Synthesis of dispirooxindolecycloalka[d]pyrimidino[2,3-b]-thiazole pyrrolidine/thiapyrrolizidine ring systems

An efficient one-pot synthesis and docking studies of bioactive new antiproliferative dispiro[oxindole/acenaphthylenone‒benzofuranone] pyrrolidine scaffolds

A new and efficient method has been developed to synthesize dispiro[oxindole/acenaphthylenone-benzofuranone]pyrrolidine compounds. This is done by triggering the 1,3-dipolar cycloaddition reaction of azomethine ylides by reacting isatin/acenaphthoquinone with L-picolinic acid/L-proline/sarcosine/L-thioproline/tetrahydroisoquinolines, in a highly regioselective manner in an ionic liquid [DBU][Ac] with 4'-chloro-auron[2-(4-chlorobenzylidene)benzofuran-3(2H)-one]. Single-crystal X-ray diffraction data support the proposed structures of the new compounds. The heterocycles derived from amino acids such as L-picolinic acid, L-proline, and L-thioproline showed significant inhibitory effects against six human solid tumors, including lung, breast, cervix, colon, and others. These new structures were also tested in the active sites of the MDM2 receptor to further study their antiproliferative effects.

Azomethine Ylides-Versatile Synthons for Pyrrolidinyl-Heterocyclic Compounds

Azomethine ylides are nitrogen-based three-atom components commonly used in [3+2]-cycloaddition reactions with various unsaturated 2π-electron components. These reactions are highly regio- and stereoselective and have attracted the attention of organic chemists with respect to the construction of diverse heterocycles potentially bearing four new contiguous stereogenic centers. This review article complies the most important [3+2]-cycloaddition reactions of azomethine ylides with various olefinic, unsaturated 2π-electron components (acyclic, alicyclic, heterocyclic, and exocyclic ones) reported over the past two decades.

An effective one-pot access to polynuclear dispiroheterocyclic structures comprising pyrrolidinyloxindole and imidazothiazolotriazine moieties via a 1,3-dipolar cycloaddition strategy

An effective and highly regio- and diastereoselective one-pot method for the synthesis of new polynuclear dispiroheterocyclic systems with five stereogenic centers (dispiro[imidazo[4,5-e]thiazolo[3,2-b]-1,2,4-triazine-6,3'-pyrrolidine-2',3''-indoles]) comprising pyrrolidinyloxindole and imidazo[4,5-e]thiazolo[3,2-b]-1,2,4-triazine moieties has been developed. The method relies on a 1,3-dipolar cycloaddition of azomethine ylides generated in situ from isatin derivatives and sarcosine to 6-benzylideneimidazo[4,5-e]thiazolo[3,2-b]-1,2,4-triazine-2,7-diones.

Molecular diversity of spirooxindoles. Synthesis and biological activity

Spirooxindoles are important synthetic targets possessing extended biological activity and drug discovery applications. This review focuses on the various strategies for the enantioselective synthesis of spirocyclic oxindoles relying on reports over the past decade and from earlier work. The spirooxindoles in this review are separated into three structural classes, and then further categorized into the method type from which the spirocycle is generated.

A facile synthesis and antimycobacterial evaluation of novel spiro-pyrido-pyrrolizines and pyrrolidines

An efficient synthesis of 1-methyl-3-[(E)-arylmethylidene]tetrahydro-4(1H)-pyridinones was achieved by the reaction of 1-methyl-4-piperidone and aromatic aldehydes in the presence of pyrrolidine under solvent-free microwave irradiation. These dipolarophiles upon cycloaddition with nitrile oxide and azomethine ylides afford stereoselectively novel spiro-isoxazolines, pyrrolizines and pyrrolidines respectively in excellent yields. The spiro compounds were screened for their in vitro activity against Mycobacterium tuberculosis H37Rv (MTB), multi-drug resistant M. tuberculosis (MDR-TB) and Mycobacterium smegmatis (MC(2)) using agar dilution method. Among the synthesized compounds, 1-methyl-4-(2,4-dichlorophenyl)pyrrolo(spiro[2.3'']oxindole)spiro[3.3']-1'-methylpiperidin-4'-one was found to be the most active with a minimum inhibitory concentration (MIC) of 1.76 and 0.88 microM against MTB and MDR-TB respectively.

Regioselective Synthesis of rac-(1R,4R,6R,6aR)-6′-phenyl-7′,8′-dihydro-1″H,2′H,6′H-dispiro[cycloalkane-1,5′-pyrrolo[1,2-c][1,3]thiazole-4′,3″-indole]-2,2″-diones through 3 + 2 cycloaddition Reaction

Synthesis of a series of novel rac-(1 R,4 R,6 R,6a R)-6′-phenyl-7′,8′-dihydro-1″ H,2′ H,6′ H-dispiro[cycloalkane-1,5′-pyrrolo[1,2- c][1,3]thiazole-4′,3″-indole]-2,2″-diones by cycloaddition reaction is described. The nonstabilised azomethine ylide generated by the reaction of isatin and thiazolidine-2-carboxylic acid has been regioselectively trapped by various substituted benzylidene cycloalkanones.

Ethyl 1'-[1-(4-methoxyphenyl)-3-phenoxy-4-phenylazetidin-1-yl]-1,3-dioxo-2′,3′,5′,6′,7′,7a′-hexahydroindan-2-spiro-3′-1′H-pyrrolizine-2′-carboxylate

In the title compound, C₃₄H₃₂N₂O₇, the methyl group and methylene H atoms of the ethoxycarbonyl substituent are disordered over two positions with site occupancy factors for the major and minor conformers of 0.594 (8) and 0.406 (8), respectively. The unsubstituted ring of the pyrrolizine ring system exhibits a twist conformation, the other an envelope conformation. In the crystal structure, mol­ecules are linked through C—H⋯O hydrogen bonds; intramolecular C—H⋯O interactions are also observed.

1'-Methyl-4'-(1-naphth-yl)-3''-(1-naphthyl-methyl-ene)acenaphthene-1-spiro-2'-pyrrolidine-3'-spiro-1''-cyclo-hexane-2,2''-dione

In the title compound, C(42)H(33)NO(2), the six-membered cyclo-hexa-none ring adopts a slightly distorted chair conformation and the five-membered pyrrolidine ring is in an envelope conformation. The mol-ecular structure features four intra-molecular C-H⋯O inter-actions and an intra-molecular C-H⋯π inter-action. Furthermore, the crystal packing is stabilized by an inter-molecular C-H⋯O and three inter-molecular C-H⋯π inter-actions.