An efficient and convenient method for the synthesis of 1-hydroxyalkylphosphonium salts is described. Reactions were carried out at room temperature, in a short time, and without chromatography for product isolation. The properties of the obtained phosphonium salts were examined and discussed.
View Article and Find Full Text PDFThe number of cancer-related diseases is still growing. Despite the availability of a large number of anticancer drugs, the ideal drug is still being sought that would be effective, selective, and overcome the effect of multidrug resistance. Therefore, researchers are still looking for ways to improve the properties of already-used chemotherapeutics.
View Article and Find Full Text PDFis an ethnobotanically significant plant with a relatiwely high content of spilanthol. Due to its broad spectrum of activity, including anti-inflammatory, antioxidant, analgesic, antifungal, and bacteriostatic properties, it is considered a valuable bioactive natural product. In addition, spilanthol as its main bioactive component inhibits facial muscle contractions, making it an attractive ingredient in anti-wrinkle and anti-aging cosmetics.
View Article and Find Full Text PDFFor several decades, natural products have been widely researched and their native scaffolds are the basis for the design and synthesis of new potential therapeutic agents. Betulin is an interesting biologically attractive natural parent molecule with a high safety profile and can easily undergo a variety of structural modifications. Herein, we describe the synthesis of new molecular hybrids of betulin via covalent linkage with an alkyltriphenylphosphonium moiety.
View Article and Find Full Text PDF-acyliminium-type cations are examples of highly reactive intermediates that are willingly used in organic synthesis in intra- or intermolecular α-amidoalkylation reactions. They are usually generated in situ from their corresponding precursors in the presence of acidic catalysts (Brønsted or Lewis acids). In this context, 1-aminoalkyltriarylphosphonium derivatives deserve particular attention.
View Article and Find Full Text PDFA novel method for chemo-enzymatic Baeyer-Villiger oxidation of cyclic ketones in the presence of supported ionic liquid-like phase biocatalyst was designed. In this work, multi-walled carbon nanotubes were applied as a support for ionic liquids which were anchored to nanotubes covalently by amide or imine bonds. Next, lipases B from , or were immobilized on the prepared materials.
View Article and Find Full Text PDFPentacyclic lupane-type triterpenoids, such as betulin and its synthetic derivatives, display a broad spectrum of biological activity. However, one of the major drawbacks of these compounds as potential therapeutic agents is their high hydrophobicity and low bioavailability. On the other hand, the presence of easily transformable functional groups in the parent structure makes betulin have a high synthetic potential and the ability to form different derivatives.
View Article and Find Full Text PDFNaturally occurring pentacyclic lupane triterpenoids such as betulin (1) or betulinic acid (2) and their synthetic derivatives display a broad spectrum of biological activities and, therefore, have been the subject of great interest. However, the use of these compounds as potential therapeutic agents is limited by their low bioavailability, high hydrophobicity, and insufficient intracellular accumulation. In this context, research on modifications of the parent structures that will improve their pharmacokinetic properties is particularly important.
View Article and Find Full Text PDFRaw vegetable oil from was subjected to oxidative treatment to enhance its viscosity. The oxidation processes were carried out in the presence of -hydroxyphthalimide with or without supercritical CO₂ as a solvent. Four spectroscopic techniques (Raman, UV-VIS, FT-IR, NMR) were applied to assess the chemical changes taking place during the oxidation.
View Article and Find Full Text PDFA convenient approach has been developed to α-aminoalkylidenebisphosphonates and their asymmetric phosphonyl-phosphinyl and phosphonyl-phosphinoyl analogues by α-phosphonylation, α-phosphinylation or α-phosphinoylation of 1-(N-acylamino)alkylphosphonates, that, in turn, are easily accessible from N-acyl-α-amino acids. Effective electrophilic activation of the α-position of 1-(N-acetylamino)alkylphosphonates was achieved by electrochemical α-methoxylation of these compounds in methanol, mediated with NaCl, followed by displacement of the methoxy group with triphenylphosphonium tetrafluoroborate to give hitherto unknown 1-(N-acetylamino)-1-triphenylphosphoniumalkylphosphonate tetrafluoroborates. The latter compounds react smoothly with trialkyl phosphites, dialkyl phosphonites or alkyl phosphinites in the presence of Hünig's base and methyltriphenylphosphonium iodide in a Michaelis-Arbuzov-like reaction to give the expected alkylidenebisphosphonates, 1-phosphinylalkylphosphonates or 1-phosphinoylalkylphosphonates, respectively, in good yields.
View Article and Find Full Text PDFA variety of N-(1-methoxyalkyl)amides or carbamates react readily with sodium aryl sulfinates in the presence of triphenylphosphonium tetrafluoroborate or bromide in CHCl3 under mild conditions to give 1-(N-acylamino)alkyl sulfones in good yields. A combination of this reaction with the recently described electrochemical decarboxylative α-methoxylation of N-acyl-α-amino acids to give N-(1-methoxyalkyl)amides in the presence of 3-(1-piperidino)propyl-functionalized silica gel (SiO2-Pip) enables an effective two-pot transformation of N-acyl-α-amino acids to 1-(N-acylamino)alkyl sulfones. Alternatively, N-(1-methoxyalkyl)amides can be obtained by electrochemical α-methoxylation of either N-alkylamides, lactams, or N-alkylcarbamates.
View Article and Find Full Text PDFThe diagnostic values of the following three spectral criteria for the configuration of N-acyl-alpha,beta-dehydro-alpha-amino acid esters were examined: (i) the proton at the beta-position at the double bond of a Z-isomer is shielded if compared with the respective E-isomer (delta(beta)Z < delta(beta)E); (ii) the proton at the nitrogen atom is shielded in a Z-isomer in comparison with the corresponding E-isomer (delta(NH)Z < delta(NH)E); and (iii) changing of the solvent from CDCl3 to deuterated trifluoroacetic acid (TFA) causes shielding of the H(beta) vinylic proton of an E-isomer or deshielding of the respective proton of the Z-isomer (delta(CDCl3)E > delta(TFA)E or delta(CDCl3)Z < delta(TFA)Z). The investigations were based on a set of 22 (Z)- and (E)-N-acyl-alpha,beta-dehydro-alpha-amino acid esters of diverse structures, with aliphatic, aromatic and heteroaromatic substituents at the vinylic beta-carbon; most of the examined compounds were hitherto unknown. The application of the substituent effect additivity rule given by Pascual et al.
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