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The Suzuki-Miyaura reaction is one of the most used transformations in drug research. Thus making this reaction more sustainable is of considerable current interest. Here we show that propylene carbonate (PC) can be used as a solvent for the Suzuki-Miyaura reaction. PC is one of the greenest solvents since it is synthesized under green conditions by the use of carbon dioxide in the air. All reactions proceeded well and good or excellent yields were observed for the biaryl products. Nonetheless in the case of pyridazinones, 2-hydroxypropyl- chain containing side-products were observed. Importantly, this fact allowed the isolation of several novel compounds which were generated under prominently green conditions.

Several ecdysteroid acetonides act as adjuvant chemo-sensitizing agents against various cancer cell lines, and they can be formulated to self-assembling nanoparticle (NP) pro-drugs through a hydrolysable conjugation with squalene. In the bloodstream such squalenoylated nanoparticles dissolve into low-density lipoprotein (LDL) that allows targeting tissues containing high levels of LDL-receptors. In this work, ajugasterone C 2,3;20,22-diacetonide (3) and 11α-hydroxypoststerone 2,3-acetonide (4) were squalenoylated to obtain two new ecdysteroid pro-drugs (6 and 7) and their nano-assemblies (6NP and 7NP ). A complete NMR signal assignment of 6 and 7 was achieved. Interaction of compounds 3 and 4 with chemotherapeutics was studied by the Chou-Talalay method. Compound 3 showed strong synergism with doxorubicin on a multi-drug resistant lymphoma cell line. In contrast, its nanoassembly 6NP significantly decreased the cytotoxicity of doxorubicin on these MDR cells, strongly suggesting that at least the 2,3-acetonide group was cleaved by the acidic pH of lysosomes after endocytosis of the prodrug. Further, compound 4 acted in strong antagonism with paclitaxel on MCF-7 cells and its nanoassemby 7NP also protected MCF-7 cells from the effect of paclitaxel. Our results suggest that acid-resistant A-ring substitution would be crucial to design adjuvant antitumor squalenoylated ecdysteroid prodrugs. Additionally, our results may be considered as a serendipitous discovery of a novel way to deliver cytoprotective, adaptogen ecdysteroids to healthy tissues with upregulated LDL-R.

Ethyl 4-oxo-3,4-dihydroquinazoline-2-carboxylate reacts selectively with trimethylaluminium-activated 2-amino- or 4-aminobenzoic acid ethyl esters to give the corresponding anilides without self-condensation of the aminobenzoate building blocks. After propargylation, the quinazolinones were treated with Hendrickson's reagent, but only the para-substituted ester was found to undergo the expected [4 + 2] cycloaddition reaction, affording a new Luotonin A derivative. A different regioselectivity was observed with the ortho-substituted ester which affords a benzoxazinone under identical conditions. When the ester group in the ortho-substituted intermediate is replaced with a nitrile function, the outcome of the reaction with Hendrickson's reagent depends on the absence or presence of a base (DBU), yielding either a triphenylphosphonium-substituted iminobenzoxazine or a 4-cyano-substituted Luotonin A derivative.

Baicalin is a flavone glycoside extracted from Scutellaria baicalensis, a traditional Chinese herbal medicine. Numerous pharmacological effects of baicalin were reported (e.g. antioxidant, anxiolytic); nevertheless, the most important physicochemical properties influencing the pharmacokinetic behaviour and the concomitant oral bioavailability have not yet been described in a comprehensive study. The aim of this project was to characterize the acid-base, lipophilicity, biorelevant solubility and permeability properties of the drug substance and providing scientific data to support the dosage form design. Another important objective was the comparative evaluation of six various baicalin-cyclodextrin (CD) inclusion complexes along with the creation of a suitable Drug Delivery System (DDS) for this BCS IV drug. Biorelevant profiling was carried out by NMR-pH titrations, saturation shake-flask and distribution coefficients (logP) measurements, while CD inclusion studies were fulfilled by experimental methods (phase solubility, 1H/13C NMR, 2D ROESY) and computational approaches. Due to low aqueous solubility (67.03 ± 1.60 μg/ml) and low permeability (Papp = 0.037 × 10−6 cm/s), baicalin is classified as BCS IV. The γ-CD complexation significantly increased the solubility of baicalin (~ 5 times). The most promoted chemical shift change occurred in baicalin-γ-CD complex. Computational studies showed disparate binding pattern for baicalin in case of β- and γ-CD; furthermore, the calculated complexation energy was − 162.4 kJ mol−1 for β-CD, while it was significantly stronger for γ-CD (− 181.5 kJ mol−1). The physicochemical and structural information of baicalin and its CD complexes introduced herein can create molecular basis for a promising DDS with enhanced bioavailability containing a bioactive phytopharmacon.

The HIV-1 Reverse Transcriptase (RT) is a validated and deeply explored biological target for the treatment of AIDS. However, only drugs targeting the RT-associated DNA polymerase (DP) function have been approved for clinical use. We designed and synthesised a new generation of HIV-1 RT inhibitors, based on the (3Z)-3-(2-[4-(aryl)-1,3-thiazol-2-yl]hydrazin-1-ylidene)-2,3-dihydro-1H-indol-2-one scaffold. These compounds are active towards both RT-associated functions, DNA polymerase and ribonuclease H. The structure, biological activity and mode of action of the new derivatives have been investigated. In particular, the nature of the aromatic group in the position 4 of the thiazole ring plays a key role in the modulation of the activity towards the two RT-associated functions.