Microwave-assisted selective and efficient synthesis of 1,3,5-triazinyl mono and bisureas

Ruiz‐Carretero, Amparo; Ramírez, José Ramón; Sánchez-Migallón, Ana; Hoz, Antonio de la

doi:10.1016/j.tet.2014.01.043

Cited by 12 publications

(5 citation statements)

References 52 publications

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“…The tertbutyl groups are disordered. Similar intramolecular hydrogen bonds have already been found in 2-pyridylthioureas, triazinylureas, and -thioureas by either 1 H NMR spectroscopy or X-ray crystallography [54][55][56][57]. The spectral properties of azacyclic thioureas 5 in CDCl 3 differ from those of Takemoto's catalyst 3, NH signals of which are not visible at ambient temperature in the same solvent due to chemical exchange, but can be resolved at low temperature, where the presence of two monomeric conformers and two dimeric associates is revealed [58].…”

Section: Resultssupporting

confidence: 79%

2-Amino-1,3,5-triazine chemistry: hydrogen-bond networks, Takemoto thiourea catalyst analogs, and olfactory mapping of a sweet-smelling triazine

2015

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The chemistry of 4,6-dialkyl-2-amino-1,3,5-triazines with bulky alkyl substituents was investigated and their use as building blocks for preparing chiral thiourea organocatalysts explored. Reaction of ammonia with 4,6-di-tert-butyl-2-chloro-1,3,5-triazine gave 4,6-di-tert-butyl-1,3,5-triazin-2-amine which formed extended hydrogenbond networks in the solid state according to X-ray crystallography. Selected heterocyclic amines were converted to isothiocyanates, and the latter reacted with (S,S)-2-(dimethylamino)cyclohexylamine to give enantiopure 1-hetaryl-3-[2-(dimethylamino)cyclohexyl]thioureas, with hetaryl representing either 4,6-dimethyl-1,3-diazin-2-yl, 4,6-diisopropyl-1,3,5-triazin-2-yl, or 4,6-di-tert-butyl-1,3, 5-triazin-2-yl groups. These compounds are structural analogs of Takemotos's chiral thiourea organocatalysts (1-[3,5-bis(trifluoromethyl)phenyl]-3-[(1S,2S)-2-(dimethylamino)cyclohexyl]thiourea) with an aza-aryl instead of the 3,5-bis(trifluoromethyl)phenyl group. They feature a strong intramolecular N-H to N-1 hydrogen bond, as shown by X-ray crystallography of 1-(4,6-di-tert-butyl-1,3,5-triazin-2-yl)-3-[2-(dimethylamino)cyclohexyl]thiourea in the solid state and by 1 H NMR spectroscopy of all derivatives in CDCl 3 solution, which prevents them from acting as bifunctional organocatalyst. In the reaction of 4,6-di-tertbutyl-2-chloro-1,3,5-triazine with ammonia, 4,6-di-tertbutyl-2-ethoxy-1,3,5-triazine was identified as side-product displaying a mildly sweet, floral odor that is unusual for a 1,3,5-triazine. Analogs ([35) of 4,6-di-tert-butyl-2-ethoxy-1,3,5-triazine were prepared to define the important structural factors of the olfactophore. Graphical abstract N N N H N tBu tBu N S H Me 2 N N N N NH 2 tBu tBu

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Section: Resultssupporting

confidence: 79%

2-Amino-1,3,5-triazine chemistry: hydrogen-bond networks, Takemoto thiourea catalyst analogs, and olfactory mapping of a sweet-smelling triazine

2015

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“…When the reaction time increased, the O‐alkylated isomer was already formed and the desired product was found at low yield (5–8 %). In a second attempt, the reaction was performed at 120 °C for 1 hour, adding a few drops of DMF to make a heterogeneous reaction mixture, demonstrated to work better for microwave reactions . In this case, the major products were the N‐alkylated derivative accompanied by the O‐alkylated isomer.…”

Section: Resultsmentioning

confidence: 99%

Impact of Chirality on Hydrogen‐Bonded Supramolecular Assemblies and Photoconductivity of Diketopyrrolopyrrole Derivatives

Militzer

Nishimura

Ávila‐Rovelo

et al. 2020

Chemistry A European J

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Hydrogen bonds can efficiently guide the self-assembly of organic materials, enabling to tune the properties of the aggregation processes. In the case of p-conjugated materials, several parameters such as temperature, concentration and solvent can be used to modify the aggregation state while tuning the optoelectronic properties. Chirality can be included within the impacting parameters due to the differences in molecular packing. Here, chiral and achiral thiophene-capped diketopyrrolopyrrole derivatives were designed and synthesized containing amide bonds, with the aim to study the interplay between chiral assemblies and their stabilization throughh ydrogen-bonding. Differences in aggregation properties were observed with spectroscopy and microscopy,a nd ac ontactless microwave-based technique was used to study their intrinsic chargec arrierm obility.T he positive role of hydrogen-bonding has been highlighted and the differences between chiral and achiral compoundsh ave been elucidated.

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“…[53] In addition to the solid heterogeneous catalyst, the microwave irradiation (MWI) technique is another ecofriendly green chemistry tool for multicomponent organic synthesis with its unique advantages, the supply of energy directly to the reactive sites and made the reaction more dynamic with short reaction times, simple workup, high yields, improved selectivity, and clean reaction pathways compared to that of the conventional procedures. [19,[54][55][56][57][58][59] El-borai et al have been reported the multicomponent microwave irradiated synthesis of pyrazolo [3,4-b]pyridines in the acetic acid medium. [60] Salama et al have been developed a simple, efficient, and eco-friendly p-TSA as the catalyzed microwave-assisted procedure for the synthesis of bis(tetrahydrodipyrazolo [3,4-b:4 0 ,3 0 -e]pyridines) derivatives.…”

Section: Introductionmentioning

confidence: 99%

Green synthesis and anticancer activity of tetrahydrodipyrazolo[3,4‐b:4′,3′‐e]pyridines catalyzed by phospho sulfonic acid

Chinthaparthi

Chittiboena²,

Jorepalli

et al. 2021

Journal of Heterocyclic Chem

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Biologically portent/significant tetrahydrodipyrazolo[3,4‐b:4′,3′‐e]pyridines are synthesized by an efficient green synthesis of various aldehydes with 3‐methyl‐1H‐pyrazol‐5(4H)‐one in ammonium acetate using phospho sulfonic acid as a solid catalyst under microwave‐assisted interaction under solvent‐free conditions at 70°C. This methodology is easy to handle and get good to excellent yields. Later the potential in vitro antiproliferation of the titled compounds is evaluated. Among all the titled compounds, 4s and 4t showed the most potent anticancer potentiality on the used cancer cell lines of SK‐BR‐3 and HeLa (IC50 = 10.70 ± 0.27 and 12.58 ± 0.38, and 19.38 ± 0.32 and 21.55 ± 0.41 μg/mL for SK‐BR‐3 cells lines and HeLa cells lines, respectively), which were comparable to the positive control.

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Microwave-assisted selective and efficient synthesis of 1,3,5-triazinyl mono and bisureas

Cited by 12 publications

References 52 publications

2-Amino-1,3,5-triazine chemistry: hydrogen-bond networks, Takemoto thiourea catalyst analogs, and olfactory mapping of a sweet-smelling triazine

2-Amino-1,3,5-triazine chemistry: hydrogen-bond networks, Takemoto thiourea catalyst analogs, and olfactory mapping of a sweet-smelling triazine

Impact of Chirality on Hydrogen‐Bonded Supramolecular Assemblies and Photoconductivity of Diketopyrrolopyrrole Derivatives

Green synthesis and anticancer activity of tetrahydrodipyrazolo[3,4‐b:4′,3′‐e]pyridines catalyzed by phospho sulfonic acid

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