Synthesis of glucosylspiro-oxindole derivatives via one-pot three-component cycloaddition of azomethine ylides

Highly regio- and stereoselective synthesis of glucosylspiro-oxindole/acenaphthenone derivatives was accomplished through 1,3-dipolar cycloaddition (1,3-DC) reaction. The glucosyl α,β-unsaturated-7,3-lactone (a sugar lactone) derived from d-glucose was used as a chiral dipolarophile in 1,3-DC reaction for the first time. The azomethine ylides generated from sarcosine/l-proline/thiazolidine-4-carboxylic acid/piperidine-2-carboxylic acid with isatin and acenaphthoquinone were trapped by the sugar lactone to give a series of glucosylspiro-pyrrolidine derivatives in good yields.     

Synthesis of bis-spirofused thiapyrrolizidinooxindoles by 1,3-dipolar cycloaddition

The 1,3-dipolar cycloaddition of unstabilized azomethine ylide, which is generated in situ from isatin and thiaproline, to arylidene derivatives of rhodanine affords bis-spirofused thiapyrrolizidinooxindoles. The 1,3-dipolar addition reactions under consideration are fully regio- and diastereoselective.     

An expedient approach for the synthesis of dispiropyrrolidine bisoxindoles, spiropyrrolidine oxindoles and spiroindane-1,3-diones through 1,3-dipolar cycloaddition reactions

A series of dispiropyrrolidine bisoxindoles were synthesized via a multicomponent 1,3-dipolar cycloaddition reaction of isatin, sarcosine and isatylidene malononitrile in refluxing methanol. Also a series of spiropyrrolidine oxindoles and spiroindane-1,3-diones were synthesized using 2-(1H-Indole-3-carbonyl)-3-phenyl-acrylonitrile and 2-(1,3-dioxo-indan-2-ylidene)-malononitrile as dipolarophiles, respectively.     

An easy access to novel steroidal dispiropyrrolidines through 1,3-dipolar cycloaddition of azomethine ylides

A facile one-pot synthesis of novel steroidal dispiropyrrolidines has been accomplished by 1,3-dipolar cycloaddition reaction of various azomethine ylides derived from isatin/acenaphthenequinone/ninhydrin and sarcosine with various estrone derivatives as dipolarophiles, in good yield. The effect of various solvents on the 1,3-dipolar cycloaddition reaction are also studied.     

An expedient synthesis of pyrrolidinyl spirooxindole grafted 3-nitrochromanes through 1,3-dipolar cycloaddition reaction of azomethine ylides

A facile one-pot synthesis of pyrrolidinyl-spirooxindole grafted 3-nitrochromanes has been accomplished by 1,3-dipolar cycloaddition (1,3-DC) reaction of 3-nitrochromenes with azomethine ylides generated in situ from isatin and secondary amino acids. The regio- and stereochemical outcome of the cycloaddition reaction was ascertained by X-ray crystallographic analysis.     

Three-component synthesis of spiro compounds with a carbamate functionality

1,3-Dipolar cycloaddition of methyl 4-[2-(2-oxo-1,2-dihydro-3H-indol-3-ylidene)acetyl]phenylcarbamate to non-stabilized azomethine ylides generated by decarboxylation of α-amino acid (sarcosine and proline) adducts with ketones (isatin and ninhydrin) occurred regioselectively with formation of the corresponding spiro compounds having a carbamate moiety.     

Diastereoselective cycloaddition of isatin azomethine ylides to 5-arylidene-2-thiohydantoins bearing 3-positioned chiral substituent

1,3-Dipolar cycloaddition of azomethine ylide, generated from isatin and sarcosine, with 5-arylidene-2-thiohydantoins equipped with various chiral substituents at the N³ atom occurs diastereoselectively. The highest selectivity with dr = 5 : 1 was observed for the 2-thiohydantoin bearing 1,2-diphenylethyl substituent.     

TiO2-silica mediated one pot three component 1,3-dipolar cycloaddition reaction: a facile and rapid synthesis of dispiro acenaphthenone/oxindole [indanedione/oxindole] pyrroloisoquinoline ring systems

TiO₂-silica is used as an efficient solid-supported catalyst for the synthesis of a series of novel dispiroheterocyclic systems by the cycloaddition of an azomethine ylide generated by the decarboxylative route from tetrahydroisoquinoline-3-carboxylic acid and acenaphthenequinone/isatin with various unusual dipolarophiles such as 2-arylidene-1,3-indanediones and (E)-2-oxoindolino-3-ylidene acetophenones in a one pot three component tandem reaction, in moderate to good yields. The regiochemistry and stereochemistry of the title compound were established by spectroscopic techniques.     

Multicomponent domino protocol for the stereoselective synthesis of novel pyrrolo[3,2-c]quinolinone hybrid heterocycles

A series of structurally intriguing novel pyrrolo[3,2-c]quinolinone heterocyclic hybrids have been synthesized for the first time via a one-pot multicomponent domino reaction sequence that involves a 1,3-dipolar cycloaddition and two subsequent annulation steps. Baylis-Hillman adducts derived from various substituted benzaldehyde and methyl acrylate in presence of DABCO were used as a dipolarophiles, while the 1,3-dipole components were azomethine ylides, formed in situ from isatin derivatives and l-phenylalanine. The reaction generated five new bonds, three new rings and four contiguous stereocenters, which were created with full diastereomeric control.     

Direct construction of novel exo′-selective spiropyrrolidine bisoxindoles via a three-component 1,3-dipolar cycloaddition reaction

An efficient synthesis of novel exo′-selective spiropyrrolidine bisoxindoles has been achieved via a three-component 1,3-dipolar cycloaddition reaction. The azomethine ylides generated in situ from substituted isatin and primary α-amino acid methyl ester (or primary α-amino acids) reacted with the Knoevenagel adducts of substituted isatin to furnish novel spiropyrrolidine bisoxindoles in high yields (up to 99%). The structure and relative stereochemistry of cycloadducts were confirmed by single crystal X-ray diffraction. The possible mechanism was proposed and the cycloaddition proceeded via exo′-transition state.     

Synthesis of dispiro[1-benzothiophene-2,3'-pyrrolidine-2',3”-indoline]-2”,3-diones in cycloaddition reaction

Chemistry of Heterocyclic Compounds - The 1,3-dipolar cycloaddition of azomethine ylides derived from isatin and sarcosine to (Z)-2-(arylmethylidene)-1-benzothiophen-3(2H)- ones afforded novel...     

Synthesis of Novel Trispiroheterocycles through 1,3-Dipolar Cycloaddition of Azomethine Ylides and Nitrile Oxide

The 1,3‐dipolar cycloaddition of an azomethine ylide generated by a decarboxylative route from sarcosine and isatin to 1‐benzyl‐3,5‐diarylmethylidene‐piperidin‐4‐ones afforded novel di‐spiro‐indolo/pyrrolidino/piperidines in moderate yields. Further cycloaddition of these di‐spiro compounds to nitrile oxide afforded tri‐spiro‐indolo/pyrrolidino/piperadino/isoxazolines in moderate yields with high regio‐ and stereoselectivity.     

One Pot Synthesis of Some New Spiro[3H-Indol-3,5′(4′H)-[1,2,4] Oxadiazol]-2-Ones and Bis[Spiro[3H-Indol-3,5′(4′H)-[1,2,4] Oxadiazol]-2-Ones]

A facile preparation of the title compound by 1,3-dipolar cycloaddition reaction of benzonitrile oxides with isatin imines or isatin diimines, in excellent yield, are reported.     

Direct construction of novel dispiro heterocycles through 1,3-dipolar cycloaddition of azomethine ylides

The 1,3-dipolar cycloaddition of 2-oxo-(2H)-acenaphthylen-1-ylidene-malononitrile and 2-fluoren-9-ylidene-malononitrile as dipolarophiles have been investigated for the first time with the azomethine ylides generated in situ from N-substituted isatin and sarcosine to furnish novel dispiro heterocycles. The structure and relative stereochemistry of both types of cycloadducts were confirmed by single crystal X-ray diffraction, as well as with the help of ¹H, ¹³C, and HMBC spectroscopic methods.     

Synthesis of novel spiro-[3H-indole-3,3′-[1,2,4]triazolidine]-2-ones via azomethine imines

Novel spiroindoles 5 are prepared easily via a one-pot, 1,3-dipolar cycloaddition reaction of azomethine imines with isatin imines under thermal conditions.     

A regioselective synthesis of dispiro[oxindole-cyclohexanone]pyrrolidines and dispiro[oxindole-hexahydroindazole]pyrrolidines by sequential 1,3-dipolar cycloaddition and annulation through a microwave induced solvent-free approach

The 1,3-dipolar cycloaddition of an azomethine ylide, generated from isatin and benzylamine by a 1,5-prototopic shift route with various p-substituted 2,6-bis(arylmethylidene)cyclohexanones under different conditions, proceeded regioselectively to give novel dispiroheterocycles. The product on subsequent annulation with hydrazine hydrate afforded 4-aryl-5-phenyl(spiro[2.3″]oxindole)3′-aryl-3′,3a′,4′,5′,6′,7′-hexahydro-2H-indazolospiro[7′.3]pyrrolidines in good yield.     

Regioselective synthesis of spiropyrrolidine/spiropyrrolizidine/spirothiazolidine-grafted macrocycles through 1,3-dipolar cycloaddition methodology

Synthesis of 13- and 16-membered macrocyclic enone with alkyl ether and triazole as a linker was achieved using intramolecular aldol condensation. The newly synthesized macrocyclic enone was successfully utilized as a dipolarophile in 1,3-dipolar cycloaddition (1,3-DC). The dipole generated from isatin/acenaphthenequinone with various secondary amino acids (sarcosine, l-proline, and thiazolidine-4-carboxylic acid) were reacted with macrocyclic enone to give a new class of spiropyrrolidine-grafted macrocycles in good yield (>85%). The structures were assigned by 2D NMR spectra and the regio- and stereochemical outcome of the cycloadducts were established by a single crystal X-ray analysis.     

A facile synthetic approach to novel spiro-oxindoles/acenaphthylen-1-ones containing benzo[1,4]thiazin-3-one ring via 1,3-dipolar cycloaddition

A series of spiro-oxindole derivatives containing spirobenzo[1,4]thiazin-3-one ring were synthesized regioselectively via a multicomponent 1,3-dipolar cycloaddition of isatin, 2-(4-methyl-benzylidene)-4H-benzo[1,4]thiazin-3-one and sarcosine or l-proline in toluene under reflux condition. Also spiro-acenaphthylen-1-ones containing spirobenzo[1,4]thiazin-3-one ring have been synthesized using 2-(4-methyl-benzylidene)-4H-benzo[1,4]thiazin-3-one as dipolarophile. The methodology affords high yields of products in short reaction time.     

Asymmetric Dearomative (3+2)-Cycloaddition Involving Nitro-Substituted Benzoheteroarenes under H-Bonding Catalysis

In our studies, the organocatalytic 1,3-dipolar cycloaddition between 2-nitrobenzofurans or 2-nitrobenzothiophene and N-2,2,2-trifluoroethyl-substituted isatin imines has been developed. The reaction has been realized by employing bifunctional organocatalysis, with the use of squaramide derivative being crucial for the stereochemical efficiency of the process. The usefulness of the cycloadducts obtained has been confirmed in selected transformations, including aromative and non-aromative removal of the nitro group.     

A facile synthesis of novel endo-selective polycyclic spiropyrrolidine oxindoles via 1,3-dipolar cycloaddition of α,γ-dialkylallenoate esters

Novel polycyclic spiropyrrolidine oxindoles that bear two vicinal quaternary centers and an exocyclic CC double bond have been synthesized by a three-component reaction involving α,γ-dialkylallenoate esters, isatin derivatives and amino acids, by way of an endo-selective 1,3-dipolar cycloaddition. These reactions proceed in high yields and diastereoselectivities. The structures and relative stereochemistry of products were confirmed by NMR, HRMS and X-ray crystallography.