Synthesis of thiazolidine-2,4-dione tethered 1,2,3-triazoles as α-amylase inhibitors: In vitro approach coupled with QSAR, molecular docking, molecular dynamics and ADMET studies

A new series of thiazolidine-2,4-dione tethered 1,2,3-triazole derivatives were designed, synthesized and screened for their α-amylase inhibitory potential employing in vitro and in silico approaches. The target compounds were synthesized with the help of Cu (I) catalyzed [3 + 2] cycloaddition of terminal alkyne with numerous azides, followed by unambiguously characterizing the structure by employing various spectroscopic approaches. The synthesized derivatives were assessed for their in vitro α-amylase inhibition and it was found that thiazolidine-2,4-dione derivatives 6e, 6j, 6o, 6u and 6x exhibited comparable inhibition with the standard drug acarbose. The compound 6e with a 7-chloroquinolinyl substituent on the triazole ring exhibited significant inhibition potential with IC50 value of 0.040 μmol mL-1 whereas compound 6c (IC50 = 0.099 μmol mL-1) and 6h (IC50 = 0.098 μmol mL-1) were poor inhibitors. QSAR studies revealed the positively correlating descriptors that aid in the design of novel compounds. Molecular docking was performed to investigate the binding interactions with the active site of the biological receptor and the stability of the complex over a period of 100 ns was examined using molecular dynamics studies. The physiochemical properties and drug-likeliness behavior of the potent derivatives were investigated by carrying out the ADMET studies.

Influence of Adding Carbonaceous Fuels to Ionic Liquids on Propellant Properties

To make ionic liquids (ILs) accessible and economical, ethylene glycol was mixed in 1-ethyl-3-methylimidazolium-dicyanamide ([EMIm]DCA) to obtain droplets that could experimentally collide white fuming nitric acid. To investigate the ignition delay (ID) time theoretically in terms of hydrodynamics, alcohol fuels and kerosene were used as combustibles, while the intermiscibility between them and nitric acid (HNO₃) was calculated using the ternary phase-field method alongside finite element analysis. The specific impulses of blend fuels were calculated by a thermodynamic method and compared to ILs. When the droplet was ethylene glycol/[EMIm]DCA with a 2.1 mm diameter and a 1.69 m/s colliding velocity, the ID time was the shortest. Kerosene was not an applicable additive for [EMIm]DCA owing to its lower intermiscibility with ILs and HNO₃ than alcohol fuels; alcohol fuels, however, were appropriate. The concentration of ethylene glycol in the oxidizer pool increased faster than the concentration of propylene glycol, triggering more rapid hypergolic ignition in the first 50 ms. The protocols regarding the hypergolic ignition conditions were verified, i.e., the size of the droplet had to be minute when the colliding velocity was as fast as possible; this was carefully calculated using ethylene glycol. According to thermodynamic calculations, the addition of alcohol fuels can improve the specific impulse of fuels, with ethylene glycol performing the best. The feasibility of adding alcohol fuels to ILs was confirmed via experiments and thermodynamic computations, with the simulation results providing some guidance on selecting the experimental or engineering conditions or both.

Mechanochemical synthesis and structural analysis of trivalent lanthanide and uranium diphenylphosphinodiboranates

Phosphinodiboranates (H₃BPR₂BH₃^-) are a class of borohydrides that have merited a reputation as weakly coordinating anions, which is attributed in part to the dearth of coordination complexes known with transition metals, lanthanides, and actinides. We recently reported how K(H₃BP^tBu₂BH₃) exhibits sluggish salt elimination reactivity with f-metal halides in organic solvents such as Et₂O and THF. Here we report how this reactivity appears to be further attenuated in solution when the ^tBu groups attached to phosphorus are exchanged for R = Ph or H, and we describe how mechanochemistry was used to overcome limited solution reactivity with K(H₃BPPh₂BH₃). Grinding three equivalents of K(H₃BPPh₂BH₃) with UI₃(THF)₄ or LnI₃ (Ln = Ce, Pr, Nd) allowed homoleptic complexes with the empirical formulas U(H₃BPPh₂BH₃)₃ (1), Ce(H₃BPPh₂BH₃)₃ (2), Pr(H₃BPPh₂BH₃)₃ (3), and Nd(H₃BPPh₂BH₃)₃ (4) to be prepared and subsequently crystallized in good yields (50-80%). Single-crystal XRD studies revealed that all four complexes exist as dimers or coordination polymers in the solid-state, whereas ¹H and ¹¹B NMR spectra showed that they exist as a mixture of monomers and dimers in solution. Treating 4 with THF breaks up the dimer to yield the monomeric complex Nd(H₃BPPh₂BH₃)₃(THF)₃ (4-THF). XRD studies revealed that 4-THF has one chelating and two dangling H₃BPPh₂BH₃^- ligands bound to the metal to accommodate binding of THF. In contrast to the results with K(H₃BPPh₂BH₃), attempting the same mechanochemical reactions with Na(H₃BPH₂BH₃) containing the simplest phosphinodiboranate were unsuccessful; only the partial metathesis product U(H₃BPH₂BH₃)I₂(THF)₃ (5) was isolated in poor yields. Despite these limitations, our results offer new examples showing how mechanochemistry can be used to rapidly synthesize molecular coordination complexes that are otherwise difficult to prepare using more traditional solution methods.

Carbon Nanostructures Derived through Hypergolic Reaction of Conductive Polymers with Fuming Nitric Acid at Ambient Conditions

Hypergolic systems rely on organic fuel and a powerful oxidizer that spontaneously ignites upon contact without any external ignition source. Although their main utilization pertains to rocket fuels and propellants, it is only recently that hypergolics has been established from our group as a new general method for the synthesis of different morphologies of carbon nanostructures depending on the hypergolic pair (organic fuel-oxidizer). In search of new pairs, the hypergolic mixture described here contains polyaniline as the organic source of carbon and fuming nitric acid as strong oxidizer. Specifically, the two reagents react rapidly and spontaneously upon contact at ambient conditions to afford carbon nanosheets. Further liquid-phase exfoliation of the nanosheets in dimethylformamide results in dispersed single layers exhibiting strong Tyndall effect. The method can be extended to other conductive polymers, such as polythiophene and polypyrrole, leading to the formation of different type carbon nanostructures (e.g., photolumincent carbon dots). Apart from being a new synthesis pathway towards carbon nanomaterials and a new type of reaction for conductive polymers, the present hypergolic pairs also provide a novel set of rocket bipropellants based on conductive polymers.

Fire and explosion hazards of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide

The decomposition of [EMIM][Tf₂N] is endothermic in a nitrogen atmosphere but is exothermic in an air atmosphere.