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Abstract Production of value-added compounds from waste materials is of utmost importance for the development of a sustainable society especially regarding their use as catalysts in industrially relevant synthetic reactions. Herein, we show the production of laccases from four white-rot fungi, which were grown on agricultural residues, specifically Trametes versicolor 11269, Pleurotus ostreatus 1020, Panus tigrinus 707 and Lentinula edodes SC-495. The produced laccases were tested on a laccase-mediator system (LMS) for the biocatalytic oxidation of the model substrate benzyl alcohol into benzaldehyde. The LMS was carried out in the presence both of tetrahydrofuran as co-solvent and of the mediator 2,2,6,6-tetramethyl-1-piperidinyloxyl (TEMPO) due to its high redox potential and its ability to perform the oxidation. Tolerance studies showed that the dialyzed solutions were able to tolerate 1% (99:1 v/v) of co-solvent, whereas a concentration of 10% v/v had a detrimental activity. Performances in the biocatalytic oxidation of laccase solutions from different purification steps were compared. Similar conversion was observed for laccase in dialysis (raw) and gel filtration (GF) product versus commercial T. versicolor laccase. The latter oxidized almost 99% of substrate while the other laccase solutions were able to reach a conversion from 91% for the laccase solution from P. tigrinus 707 after dialysis, to 50% for the laccase solution from P. ostreatus 1020 after gel filtration. This work highlights the potential of unpurified laccase solutions to be used as catalysts in synthetic reactions.

The complex structure of aminobenzylnaphthols can be easily obtained with the useful Betti reaction. These valuable compounds can give rise to chiral intermediates, that found wide application in asymmetric synthesis. 1-[(1S)-(4-Fluorophenyl)-((1′S)-1′-naphthalen-1-yl-ethylamino)-methyl]-naphthalen-2-ol 1 was treated with triflic anhydride to yield the corresponding (S,S)-triflate 2, which is a valuable intermediate in the future synthesis of aminophosphine, to be used in asymmetric catalysis. Preliminarily structural considerations based upon H(1)-NMR spectroscopy are also reported.

In the original publication [...]

Sulindac is a well-known anti-inflammatory agent, sometimes employed as an adjuvant in antitumor therapy. Due to the recent interest in sulfoximine for its potential chemotherapeutics, we decided to transform sulindac and its methyl ester into the corresponding sulfoximines to test their antitumor activity. These compounds were fully characterized. Eventually, sulindac, sulindac methyl ester and the two novel corresponding sulfoximines were tested against malignant cells of U-87 glioblastoma, MCF-7 human breast cancer, HepG2 human liver hepatocellular carcinoma, CaCo-2 human colon cancer, and HeLa human cervical cancer. Interesting preliminary results were observed that encourage new investigations in this research theme.

The Betti reaction of 2-naphthol, benzaldehyde and (S)-1-(4-nitrophenyl)ethylamine without any solvent gave the corresponding aminobenzylnaphthol, that is the (S,S)-1-(phenyl((1′-4-nitrophenyl-ethyl)amino)methyl)-2-naphthol, in good yield (56%). The absolute configuration of the title compound was attributed by NMR analysis, a procedure that is reliable if compared with the data obtained by X-ray diffraction experiments.

The solvent-free Betti reaction of 2-naphthol, 4-nitrobenzaldehyde and (S)-valine methyl ester gave the corresponding aminobenzylnaphthol of the (S,S)-2-(((hydroxynaphth-1-yl)(4′-nitrophenyl)methyl)amino)-3-methylbutanoic acid methyl ester in good yield (59%). This product was fully characterized. We observed that the racemization that occurs in some Betti reactions with (S)-valine methyl ester was absent in this reaction, and thus the predominant (S,S)-product was obtained.

Two aminobenzylnaphthols, which are representative items of the family of compounds synthesized with the Betti reaction, were investigated as antiproliferative agents against adenocarcinoma human colorectal (Caco-2) and human neuroblastoma (SH-SY5Y) cell lines, using cisplatin as a positive control. A better antiproliferative activity was recorded after 24 h of incubation for the first tested molecule, whereas the other one was more effective after 72 h of incubation. These results support the hypothesis that both of the tested aminobenzylnaphthols could potentially be endowed with a biological activity.

Chiral nonracemic aminobenzylnaphthols were obtained by a Betti multi-component reaction between 2-naphthol, aryl aldehydes and enantiopure arylethylamine. Moreover, some new aminobenzylnaphthols were synthesized by a similar reaction between 2-naphthol, aryl aldehydes and prolinol. These aminobenzylnaphthols, synthesized from different components and thus having different structural features, were tested as anti-yeast agents inhibiting Candida albicans. The effect towards the test strain was studied with a microdilution approach and three different concentrations (150, 300 and 450 µg/mL) were tested. The best results were found for the aminobenzylnaphthols obtained from 1-naphthylethylamine and from natural prolinol. The use of the two-way ANOVA highlighted the better performances of the prolinol derivative among the differently structured aminobenzylnaphthols that were screened. The activity towards C. albicans of this prolinol derivative resulted to be interesting and could represent a promising alternative to overcome the problem of the strains resistant to the traditional antifungals.