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A novel sublimable organic salt was synthesized, and its chemical structure was characterized by FTIR, 1D NMR, 2D NMR, and elemental analysis. In addition, the thermal phase transitions and thermal stability of new organic salt were investigated. The DSC and TGA results showed that the organic salt could convert into constituent molecules at

An efficient solid/slurry-state synthesis of arylidene and alkylidene malonates as versatile intermediates is developed in the presence of mesoporous poly-melamine–formaldehyde. The condensation reaction was conducted through a ball milling process as a non-conventional procedure and a greener methodology at room temperature under solvent-free conditions. The mesoporous heterogeneous catalyst could be recovered and reused ten times, and the results showed a negligible loss of catalytic activity. Various aryl- and heteroarylidene malonates, as well as dimethyl (cyclohexylidene)malonate, were isolated in good to high yields under optimal conditions. The use of hazardous reagents and solvents were minimized in the current method, and separation of catalyst and products, as well as the recovery and reusing of catalyst, were performed by cost-effective procedures. This work revealed that the synergistic effect of numerous Lewis base sites together with acceptor-donner hydrogen bonding functional groups in porous organic polymer (POP), and its high porosity plays a vital role to promote the carbon–carbon coupling reaction in the solid phase synthesis.

A new ionic liquid is synthesized, and its chemical structure is characterized by FTIR, 1D NMR and 2D NMR, and mass analyses. The thermal behavior and thermal stability of this ionic liquid are investigated. The results approved the formation of 4,4ʹ-trimethylene-N,Nʹ-dipiperidinium sulfate instead of 4,4ʹ-trimethylene-N,Nʹ-dipiperidinium hydrogen sulfate. Moreover, the synthesis of triazolo-pyrimidine derivatives was successfully conducted in the presence of new ionic liquid at room temperature under metal-free conditions, which demonstrated the catalytic efficiency of this ionic liquid. The workup was carried out without the utilization of high-cost column chromatography. After extraction of desired products, the residual ionic liquid could be recycled and reused in the next runs. New ionic liquid exhibited high catalytic activity even after fifth run with no significant change in the chemical structure.

This paper presents the efficient synthesis of 2-amino-4H-benzo[b]pyrans using mesoporous poly-melamine-formaldehyde as a polymeric heterogeneous catalyst. According to the principals of green chemistry, the reaction was performed by the planetary ball milling process at ambient and neat conditions. The heterogeneous catalyst could be reused up to five runs with no reducing of catalytic efficiency. A variety of substituted 2-amino-4H-benzo[b]pyrans were obtained in good to excellent yields under eco-friendly conditions. Other advantages of the current methodology include short reaction time, wide substrate-scope, and use of a metal-free polymeric catalyst. Also, the current method avoids the use of hazardous reagents and solvents, tedious workup and multi-step purification. This work revealed that porous organic polymers containing Lewis base sites having acceptor-donner hydrogen bonding functional groups, and high porosity could play a vital role in the promotion of the one-pot multicomponent reactions in the solid-phase synthesis.

This paper presents an ecological protocol for Knoevenagel condensation using a catalytic amount of 4,4′-trimethylenedipiperidine as a versatile, efficient, safe, commercially available, inexpensive, and recyclable organocatalyst by a ball-milling process at room temperature. The scope of the present protocol was explored and demonstrated for Knoevenagel condensation of the active methylene, such as Meldrum’s acid with various aryl and heteroaryl aldehydes. The developed protocol provides a good to excellent conversion of various aldehydes to respective Knoevenagel products in an environmentally friendly process. Furthermore, this efficient process displays a combination of the synthetic virtues of conventional Knoevenagel condensation with ecological benefits and the convenience of a facile mechanochemistry procedure.

In the present study, the catalytic efficiency of 1,1′-butylenebis(3-sulfo-3H-imidazol-1-ium) hydrogensulfate (BBSI-HSO4) as a versatile sulfonic acid-functionalized ionic liquid was demonstrated for the one-pot mechanosynthesis of pyrano[4,3-b]-pyrans using planetary ball mill at room temperature under solvent-free conditions. This efficient mechanosynthesis approach to the 4H-pyran scaffolds displays a combination of the structure–activity relationship of ionic liquids with ecological benefits of a mechanocatalytic procedure. The ionic liquid was easily recycled and reused several times with no significant loss of its catalytic activity.

A new binuclear sulfonic-functionalized ionic liquid was synthesized in two steps and its dual solvent-catalytic activity was studied for the synthesis of a variety of xanthenes under mild conditions. The simple experimental and sustainable procedure, good yield of the desired products within short reaction times, and recyclability of the ionic liquid are some advantages of the present strategy, and the current work shows the great importance of task-specific ionic liquids in organic synthesis.

A mild and efficient protocol for the one-pot synthesis of 4-amidocinnolines was developed using saccharin as a cheap and eco-friendly organocatalyst and t-butyl nitrite as a metal-free diazotization reagent. The current method has advantages such as cost effectiveness, use of the biodegradable reagents, simple experimental procedure; afford the quantitative yield of the desired products, metal- and halogen-free as well as environmentally benign conditions.

A poly(N-vinylimidazole)-catalyzed one-pot multicomponent reaction for the synthesis of 2-amino-4H-benzo[g]chromenes containing acyl group on the 4H-chromene ring has been developed. The products were obtained in generally good to excellent yields in the presence of low loading of poly(N-vinylimidazole) as a reusable basic catalyst via this synthetic strategy. Importantly, the catalyst has the unique ability of being easily separated and recycled. The products were screened for their antibacterial activity against Escherichia coli. The results of antibacterial studies showed that three 4-aroylchromene derivatives completely inhibited E. coli at 32 mg cm−3, whereas other derivatives were either moderately active or inactive up to 64 mg cm−3. Highest antimicrobial activity was observed when the phenylglyoxal hydrate was substituted with fluoro, nitro, and methoxy groups at para position.

Thermochemical conversion of guaifenesin was performed in the presence of 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4] ionic liquid at 80 °C within 2 h. After evaluating the effect of different parameters, such as protic and nonprotic solvents, temperature, reaction time, 1-butyl-3-methylimidazolium-based ionic liquids as process media, and the amount of ionic liquid, the results demonstrate that [BMIM][BF4] facilitates the conversion of guaifenesin to 3-(2-methoxyphenoxy)propanal and other novel products, while [BMIM]Cl favors C–O bond cleavage to 2-methoxyphenol (guaiacol). The ionic liquid [BMIM][BF4] was used three times without any loss of catalytic activity. Gas chromatography–mass spectrometry (GC–MS) experiments were performed in this study to reveal the guaifenesin degradation and product formation characteristics. According to the distribution of the guaifenesin conversion products, the most plausible mechanisms were proposed by using GC–MS data.

The synergistic effect of TiO2 nanotubes and ultrasonication in promoting efficient synthesis of tacrine derivatives from 2-amino-3-cyanopyridine and cyclic ketones at room temperature was investigated. In this synthesis, the synergistic effect between Lewis acid and base sites on TiO2 nanotubes and intercalation of reactants as guest molecules into TiO2 nanotubes as host nanoreactors promoted by ultrasonication was crucial to the cyclization step. The current method showed advantages such as easy recovery and recycling of nano-catalyst, simple experimental procedure, environmentally benign conditions, and good yields of the products.

The synthesis of N-methyl imines was performed in the presence of catalytic amounts of poly(4-vinylpyridine) in high yields and rapidly at room temperature by a ball milling process. This new method has some advantages including good yields for relatively unreactive carbonyl compounds and short reaction times as well as being green in terms of avoiding the use of toxic reagents and solvents. The major advantage of this process is that the catalyst can be easily regenerated and reused several times without any significant loss of activity.

1,1′-Butylenebis(3-methyl-3H-imidazol-1-ium) hydrogen sulfate as an efficient, halogen-free, and reusable binuclear Bronsted ionic liquid catalyzed the synthesis of tacrine analogues. This method has the advantages of high yield, clean reaction, and simple methodology. The structure of the products was confirmed by IR, 1H NMR, 13C NMR, MS, and elemental analysis. .

The chemoselective N-Boc protection of amines has been performed in the presence of catalytic amount of poly(4-vinylpyridinium) perchlorate at room temperature .and neat conditions. This new method has distinct advantages, including its excellent yields and short reaction times as well as being green in terms of avoiding the use of toxic catalysts and solvents. Furthermore, the catalyst can be reused and recycled several times without significant loss in its activity.

1,1′-Butylenebis(3-methyl-3H-imidazol-1-ium) dihydrogensulfate as an efficient, halogen-free and reusable binuclear Bronsted ionic liquid catalyzed the synthesis of pyrano[4,3-b]pyran derivatives at 60 °C under solvent-free conditions. This method has the advantages of high yield, clean reactions, simple methodology and short reaction time. The ionic liquid could be recycled without significant loss of activity. The structure of the compounds was confirmed by IR, 1H NMR, 13C NMR, mass and elemental analysis.

3-Methyl-1-sulfonic acid imidazolium hydrogen sulfate, an efficient, halogen-free, and reusable Bronsted ionic liquid, catalyzed the synthesis of 13-aryl-12H-benzo[f]indeno[1,2-b]quinoline-12-one derivatives by one-pot condensation of 2-naphthylamine, aromatic aldehydes, and 2H-indene-1,3-dione under solvent-free conditions. This method has the advantages of high yields, clean reaction, simplicity, and short reaction time. The catalyst can be recycled and reused four times without significant loss of activity.

A simple and facile synthesis of 12-aryl-12-hydro-5H-benzo[g]indeno[2,1-b]quinoline-6,11,13-trione derivatives was accomplished by the one-pot condensation of 2-hydroxynaphthalene-1,4-dione, aromatic aldehydes, and 2H-indene-1,3-dione under solvent-free conditions in the presence of the solid acid catalyst, poly(4-vinylpyridinium) hydrogen sulfate. This method has the advantages of high yield, clean reaction, simple methodology, and short reaction time. The catalyst could be recycled and reused four times without significant loss of activity. The structures of the novel compounds were confirmed by IR, 1H NMR, mass and elemental analysis.

N-sulfonic acid poly(4-vinylpyridinium) chloride is easily prepared by the reaction of poly(4-vinylpyridine) with neat chlorosulfonic acid. This reagent can be used as an efficient catalyst for the N-Boc protection of amines at room temperature and neat conditions. This new method consistently has the advantages of excellent yields and short reaction times. Further, the catalyst can be reused and recovered for several times.

Poly(4-vinylpyridine) (PVP) acts as an efficient and reusable catalyst for the selective and efficient trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS) and N-tert-butoxycarbonylation of amines with (Boc)2O. All reactions were performed under mild conditions in good to high yields.

Succinimide sulfonic acid (SuSA) as a stable reagent is easily prepared by the reaction of succinimide with neat chlorosulfonic acid. This compound is able to catalyze the chemoselective conversion of amines to their corresponding N-Boc protected derivatives with (Boc)2O. All reactions were performed under mild conditions, giving the desired products in good to high yields.