An efficient and green approach is reported for the rapid synthesis of spirocyclic 2-oxindole using triethylenediamine or imidazole Brønsted acidic ionic liquids supported in Zr metal-organic framework (TEDA/IMIZ-BAIL@UiO-66) as a novel, superior and retrievable heterogeneous catalyst under ultrasonic irradiation. Heterocyclic compounds including pyrido[2,3d:6,5-d′]dipyrimidines and indeno[2′,1′:5,6]pyrido[2,3-d]pyrimidines were obtained by the one-pot condensation reaction of 6-amino-1,3-dimethyluracil, isatins and cyclic 1,3-diketone (barbituric acid or 1,3-indanedione). The reusability of the catalyst, low catalyst loading, short reaction times, excellent yields, simple work-up, and use of sonochemical procedure as a mild process and an alternative energy source are some of the advantages of this method. Furthermore, the novel heterogeneous nanocomposite was fully characterized using various techniques.

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T h r e e -C o m p o n e n t O n e -P o t S y n t h e s i s T e t r a h y d r o y r a n o [ 4 , 3 -b ] p y r r o l e sAbstract: The reactive 1:1 adduct, produced from the reaction between dialkyl acetylenedicarboxylates and 2,6-dimethylphenyl isocyanide, was trapped by methyl 2,4-dioxopentanoate to yield dialkyl 1-(2,6-dimethylphenyl)-4-methyl-2,3-dioxo-1,2,3,6-tetrahydropyrano[4,3-b]pyrrole-6,7-dicarboxylates in moderate yields.Isocyanides are compounds with an extraordinary functional group; its unusual valence structure and reactivity were discussed for over one and a half centuries. 1 Isocyanides are the only class of stable organic compounds with a formally divalent carbon. Owing to its reactivity the isocyanide group differs fundamentally from other functional groups.One of the classic themes in the chemistry of isocyanides is heterocyclic synthesis. 2,3 Among others, useful syntheses of oxazolines, 4 pyrroles, 5 imidazoles, 6 oxazoles, 7 and thiazoles 8 have been described. In continuation of our interest in the application of isocyanides in heterocyclic synthesis, 9,10 we now report the reaction between dialkyl acetylenedicarboxylates 1 and 2,6-dimethylphenyl isocyanide in the presence of methyl 2,4-dioxopentanoate. 11 This three-component one-pot synthesis leads to highly functionalized dialkyl 1-(2,6-dimethylphenyl)-4-methyl-2,3-dioxo-1,2,3,6-tetrahydropyrano[4,3-b]pyrrole-6,7-dicarboxylates 2a-c (Scheme 1).2,6-Dimethylphenyl isocyanide and acetylenic esters 1 in the presence of methyl 2,4-dioxopentanoate undergo a smooth reaction in CH 2 Cl 2 at room temperature to produce compounds 2a-c in moderate yields. A single-crystal X-ray diffraction study confirmed the identity of compound 2c. 12 An ORTEP diagram of 2c is shown in Figure 1.The mass spectra of these compounds are fairly similar and display molecular ion peaks. Any initial fragmentation involved the loss of the ester moieties. The 1 H NMR spectrum of compound 2a exhibited six single sharp lines, readily recognized as arising from methyl (d = 2.10, 2.12, and 2.67), methoxy (d = 3.06 and 3.79), and methine (d = 5.96) protons, together with a fairly complex multiplet in the aromatic region. The 13 C NMR spectrum of 2a showed twenty signals in agreement with the proposed 1,2,3,6-tetrahydropyrano[4,3-b]pyrrole structure. The 15 N NMR spectrum exhibited a signal at d = 155.8, downfield from external liquid ammonia, for the lactam nitrogen atom. The observed 15 N shift for 2a is in good agreement with the previously reported values for lactams. 13 The 1 H and 13 C NMR spectra of 2b and 2c are similar to those of 2a except for the ester groups, which exhibit characteristic signals with appropriate chemical shifts.Mechanistically, it is conceivable that the reaction involves the initial formation of a 1:1 zwitterionic intermediate 3 between 2,6-dimethylphenyl isocyanide and the acetylenic ester. Protonation of 3 by methyl 2,4-dioxopen- Scheme 1Downloaded by: University of Texas at San Antonio. Copyrighted material.

The effective and simple one-pot, three-component protocol for the synthesis of dihydropyrido[2,3- d ]pyrimidine derivatives is presented using a triethylenediamine or imidazole Brönsted acidic, ionic-liquid-supported Zr metal–organic framework (TEDA/IMIZ-BAIL@UiO-66) as a green, novel, and retrievable heterogeneous catalyst under mild conditions. The multicomponent reactions of 6-amino-1,3-dimethyl uracil, various aromatic aldehydes, and acetyl acetone were conducted under solvent-free conditions so that dihydropyrido[2,3- d ]pyrimidine derivatives can be obtained. It is possible to separate and purify the respective products easily using crystallization. We can recycle the catalysts six times without losing any major activity. Also, the characterization of the catalyst was done by energy-dispersive X-ray, field emission scanning electron microscopy, Fourier transform infrared, Brunauer–Emmett–Teller, X-ray diffraction, and thermogravimetric analysis analyses.

In this study, HMTA-BAIL@MIL-101(Cr) was prepared as a novel catalyst for the synthesis of dipyrimidine derivtives by the reaction of barbituric acids, 6-aminouracil/6-amino-1,3-dimethyl uracil, and arylaldehydes under solvent-free conditions.

An efficient, environmentally friendly and convenient route is described for the synthesis of pyrimido [4,5-d]pyrimidines by using TEDA-BAIL@UiO-66 as a novel catalyst. In this procedure, a series of pyrimido [4,5-d]pyrimidine derivatives were synthesized via the three-component reactions of 6-aminouracils, substituted aromatic aldehydes and urea or thiourea in the presence of triethylenediamine Brønsted acidic ionic liquid supported in Zr metal-organic framework (TEDA-BAIL@UiO-66) as a novel catalyst under ultrasound irradiation. Excellent yields and no tedious separation procedures are the key advantages of the present method, which produced the desired products in high yields and short reaction times. Also, the catalyst was fully characterized by energy-dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectrophotometry (FT-IR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and thermogravimetric analysis (TGA) analysis.

The reactive 1:1 intermediate produced in the reaction between dialkyl acetylenedicarboxylates and triphenylphosphine was trapped by ethyl 3-(1,2-dihydroquinoline-2-ylidene)-pyruvate to yield the isomeric dialkyl 3-ethoxy-4-oxo-5-(2-(1H)-quinolinylidene)-2-cyclopentene-1,2-dicarboxylates and trialkyl 4-(2-quinolyl)-1-cyclobutene-1,2,3-tricarboxylates in nearly 4:1 ratio.

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