C-3 alkylation of oxindole with alcohols by Pt/CeO<sub>2</sub> catalyst in additive-free conditions
作者:Chandan Chaudhari、S. M. A. Hakim Siddiki、Kenichi Kon、Atsuko Tomita、Yutaka Tai、Ken-ichi Shimizu
DOI:10.1039/c3cy00911d
日期:——
In a series of transition metal-loaded CeO2 catalysts and Pt-loaded catalysts on various supports, Pt-loaded CeO2 shows the highest activity for the selectiveC-3alkylation of oxindole with octanol. The catalyst is effective for alkylation of oxindole and N-substituted oxindole with a series of substituted benzyl, linear, hetero-aryl alcohols under additive-free conditions and is recyclable. Our results
The asymmetric catalytic synthesis of 3-cyclotryptamine substituted oxindoles through formal [4 + 2] cycloaddition/cyclization cascade is described. A wide range of cyclotryptamine derivatives were obtained in enantioenriched form under mild reaction conditions and were found to have potential anticancer activity. The strategy enables ready assembly of cyclotryptamine subunits at the C3a–C3a′ positions
描述了通过正式的[4 + 2]环加成/环化级联反应3-环色胺取代的羟吲哚的不对称催化合成。在温和的反应条件下,以对映体富集的形式获得了广泛的环色胺衍生物,发现它们具有潜在的抗癌活性。该策略使C 3a – C 3a'位置的环色胺亚基易于组装,并具有两个四级立体异构中心,具有顺式选择性,从而可以合成光学活性的顺式双(六氢吡咯并吲哚)和环色胺生物碱家族的其他化合物。
Highly Enantioselective Synthesis of 3-Amino-2-oxindole Derivatives: Catalytic Asymmetric α-Amination of 3-Substituted 2-Oxindoles with a Chiral Scandium Complex
A highly enantioselective α‐amination of 3‐substitutedoxindoles with azodicarboxylates catalyzed by a chiral Sc(OTf)3/N,N′‐dioxide complex (Tf: triflate) has been developed and affords the corresponding 3‐amino‐2‐oxindole derivatives in high yields (up to 98 %) with excellent enantioselectivities (up to 99 % ee). The procedure is capable of tolerating a relatively wide range of substrates, and excellent
Based on the hits, 3,4-dihydroquinazoline-2-thione (1) and benzimidazole-2-thione (2), a series of indole-2-thione (3) and indole-2-thiol inhibitors (4) of melanogenesis were designed, synthesized and evaluated in melanoma B16 cells under the stimulant of α-melanocyte stimulating hormone (α-MSH). The indole-2-thione compounds (3a—g) exhibited an effective inhibitory activity on melanin synthesis. The Structure–Activity Relationship (SAR) studies of 2 have revealed that in potent inhibitor 3a (>100% inhibition at 30 μM, IC50=1.40 μM) the role of nitrogen (3-N) at 3-position is insignificance. In addition, the hydrophobic substituents of 3 were better than the hydrophilic one. However, conversion of thione (–C=S, 3) to thiol (–C–SH, 4) led to decrease in the potency.