Medicinal chemistry perspectives on the development of piperazine-containing HIV-1 inhibitors

The Human immunodeficiency virus (HIV) is the causative agent of acquired immunodeficiency syndrome (AIDS), one of the most perilous diseases known to humankind. A 2023 estimate put the number of people living with HIV around 40 million worldwide, with the majority benefiting from various antiretroviral therapies. Consequently, the urgent need for the development of effective drugs to combat this virus cannot be overstated. In the realm of medicinal and organic chemistry, the synthesis and identification of novel compounds capable of inhibiting HIV enzymes at different stages of their life cycle are of paramount importance. Notably, the spotlight is on the progress made in enhancing the potency of HIV inhibitors through the use of piperazine-based compounds. Multiple studies have revealed that the incorporation of a piperazine moiety results in a noteworthy enhancement of anti-HIV activity. The piperazine ring assumes a pivotal role in shaping the pharmacophore responsible for inhibiting HIV-1 at critical stage, including attachment, reverse transcription, integration, and protease activity. This review also sheds light on the various opportunities that can be exploited to develop effective antiretroviral targets and eliminate latent HIV reservoirs. The advancement of highly potent analogues in HIV inhibitor research has been greatly facilitated by contemporary medicinal strategies, including molecular/fragment hybridization, structure-based drug design, and bioisosterism. These techniques have opened up new avenues for the development of compounds with enhanced efficacy in combating the virus.

An Efficient Inclusion Complex Based Fluorescent Sensor for Mercury (II) and its Application in Live-Cell Imaging

The formation of an inclusion complex between hydroxypropyl-β-cyclodextrin (H-CD) and 4-acetylphenyl-4-(((6-chlorobenzo[d]thiazol-2-yl)-imino)-methyl)-benzoate (L) was investigated by FT-IR, ¹H-NMR, X-ray diffraction (XRD), FT-Raman, scanning electron microscope (SEM) techniques in the solid-state, absorption and emission spectroscopy in the liquid state and the virtual state as molecular docking technique. The binding properties of the inclusion complex (H-CD: L) with cations in deionized water was observed via absorbance and photoluminescence (PL) emission spectroscopy. The fluorescence probe (H-CD: L) inclusion complex (IC) was examined for several heavy metal cations, and identified that the PL emission wavelength of the complex displayed a continuous rise in the fluorescence intensity for Hg²⁺. A linearity range of 1 × 10^-8 - 11 × 10^-8 M and limit of detection value of 2.71 × 10^-10 M was found to be achieved for the detection of Hg²⁺. This outcome proves that the inclusion complex H-CD: L would be a promising material for the development a solid-state fluorescence probe for detecting Hg²⁺. It also shows application in real sample analysis and cell imaging.

New protocols for the synthesis of 5-amino-7-(4-phenyl)-4,7-dihydro-[1,2,4]triazolo[1,5-a]pyrimidine-6-carboxylate esters using an efficient additive

This work introduces a new additive named 4,4'-trimethylenedipiperidine for the practical and ecofriendly preparation of ethyl 5-amino-7-(4-phenyl)-4,7-dihydro-[1,2,4]triazolo[1,5-a]pyrimidine-6-carboxylate derivatives. This chemical is commercially available and easy to handle. It also possesses a low melting point and a broad liquid range temperature, high thermal stability, and good solubility in water. Based on green chemistry principles, the reaction was performed in a) a mixture of green solvents i.e. water and ethanol (1:1 v/v) at reflux temperature, and b) the additive was liquefied at 65 °C and the reaction was conducted in the liquid state of the additive. High yields of the desired triazolo-pyrimidines were obtained under both aforementioned conditions. Our results demonstrated that this additive, containing 2 Lewis base sites and able to act as an acceptor-donor hydrogen bonding group, is a novel and efficient alternative to piperidine, owing to its unique properties such as its reduced toxicity, nonflammable nature, nonvolatile state, broad liquid range temperature, high thermal stability, and ability to be safely handled. Furthermore, this additive could be completely recovered and exhibited high recyclability without any change in its chemical structure and no significant reduction in its activity. The current methodology has several advantages: (a) it avoids the use of hazardous materials, as well as toxic, volatile, and flammable solvents, (b) it does not entail tedious processes, harsh conditions, and the multistep preparation of catalysts, (c) it uses a metal-free and noncorrosive catalyst, and (d) reduces the generation of hazardous waste and simple work-up processes. The most important result of this study is that 4,4'-trimethylenedipiperidine can be a promising alternative for toxic, volatile, and flammable base reagents in organic synthesis owing to its unique properties.

Source rock evaluation of Afowo clay type from the Eastern Dahomey Basin, Nigeria: insights from different measurements

The Cretaceous Afowo Formation in the Eastern Dohamey Basin is characterized by an admixture of lithofacies ranging from sandstones, claystones, shales, clays, sand/shale, and sand/clay intercalations. The sandy facies, a mix of sandstone, clay, shale, and intercalations, contain biodegraded hydrocarbons while the shales and claystones that underlie it are rich in organic matter. The hydrocarbon-bearing interval is commonly referred to as the oil sand or tar sand. In this study, Afowo clay type underlying an outcrop of the oil sand was appraised for its hydrocarbon potential with loss on ignition, thermogravimetry, and rock evaluation pyrolysis. Results obtained from loss on ignition showed that total organic matter content, a proxy to total organic carbon, for the Afowo clay type ranged from 9.410 to 38.750 wt%. The organic maturation temperature (Tmax) was determined using both thermogravimetry and rock evaluation pyrolysis (Rock–Eval). Thermogravimetric analysis produced reliable Tmax within the range of 417–424 °C for all the samples. The results from rock evaluation pyrolysis on the same samples showed that total organic carbon ranged from 0.81 to 18.46 wt% with Tmax ranging from 417 to 424 °C. It was not possible to determine Tmax for one of the samples with Rock–Eval due to a small S2 value (0.22 mg Hc/g). The variations in organic matter contents from loss on ignition agree with total organic carbon computed from rock evaluation pyrolysis; samples with high organic matter contents have corresponding high TOC values. This study demonstrates that loss on ignition and thermogravimetry could complement and augment rock evaluation pyrolysis data for petroleum source rock characterization.

An Efficient Synthesis of Pyrrolidinone Derivatives in the Presence of 1,1′-Butylenebis(3-sulfo-3H-imidazol-1-ium) Chloride

The catalytic efficiency of 1,1′-butylenebis(3-sulfo-3H-imidazol-1-ium) chloride as a sulfonic acid-functionalized ionic liquid was demonstrated for the synthesis of pyrrolidinone derivatives under mild conditions. The electronic effect of substituents on aniline derivatives was investigated. Further, a study on the structure–activity relationship of ionic liquids containing sulfonic groups for the synthesis of ethyl-2-(4-chlorophenyl)-4-hydroxy-5-oxo-1-(p-tolyl)-2,5-dihydro-1H-pyrrole-3-carboxylate was performed under optimal conditions. The results showed that the catalytic properties of ionic liquids containing two sulfonic or imidazole moieties with carbon spacers was superior to ionic liquids having one sulfonic or imidazole moiety with no carbon spacer.

Would you take blood through a venflon?

One way of saving junior doctors' time and patients' pain is to take blood samples through a venflon immediately after its insertion. This is not, however, universal practise as some believe the results, especially urea and electrolytes, are unreliable. We have surveyed junior doctors in our hospital about this practise and prospectively compared venflon and vein blood samples.

Alpha 2-adrenoceptors in human lymphocytes: direct characterisation by [3H]yohimbine binding

[3H]yohimbine, a potent and selective alpha 2-adrenergic antagonist was used to label alpha-adrenoceptors in intact human lymphocytes. Binding of [3H]yohimbine was rapid (t1/2 1.5 -2.0 min) and readily reversed by 10 microM phentolamine (t1/2 = 5 - 6 min) and of high affinity (Kd = 3.7 +/- 0.86 nM). At saturation, the total number of binding sites was 19.9 +/- 5.3 fmol/10(7) lymphocytes. Adrenergic agonists competed for [3H]yohimbine binding sites with an order of potency: clonidine greater than (-) epinephrine greater than (-) norepinephrine greater than (+) epinephrine much greater than (-) isoproterenol; adrenergic antagonists with a potency order of yohimbine greater than phentolamine greater than prazosin. These results indicate the presence of alpha 2-adrenoceptors in human lymphocytes.

Circadian variation in number and affinity of beta 2-adrenoceptors in lymphocytes of asthmatic patients

To determine whether circadian variation in adrenoceptor function might underlie the 'morning dip' in peak expiratory flow (PEF) rate and its abolition by salbutamol we measured indices of beta-adrenoceptor function (Bmax. and Kd), the ratio FEV1/FVC, and plasma cortisol at 08.00 and 18.00 hours on and off salbutamol (4 mg given orally every 4 h) in five extrinsic asthmatic patients and five normal volunteers. There was a significant circadian variation in receptor numbers (Bmax.) in both the control and asthmatic groups which was not abolished on treatment with salbutamol. Both groups appeared to compensate for loss of receptor number induced by salbutamol administration by increasing receptor affinity. For comparable combinations of drug/time, there was no significant difference between the control and asthmatic groups. We conclude that the 'morning dip' observed in asthmatic patients cannot simply be explained by changes in cell receptor number or affinity, as our results suggest that both groups have intact beta-adrenoceptor function. Nevertheless, our observations of the normal circadian rhythm has important implications for future studies of beta-adrenoceptors in asthmatic patients.