The work reports synthesis of 15 novel 3-((dicyclohexylamino)(substituted phenyl/heteryl)methyl)-4-hydroxy-2H-chromen-2-one derivatives 4 (a-o) as potential antimicrobial agents in solvent-free condition using Triethyl ammonium sulphate [Et₃NH][HSO₄] as an efficient, eco-friendly and reusable catalyst. Compared to other methods, this new method consistently has advantages, including excellent yields, a short reaction time, mild reaction conditions and catalyst reusability. The heterocyclic compound Coumarin, is associated with diverse biological activities of immense importance. Due to the presence of coumarin moiety in various pharmaceutically active compounds, we planned the green synthesis of a series of 15 novel compounds containing coumarin moiety coupled with dicyclohexyl rings by an eco-friendly ionic-liquid mediated protocol at room temperature by stirring. The structures of the synthesized compounds were confirmed by spectral characterization such as IR, 1H NMR, 13CNMR and Mass spectral studies. All the synthesized compounds 4 (a-o) were evaluated for anti-fungal and antibacterial activities and have exhibited promising antimicrobial activity.

Synthesis of fragrances, i.e. methyl esters and lactones of cyclic ketones, starts from cyclic vinyl ketones. These react with hydrogen cyanide in the presence of basic catalyst. Formed keto nitriles undergo a reduction of keto group in secondary hydroxy group in the next steps and process is followed by functionalization of cyano group in carboxy or alkoxycarbonyl group. The order of both processes can be exchanged. The final lactonization carry out between hydroxy and (funcionalized) carboxy group under acidic conditions.The functionalization of cyano group and subsequent lactonization take place as a one-pot process. This innovative process is simpler and cheaper and provides products in very good yields and purity, which allows further processing in the synthesis of the final products.

In this study we analyzed the behavior of N-mesylnitroindoles acting as electrophilic dienophiles in polar Diels-Alder reactions joint to isoprene as nucleophilic diene. The analysis was developed considering the experimental results when microwave irradiation with toluene or protic ionic liquids as solvents were used. In a similar way, the free solvent conditions were analyzed. These results were compared with the ones of conventional heating and it was found that the reactions under microwave irradiation are better than those developed in thermal conditions.

Considering the mechanism study, a unique and notably asynchronous transition state was found. We can note that, in the presence of an ionic liquid, the charge transfer is higher in relation with free solvent conditions. Based on the vibration frequencies, the microwave effect looks to be independent of the solvent used.

As a consequence of the theoretical study we can conclude that for these reactions the free solvent condition and protic ionic liquids as solvent offer similar results under microwave irradiation. However the solvent-free condition is far more favorable to environmental sustainability.

The development of multichromophoric systems able to achieve efficiently excitation energy transfer (EET) from donors to covalently linked acceptor chromophores (i.e., molecular cassettes) has gained great interest in the last few years, since they are extremely useful in the development of advanced materials for outstanding photonic technologies (including optoelectronics), such as solar harvesting, fluorescence microscopy or biomolecular probing.¹

On the other hand, the emission at longer wavelengths has important applications in Medicine, and thus it is called “the biological or therapeutic window”: In the 650-1000 nm region autofluorescence, and absorption by water, tissues and cells are minimized, and there is less light scattering. This means that deeper penetration by incident laser light can be achieved.²

In our group we have introduced a new design for the achievement of energy transfer in molecular cassettes. This design is based on spiranic O-BODIPY having a polyarene as the donor moiety.³ Based on this new design, we have developed a series of O-BODIPY dyes showing cassette behavior and emitting in the red region of the spectrum (see Figure 1).

References:

1. For example see: Yuan, L.; Weiying, L.; Zheng, K.; Zhu, Z. Acc. Chem. Res. 2013, 46, 1462; Huang, X.; Han, S.; Huang, W.; Sanyang, H.; Xiaogang, L. Chem. Soc. Rev. 2013, 42, 173.
2. Lu, H.; Mack, J.; Yang, Y.; Shen, Z. Chem. Soc. Rev. 2014, 43, 4778.
3. Sánchez-Carnerero, E. M.; Gartzía-Rivero, L.; Moreno, F.; Maroto, B. L.; Agarrabeitia, A. R.; Ortiz, M. J.; Bañuelos, J.; López-Arbeloa, Í.; de la Moya, S. Chem. Commun. 2014, 50, 12765-12767 and references cited therein.

Circularly polarized luminescence (CPL) is a chiroptical phenomenon consisting of the differential emission of right and left circularly polarized light by chiral systems (such as molecules, ionic pairs, polymers, metal complexes, supramolecular aggregates). The interest of CPL is due to the resolution provided by the circular polarization of the light, which allows the development of smarter photonic materials for useful technologies, such as 3D displaying, information storage and processing, communication of spin information (spintronics), or bioimaging (for example, ellipsometry-based tomography).^1,2

In our Group, we have demonstrated that conformationally flexible bis(BODIPY)s are a good platform for the development of smart CPL-SOMs (single organic molecules enabling CPL).² We present in this communication synthetic strategies for the modification of the parent structure, directed to the optimization of the CPL properties: (1) Introduce sterical hindrance in the flexible bridge, in order to modify the dihedral angle in the induced helix and (2) Explore new positions at which the bridge connecting both chromofores can be attached.

References:

1. Sánchez-Carnerero, E. M.; Agarrabeitia, A. R.; Moreno, F.; Maroto, B. L.; Muller, G.; Ortiz, M. J.; de la Moya, S. Chem.-Eur. J. 2015, 21 (39), 13488-13500.

2. Ray, C.; Sánchez-Carnerero, E. M.; Moreno, F.; Maroto, B. L.; Agarrabeitia, A. R.; Ortiz, M. J.; López-Arbeloa, Í.; Bañuelos, J.; Cohovi, K. D.; Lunkley, J. L.; Muller, G.; de la Moya Cerero, S. Chem.-Eur. J. 2016, 22, 8805-8808 and references cited therein.

The reactions of phloroglucinol with α,β-unsaturated dinitriles (or malononitrile and carbonyl compounds) lead to the formation of hitherto unknown 2,8-diamino-5-hydroxy-4H,10H-pyrano[2,3-f]chromene-3,9-dicarbonitriles. The reaction conditions and the structure of the products were studied in details.

Tetraalkynyl stannanes were reacted with aryl iodides and bromides under Stille conditions to give diaryl acetylenes and/or diaryl diacetylenes. The reaction conditions, scope and limitations of the proposed method are discussed.

The Mannich-type reaction of N-methylmorpholinium 4-aryl-3-cyano-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolates with 2-R-propanals (ocean propanal, isobutyraldehyde) and primary aromatic amines afforded 7-aryl-2-R-2-methyl-3-arylamino-5-oxo-2,3,6,7-tetrahydro-5Н-thiazolo[3,2-a]pyridine-8-carbonitriles in modest yields; the structure of a key compound was confirmed by X-ray crystal structure analysis. The mechanism of the reaction is discussed.

The reaction of D-(–)-pantolactone with ammonia leads to the formation of D-pantoamide, which reacts with Ас₂О and HClO₄ to give 5-[2-(acetoxy)-1,1-dimethylethyl]-2-methyl-4-oxo-4,5-dihydro-1,3-oxazolium perchlorate. The obtained 2-methyl-1,3-oxazolium perchlorate readily reacts with aromatic aldehydes to afford 2-(2-arylvinyl)-1,3-oxazolium perchlorates. The plant protecting properties of the obtained compounds were studied. We found that 2-(2-arylvinyl)-4-oxo-4,5-dihydro-1,3-oxazolium perchlorates are effective as antidotes towards herbicide 2,4-D but have no plant growth activity.

The mild Radziszewski oxidation of  3-aryl-2-cyanoacrylamides with H₂O₂–NaOH (or H₂O₂–Na₂CO₃) system leads to the formation of oxirane-2,2-dicarboxamides in good yields. The reactions and structure of the obtained products were studied. The aminolysis of the oxirane-2,2-dicarboxamides effected by primary amines occurs in keeping with Krasusky rule to afford 2-(1-R-amino-ethyl)-3-aryl-2-hydroxymalonamides or tartronamide.We found that 3-(4-methoxyphenyl)oxirane-2,2-dicarboxamide exhibited moderate activity both as plant growth regulator and 2,4-D antidote.