Asymmetric synthesis of drug-like functionalized spiro[chroman-3,3'-indolin]-2'-ones 5 containing three contiguous stereocenters with high diastereo- and enantioselectivities was achieved using the reflexive-Michael (r-M) reaction of unmodified hydroxyenals 1 with various (E)-3-alkylideneindolin-2-ones 2 in the presence of (R)-DPPOTMS/AcOH (R)-3/4b as a catalyst at room temperature. Chiral spiro[chroman-3,3'-indolin]-2'-ones 5 were transformed into the functionalized spiranes 7, 9, and 10 in good yields with high selectivity through Wittig, TCRA, acetal protection and reduction reactions, respectively. Supporting evidence for the reaction pathway through the formation of the important catalytic species of "aminals" was observed through NMR and ESI-HRMS analysis of an ongoing reaction between 1 and (R)-3 in CDCl3 and also shown by the structural requirement in hydroxyenals 1 to generate the “aminals” with (R)-3 through controlled experiments.
A series of 1-(2-Oxo-2-phenyl-ethyl)-2-phenyl-1H-indole-3yl)methylene) semicarbazone derivatives (4a-g and 6a-c) were synthesized by the condensation of derivatives of 1-(2-Oxo-2-phenyl-ethyl)-2-phenyl-1H-indole-3-carbaldehyde and semicarbazide in ethanol under microwave irradiation procedure. Both conventional and microwave-irradiated syntheses have been carried out to compare their yields and reaction time. The structures of the synthesized compounds were confirmed by spectral data. The antimicrobial activities of the synthesized compounds were screened using broth dilution method. Among all the screened compounds some of the compounds exerted good antifungal activity against C. albicans and C. rugosa. All the compounds exhibited moderate activity against bacteria such as B. subtilis, S. aureus, S. epidermidis, E. coli, P. aeoginosa, and K. pneumoniae.
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