The syntheses of new 2,3-disubstituted 4-chloro-1-hydroxyindoles were described. The conjugate nitro ketoester was reacted with various thiol and alcohol nucleophiles by the action of stannous chloride dihydrate through the unique processes of reduction of nitro group, intramolecular condensation, and addition of nucleophiles in one pot, to provide multisubstituted 1-hydroxyindoles. The reactions with thiol nucleophiles provided better results than those with alcohols, and, in particular, secondary and tertiary thiols provided best yields.
Synthesis of New 2,3-Disubstituted 4-Chloro-1-hydroxyindoles. -Title compounds (VII) are prepared by reaction of conjugate nitro ketoester (V) with various thiol and alcohol nucleophiles by the action of stannous chloride dihydrate through the unique processes of reduction of nitro group, intramolecular condensation, and addition of nucleophiles in one pot, to provide multisubstituted 1-hydroxyindoles. The reactions with thiol nucleophiles provide better results than those with alcohols [cf. (IXd)]. Interestingly, the reaction of (V) with phenol leads to the C-alkylated adduct (XI) without the expected O-alkylated adduct, which is consistent with the previous observations. -(PARK, Y. K.; KIM, H.; KIM, D. S.; CHO, H.; MOON, A.; JEONG, C.; YOON, H.-R.; LEE*, S. H.; Bull. Korean Chem. Soc. 36 (2015) 8, 2095-2100, http://dx.doi.org/10.1002/bkcs.10410 ; Coll. Pharm., Duksung Women's Univ., Seoul 132-714, S. Korea; Eng.) -M. Bohle 01-116
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