Synthesis of spiro[dihydropyridine-oxindoles] via three-component reaction of arylamine, isatin and cyclopentane-1,3-dione

• Yan Sun,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2013, 9, 8–14, doi:10.3762/bjoc.9.2

• -component reactions of arylamine, isatin and cyclopentane-1,3-dione in acetic acid at room temperature. On the other hand the condensation of isatin with two equivalents of cyclopentane-1,3-dione gave 3,3-bis(2-hydroxy-5-oxo-cyclopent-1-enyl)oxindole in high yields. The reaction mechanism and substrate

• scope of this novel reaction is briefly discussed. Keywords: arylamine; cyclopentanedione; isatin; multicomponent reaction; spiro compound; Introduction The spirooxindole is among the most important class of naturally occurring substances, characterized by highly pronounced biological properties, and

• [3][4][5][6]. Isatin and its derivatives may be the most useful starting materials or precursors in the synthesis of a wide number of spirocyclic oxindoles [7][8]. Due to its simple process, easy operation, efficiency and high atomic economy, the multicomponent reaction based on isatin and its

Mechanochemistry assisted asymmetric organocatalysis: A sustainable approach

• Pankaj Chauhan and
• Swapandeep Singh Chimni

Beilstein J. Org. Chem. 2012, 8, 2132–2141, doi:10.3762/bjoc.8.240

• with the aldehyde carbonyl in the transition state (TS 3). Under ball-milling conditions, thiodipeptide VI catalyses the enantioselective aldol reaction of acetone (1d) with isatin derivatives 4 to provide 3-substituted-3-hydroxyoxindole derivatives 5 in moderate yield (54–68%) and moderate to good

• of (A) ketones with aldehydes and (B) acetone with isatin derivatives. Enantioselective Michael reaction of aldehydes with nitroalkenes catalysed by pyrrolidine-derived organocatalysts. Chiral squaramide catalysed asymmetric Michael reaction assisted by ball-milling. Asymmetric organocatalytic

Organocatalytic asymmetric Michael addition of unprotected 3-substituted oxindoles to 1,4-naphthoquinone

• Jin-Sheng Yu,
• Feng Zhou,
• Yun-Lin Liu and
• Jian Zhou

Beilstein J. Org. Chem. 2012, 8, 1360–1365, doi:10.3762/bjoc.8.157

• enantioenriched 3-hydroxyoxindoles [22][23][24]. For the synthesis of chiral 3-aminooxindoles, we developed the first example of catalytic asymmetric addition of nucleophiles to isatin-derived ketoimines using TMSCN [25] and the amination of unprotected 3-prochiral oxindoles using di-tert-butyl azodicarboxylate

Expanding the chemical diversity of spirooxindoles via alkylative pyridine dearomatization

• Chunhui Dai,
• Bo Liang and
• Corey R. J. Stephenson

Beilstein J. Org. Chem. 2012, 8, 986–993, doi:10.3762/bjoc.8.111

• ], we previously reported a Lewis acid catalyzed, three-component synthesis of spirooxindole pyranochromenedione derivatives using isatin and two 1,3-dicarbonyl compounds (Scheme 1) [14]. Mechanistically, we believed this reaction to proceed through an intermediate isatylidene 1 [15][16][17]. As a means

• with isatin and 1,3-cyclohexanedione (5a) as coupling partners, we isolated a relatively poor yield of product 6a (Table 1, entry 1). We speculated that the free indole nitrogen was inhibiting the reaction, thus we switched to N-substituted isatins and found that the reaction improved to provide

• moderate to high yields (Table 1, entries 2–10). Subtle substitution effects were observed when the C(5)–H of isatin was replaced with various functionalities. Specifically, an electron-donating group at the 5-position, such as a methyl group, decreased the reactivity and only gave 57% yield (Table 1

An intramolecular inverse electron demand Diels–Alder approach to annulated α-carbolines

• Zhiyuan Ma,
• Feng Ni,
• Grace H. C. Woo,
• Sie-Mun Lo,
• Philip M. Roveto,
• Scott E. Schaus and
• John K. Snyder

Beilstein J. Org. Chem. 2012, 8, 829–840, doi:10.3762/bjoc.8.93

• Intramolecular inverse electron demand cycloadditions of isatin-derived 1,2,4-triazines with acetylenic dienophiles tethered by amidations or transesterifications proceed in excellent yields to produce lactam- or lactone-fused α-carbolines. Beginning with various isatins and alkynyl dienophiles, a pilot-scale

• library of eighty-eight α-carbolines was prepared by using this robust methodology for biological evaluation. Keywords: α-carboline; chemical diversity; inverse electron demand Diels–Alder; isatin; pyrido[2,3-b]indole; 1,2,4-triazine; Introduction In comparison with the well-known β-carbolines, α

• library of annulated α-carboline structures 6 could be prepared by the intramolecular inverse electron demand Diels–Alder reaction (IEDDA) of isatin-derived 1,2,4-triazines 7 with tethered electron-rich dienophiles (Scheme 1) [69]. Inverse electron demand Diels–Alder cycloadditions employing electron

Novel tetracyclic structures from the synthesis of thiolactone-isatin hybrids

• Renate Hazel Hans,
• Hong Su and
• Kelly Chibale

Beilstein J. Org. Chem. 2010, 6, No. 78, doi:10.3762/bjoc.6.78

• 7701, South Africa 10.3762/bjoc.6.78 Abstract A simple and straightforward synthetic approach to potential anti-infective thiolactone-isatin hybrids led to the discovery of novel tetracyclic compounds which bear a macrocylic motif containing an unusual bridged amide bond. Keywords: bridged amides

• ; hybrids; isatin; tetracycles; thiolactomycin; thiolactone; Introduction Hybrid structures have been found in nature and their synthesis has become a useful drug discovery strategy for new anti-infective agents [1]. Improved pharmacokinetics, therapeutic and toxicity profiles have been reported for

• natural and natural product-like hybrid constructs such as the artemisinin-quinine [2], nostocarboline-ciprofloxacin [3] and isatin-lamuvidine [4] (Figure 1). Interest in exploring this approach also derives from the pharmacophore-rich compound library it offers. This precludes the need for large

A thermally-induced, tandem [3,3]-sigmatropic rearrangement/[2 + 2] cycloaddition approach to carbocyclic spirooxindoles

• Kay M. Brummond and
• Joshua M. Osbourn

Beilstein J. Org. Chem. 2010, 6, No. 33, doi:10.3762/bjoc.6.33

• 5 could be obtained by way of a thermal [3,3]-sigmatropic rearrangement of the propargylic acetate 6 to give compound 5 where R2 = OAc (Figure 2) [27]. Preparation of propargylic acetate 9a was accomplished by the addition of the lithium acetylide of 8 to N-methyl isatin (7) followed by acetylation