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A practical approach for rapid and efficient access to spirocyclic isobenzofurans is described. The reaction proceeds through the cycloaddition of 1,6-ynenone derivatives and 4-nitro-1,3-diarylbutan-1-ones, promoted by Cs2CO3in the presence of l-proline as a catalyst. The advantages of this reaction include the formation of two C–C bonds and one C–O bond as well as mild reaction conditions. Extended spirocyclic isobenzofurans are obtained with good efficiency and diastereoselectivity under these mild conditions, and this new protocol avoids the use of any transition-metal reagents.

The synthesis of pyrrolidin-5-one-2-carboxamides 6a-phas been developed viaa one-pot Ugi reaction of allenic acids, primary amines, isocyanides, and aldehydes followed by regioselective cyclization of the resultant N-substituted-2-allenamides with KOt-Bu at room temperature. The cyclization reaction was carried out through a 5-exo-dig approach, which resulted in good yields and high atom-economy under transition-metal-free and mild reaction conditions.

Practical Pd-catalyzed 2-pyridones were designed to achieve chromeno[2,3-b]pyridine-2-ones. The reaction proceeds through domino nucleophilic addition and decarboxylative arylation, respectively. This methodology offers a moderately efficient approach to construct the bioactive, fused-heterocyclic skeletons via selective C–O bond formation and decarboxylative arylation in a single step with high selectivity and good yields.

In this project, a moderately efficient approach to multisubstituted N-(isoquinolin-1-yl)sulfonamide derivatives was illustrated, utilizing ortho-alkynylbenzaldoximes and zwitterionic ketenimine salts in a tandem reaction catalyzed by silver oxide. The oxophilicity of Ag2O, along with its nature as Lewis acid, pave the way for a smooth [3 + 2] cycloaddition between isoquinoline N-oxides and ketenimine species, which is a key step in this reaction. DFT calculation suggests that 1,3-dipolar cycloaddition of nitrone and ketenimine proceeds through a selective stepwise mechanism.

A novel series of functionalized heterocyclic compounds containing the chromone skeleton was achieved by a mild K2CO3(20 %)-catalyzed one-pot three-component reaction of 3-formylchromone, malononitrile, and active methylene compounds or pyrones in aqueous media. Good to high yields, easy workup, and also environmentally friendly character are advantages for this approach.

Trifluoroethanol as an efficient media for the domino Knoevenagel–hetero-Diels–Alder reaction of O-propargyloxy benzaldehydes as non-activated terminal alkynes with some active methylene compounds has been described. Short reaction time, easy work-up, good to high yields, and mild reaction conditions are advantages of this new media.

An efficient one-pot synthesis of novel 2,5-dihydro-1,2-oxaphosphole derivatives via a three-component reaction of triphenyl phosphine, dialkyl acetylenedicarboxylates, and methyl (arylmethylidene) pyruvates has been reported. Carrying out the reaction in mild reaction conditions and synthesis of functionalized oxaphospholes are advantages of this approach.

An efficient regio and stereoselective synthesis of functionalized E-vinyl ethers are described. The reaction could proceed via addition of primary alcohols and phenols to functionalized N-substituted 2-alkynamides which are produced via Ugi-4CR in the presence of triethylamine at room temperature. The reaction proceeds through sequential Ugi/nucleophilic reaction sequence. High yields, short reaction times, and simple operations are the advantages of this approach.

The one-pot three-component reaction of primary and secondary amines, carbon disulfide and β-nitrostyrene derivatives in neat condition at room temperature afforded functionalized dithiocarbamate derivatives in good to high yields. High bond-forming efficiency and easy work-up are advantages of this reaction. In vitro antimicrobial activities of synthesized compounds were studied against four Gram-positive bacteria, four Gram-negative bacteria and four fungi. The screening for the antimicrobial activity was performed by twofold serial dilution technique. Notably, some synthesized compounds displayed comparable or even better antibacterial and antifungal activities against some tested strains than the reference drugs ampicillin, streptomycin and amphotericin B, respectively.A series of novel dithiocarbamates 4a-jhave been synthesized via three-component reaction and compared pharmacologically concerning their antimicrobial and antibacterial activities as well as antifungal activity .

An efficient 1-methylimidazole-catalyzed synthesis of dialkyl 2-[(4-methylphenyl)sulfonyl]-1H-pyrrole-3,4-dicarboxylates is described. The reactive 1:1 zwitterionic intermediate formed by the addition of 1-methylimidazole to dialkyl acetylenedicarboxylates is trapped by tosylmethyl isocyanide (TOSMIC) to afford the title compounds in excellent yields.

3-mercapto-2-butanone undergoes a smooth reaction with electron-deficient symmetric and asymmetric acetylenes in the presence of catalytic amount of triphenylphosphine under neutral conditions to produce S-functionalized vinyl sulfides (Z/E isomers) in moderately high yields.

The reaction of 2-methyl-3-hydroxy-4H-pyrane-4-one (maltol) with dialkyl acetylenedicarboxylates in the presence of triphenylphosphine in CH2Cl2 at room temperature leads to the unknown fused furan and cyclobutene derivatives, and functionalized olefins in fairly high yields.

Here, online 1H‐NMR spectroscopy has been successfully applied to investigate the kinetic parameters of radical copolymerization of styrene (St) and itaconic acid (IA). This technique was used because it allowed us to individually map out the monomer conversions of St and IA during the course of the polymerization at various conversions. This was possible because the individual contributions to the overall monomer conversion from St and IA could be measured through their nonoverlapping vinylic proton signals. The results of monomer conversion during the time in the corresponding 1H‐NMR spectra was the basis of our analysis to determine the reactivity ratios of St and IA in the solution and radical copolymerization reaction by several methods. In addition to linear least‐squares methods, such as Finemann–Ross, inverted Finemann–Ross, Mayo–Lewis, Kelen–Tudos, extended Kelen–Tudos, and Mao–Huglin, a nonlinear least‐square method (Tidwell–Mortimer) was used for this purpose, at low conversions. Extended Kelen–Tudos and Mao–Huglin were applied to determine the reactivity ratio values at high conversions too. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2062–2069, 2006

Using phosphorus pentachloride as a substrate, carbacylamidophosphates of the general formula (p‐X‐C6H4) C(O)NHP(O)(R)2; (X=Cl and R=Cl, 2a; X=Br and R=Cl, 3a; X=Me and R=Cl, 4a; X=Cl and R=piperidine, 2b; X=Br and R=piperidine, 3b; X=Me and R=piperidine, 4b; X=H and R=cyclohexylamine, 1c; X=Cl and R=cyclohexylamine, 2c; X=Br and R=cyclohexylamine, 3c; X=Me and R=cyclohexylamine, 4c; X=H and R=p‐Me‐cyclohexylamine, was prepared and characterized by 1H, 31P and 13C NMR and IR spectroscopy and elemental analysis. Different group attached on phosphorus nuclei affect on IR and NMR spectra. Three‐bond coupling constants between phosphorus and carbon nucleus, 3J(P,Caliphatic) in the 1b–4band 1c–4ccontaining piperidine or cyclohexylamine groups, were greather than two‐bond coupling constants, 2J(P,Caliphatic). The structures of 2band 3bwere determined by single‐crystal X‐ray diffraction techniques. The both molecule crystals are composed of a centrosymmetric dimer via N‐H···O bonds. 3bexists as two independent molecules in crystal lattice.

The reactive 1 : 1 zwitterionic intermediate formed by the addition of isocyanides to dialkyl acetylenedicarboxylates was trapped with 4-arylurazoles to produce the highly functionalized pyrazolo[1,2-a][1,2,4]triazoles 5 in good yields (Table). The structures of the products 5a–h were corroborated spectroscopically (IR, 1H- and 13C-NMR), by EI-MS, and elemental analysis. A possible mechanism for this reaction is proposed (Scheme).

Solution and radical polymerization of acrylamide in the presence of potassium persulfate in D2O was investigated up to high conversion by high‐field 1H‐NMR spectroscopy. The kinetics of reaction was studied according to the data obtained from the corresponding spectra at various times during the polymerization reaction progress. Processing of the data led us to derive the rate equation of this polymerization reaction and determine the reaction order of each component in the rate equation. The order, with respect to initiator, was consistent with the classical kinetic rate equation (0.45), whereas the order with respect to monomer was greater than unity (1.49). The effect of temperature on the polymerization rate was also investigated and the activation energy of 48.4 kJ mol−1 was obtained over the temperature range of 60–75°C. Also some mechanistic studies were discussed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2007–2013, 2004

Summary. The environment-friendly one-pot three-component condensation reactions of 4-hydroxycoumarin or 4-hydroxy-6-methylpyrone, p-substituted benzaldehyde, and alkyl or aryl isocyanides to afford furocoumarines or furopyranones in water in good yields after about one hour at 75°C are reported.

Summary. Environment-friendly three component condensation reactions of cyclic 1,3-diketones, 4-nitrobenzaldehyde, and alkyl or aryl isocyanides to afford the corresponding tetrahydrobenzofuran derivatives in water in high yields within one hour are reported.

Summary. 5-Isopropylidene-2,2-dimethyl-1,3-dioxane-4,6-dione (the condensation product of Meldrum’s acid and acetone) reacts smoothly with tert-butyl isocyanide in the presence of primary or secondary amines to produce N- tert-butyl-2,2-dimethylbutyramide derivatives and/or 1- tert-butyl-4,4-dimethyl-2,5-dioxopyrrolidine-3-carboxamides in good yields.

Summary.:  A dynamic NMR effect is observed in the 13C NMR spectra of anhydrous quinophthalone (quinoline yellow) and its monohydrate in the vicinity of 47°C and 0°C, respectively, and is attributed to a restricted rotation around the polarized carbon–carbon double bond. The free energy of activation for this process in anhydrous quinophthalone and the monohydrate is 65±2 and 55±2 kJ · mol−1, respectively, in CDCl3.

The condensation product of Meldrum's acid and 4-nitrobenzaldehyde reacts smoothly with alkyl isocyanides in the presence of alcohols to produce dialkyl 2-[1-p-nitrophenyl-2-(alkylamino)-2-oxoethyl]malonates in excellent yield. This reaction provides a useful synthetic route to highly functionalized amidodiesters.

The addition of dialkyl acetylenedicarboxylates to strong CH-acids in the presence of triphenylphosphine leading to highly functionalized 1,4-diionic organophosphorus compounds is reported. These betaines possess two vicinal stereogenic centers and exist as a mixture of two diastereoisomers. Interconversion between the two diastereoisomeric forms of these 1,4-diionic compounds viaC-H proton exchange reactions of the (Ph)3P+-CH moieties, preclude their separation. The assignments of the two diastereoisomeric forms of these systems are based on the high-field 1H, 13C and 31P NMR data.

A transition-metal-free postmodification of the Groebke–Blackburn–Bienaymé (GBB) reaction for the synthesis of spiro[chromene-imidazo[1,2-a]pyridin]-3′-imine was discovered. The unusual transformation represents the first example of activation and the reaction of the imidazole carbon atom. In this postcondensational modification, KOt-Bu acts as a base, which, after the isomerization of an alkyne moiety to allene, causes the next unique nucleophilic reaction of the imidazole carbon atom that results in spirocyclic structures. The proposed reaction mechanism was confirmed based on the DFT calculations.

Pyrrole undergoes a smooth reaction with dialkyl acetylenedicarboxylates in the presence of triphenylphosphine in a mixture of water–acetone (50:50) as a solvent pathway to produce phosphorus ylides of 2-substituted pyrrole in good yield.

The 1:1 adduct produced in the reaction between tert-butyl isocyanide and dialkyl acetylenedicarboxylates was trapped by alkyl 2-fluoro-anilino-2-oxo-acetates or ethyl 2-oxo-2-(trifluoromethylanilino)-acetate to produce functionalised ketenimines in good yields. Dynamic NMR effects were observed in the 1H NMR spectra of these compounds as a result of restricted rotation around the single bond linking the aryl group to the ketenimine system. The free energy of activation (ΔG≠) for this process is 64.9–66.5 kJ mol−1.

The addition of isocyanides to dialkyl acetylenedicarboxylates in the presence of isatoic anhydride leading to highly functionalised ketenimines is reported at room temperature.

The addition of alkyl isocyanides to dialkyl acetylenedicarboxylates in the presence of phthalic anhydride derivatives leading to highly functionalised γ-spiroiminolactones is reported.

The adduct produced in the reaction between cyclohexyl isocyanide and ethyl acetylenecarboxylate was trapped by N, N′-dimethylbarbituric acid. Dynamic NMR effects were observed in the NMR spectra of these compounds and were attributed to restricted rotation around the alkyl-nitrogen single bonds and the polarised carbon–carbon double bond.

Protonation of highly reactive 1,4-zwitterionic intermediate generated in the reaction between pyridine or isoquinoline and dialkyl acetylenedicarboxylates by strong CH-acid such as 1,1,1,5,5,5-hexafluoropentane-2,4-dione, leads to a vinyl pyridinium cation derivatives, which undergo carbon centred Michael type addition with the conjugate base of the CH-acid to produce highly functionalised stable 1,4-diionic nitrogen betaines.

Protonation of the 1:1 intermediate produced in the reaction between dialkyl acetylenedicarboxylates and triphenylphosphine by ethyl 4,4,4-trifluoroacetoacetate leads to vinyltriphenylphosphonium salts: the positively charged ion reacts with the anion of ethyl 4,4,4-trifluoroacetoacetate to form ylides 5a–c, which undergo intramolecular Wittig reaction to produce 1-ethyl 2,3-dialkyl 4-(trifluoromethyl)-3-cyclobutene-1,2,3-tricarboxylate, which undergo electrocyclic ring-opening reactions in boiling toluene to produce highly electron-deficient 1, 3-dienes in fairly good yields.

The reaction of isocyanides 1with two equivalent of ninhydrin 2gives Cssymmetry dispiro iminodioxolanes 3at refluxing conditions in chloroform in fairly high yields.

Isocyanides undergo formal [1 + 4]cycloaddition with 2-acetyl-1,4-benzoquinone to afford isobenzofuran-4,7-quinone derivatives.

The highly reactive 1:1 intermediate produced in the reaction between tert-butyl isocyanide and dialkyl acetylenedicarboxylates is trapped by dialkyl 2-bromomalonates to yield the title compounds in fairly high yields.

Isocyanides undergo formal [1+4]cycloaddition with 2-acetyl-1,4-benzoquinone to afford isobenzofuran-4,7-quinone derivatives.

The highly reactive 1:1 intermediate produced in the reaction between tert-butyl isocyanide and dialkyl acetylenedicarboxylates is trapped by dialkyl 2-bromomalonates to yield the title compounds in fairly high yields.

Isocyanides undergo formal [1+4]cycloaddition with 2-acetyl-1,4-benzoquinone to afford isobenzofuran-4,7-quinone derivatives.

2-Nitro-1-nitrosoethylbenzene has been synthesized in fairly high yield and its tautomerization studied by 1H NMR spectroscopy.

The Cu(I)‐catalyzed cycloaddition of ortho‐propynyloxybenzaldehydes (I) with the pyranone (II) constitutes an efficient synthesis of the title compounds (III).

Michael‐type addition of hydroxycoumarins (I) towards β‐nitrostyrenes (II) in the presence of ammonium acetate provides access to title amino(aryl)methylenechromanediones (III) in high yields.

Ugi four‐component reaction and direct carbopalladative cyclization—Buchwald reaction sequence permits a convenient synthesis of the title compounds.

Domino Heck—Buchwald reaction of Ugi four component reaction products (I) and (IV) with aromatic amines provides access towards title oxindole derivatives (III) and (V), respectively.

The highly fluorescent products may be of interest in the field of bioorganic and medicinal chemistry.

The title reaction proceeds under mild conditions and gives the synthetically important succinimides diastereoselectively.

Reactive zwitterionic intermediates formed by the addition of catalytic N‐methylimidazole to acetylenic esters are trapped by TOSMIC (I) to give pyrroles in high yields.