[5,4-/7]pyridines 36 via a MCR of a suitable aldehyde, 3-methyl-l-phenyl-l//-pyrazol-5-amine and 1,3-indane-dione in water under microwave irradiation without the aid of any catalyst. This protocol has the prominent advantages of being environmentally benign and having... 

A further interesting case is provided by the synthesis of ninhydrin (Expt 5.99, cognate preparation) from indane-l,3-dione (Expt 7.9) in which the methylene group is activated by two adjacent carbonyl groups. Ninhydrin is the stable monohydrate of the triketone, indane-l,2,3-trione, and is a well-known colorimetric reagent for amino acids (Section 2.31). 

The forward synthetic reaction (formulated in Expt 7.9) is thus an initial mixed Claisen ester condensation, followed by a Dieckmann cyclisation, hydrolysis and decarboxylation. Indane-l,3-dione is used for the synthesis of the trione, ninhydrin (Expt 5.99). 

Fig. 3. Gabriel and Michael s 1877 conversion of phthalylacetic acid (3) to tribenzoylenebenzene and Wislicenus s 1887 synthesis of truxone from indane-l,3-dione (5) both products turned out to have the same structure (4).

Sartori, G., Bigi, R, Maggi, R., Baraldi, D., and Casnati, G. 1992. Acylation of aroyl chlorides via a template Friedel-Crafts process synthesis of indan-l,3-diones. /. Chem. Soc., Perkin Trans. 1 2985-2988. 

Additional modifications to the Hantzsch 1,4-dihydropyridine synthesis generally involve the use of activated methylene compounds such as 1,3-diketones, co-cyanoacetophenone, co-phenylacetophenone, a, P-unsaturated ketones, and indane-l,3-diones. A number of efforts to improve reaction yields using eatalysts have also been reported, including the use of hydrotalcite materials, triphenylphosphine copper II triflate, and covalently anchored sulfonic acid on silica gel. Dihydropyridine synthesis has also recently been studied with high success using microwave and solvent-free" reaction conditions. 

A. R. Kazemizadeh, A. Ramazani, J. Braz. Chem. Soc. 2009,20, 309-312. Passerini multicomponent reaction of indane-1,2, 3-trione an efficient route for the one pot synthesis of stericaUy congested 2,2-disuhstituted indane-l,3-dione derivatives. 

L. S. Liebeskind, S. L. Baysdon, M. S. South, and J. F. Blount, J. Organomet. CAem.,1980, 202, C73. High yield synthesis of metalla-2-indane-l,3-diones. 

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