Data on methods for the synthesis of 2,3-dihydro-2,3-pyrrolediones condensed with azaheterocycles on the [a] side are reviewed. Their reactions with nucleophilic reagents, allylboronation, reduction, and thermal transformations are discussed.The chemistry of 2,3-dihydro-2,3-pyrrolediones condensed with azaheterocycles on the [a] side first evolved in the seventies, when the application of 2,3-dihydro-2,3-pyrroledione derivatives as synthetic blocks for the construction of alkaloid molecules was first demonstrated [1][2][3][4][5][6][7].It should be mentioned that up to the beginning of the nineties these annelated dihydropyrrolediones were studied almost exclusively as subjects for photoreduction and photocyclization or as dienophiles in DielsAlder reactions (for the production of intermediate compounds in the synthesis of alkaloids). A large part of these papers belong to certain groups of investigators [1][2][3][4][5]. Single reports on reactions with nucleophilic reagents, allylboronation, reduction, and thermal transformations of 2,3-dihydro-2,3-pyrrolediones annelated with azaheterocycles on the [a] side have only begun to appear comparatively recently. This region of their chemical behavior has been studied little in spite of the fact that they exhibit high reactivity toward various nucleophiles (particularly with the presence of several electron-withdrawing substituents in the rings) and generate imidoylketenes during thermolysis.In the present review we examine publications existing up to March, 2002, on methods for the production of dihydropyrrolediones condensed with azaheterocycles and their chemical transformations. The review does not include data on the chemistry of isatins and their aza analogs, which were described in [8], or data on the cycloaddition of these pyrrolediones, which have been discussed before [1][2][3][4][5][6][7][9][10][11] and were reviewed in [11].
A microwave-assisted, environmentally benign green protocol for the synthesis of functionalized (Z)-3-(2-oxo-2-phenylethylidene)-3, 4-dihydro-2H-benzo [b][1,4]oxazin-2-ones (11a-n) in excellent yields (upto 97%) and (Z)-3-(2-oxo-2-phenylethylidene)-3,4-dihydroquinoxalin-2(1H)-ones (14a-h) (upto 96% yield) are reported. The practical applicability of developed methodology were also confirmed by the gram scale synthesis of 11a, 14c and 14e; synthesis of anticancer alkaloid Cephalandole A 16 (89% yield). All the synthesized compounds 11a-n, 14a-h and 16 were assessed for their in vitro antioxidant activities in DPPH radical scavenging and FRAP assay. In DPPH assay, compounds 11a, 14c and 14e, the most active compounds of the series, were found to show IC 50 value of 10.20 ± 0.08 μg/mL, 9.89 ± 0.15 μg/mL and 8.97 ± 0.13 μg/mL, respectively in comparison with standard reference (ascorbic acid, IC 50 = 4.57 μg/mL). Whereas, in FRAP antioxidant assay seven compounds (11c, 11e, 11i, 11k, 11l, 14d and 14h) displayed higher antioxidant activity in comparison to the reference standard BHT (C 0.5 FRAP = 546.2 μM). Moreover, the cytotoxic studies of the compounds 11a, 14c, 14e and 14h were found to be non-toxic in nature in 3T 3 fibroblast cell lines using MTT assay.
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