Methods for Hydroxamic Acid Synthesis

New Derivatives of N-Hydroxybutanamide: Preparation, MMP Inhibition, Cytotoxicity, and Antitumor Activity

Using a novel method of N-substituted succinimide ring opening, new N-hydroxybutanamide derivatives were synthesized. These compounds were evaluated for their ability to inhibit matrix metalloproteinases (MMPs) and their cytotoxicity. The iodoaniline derivative of N1-hydroxy-N4-phenylbutanediamide showed the inhibition of MMP-2, MMP-9, and MMP-14 with an IC50 of 1-1.5 μM. All the compounds exhibited low toxicity towards carcinoma cell lines HeLa and HepG2. The iodoaniline derivative was also slightly toxic to glioma cell lines A-172 and U-251 MG. Non-cancerous FetMSC and Vero cells were found to be the least sensitive to all the compounds. In vivo studies demonstrated that the iodoaniline derivative of N1-hydroxy-N4-phenylbutanediamide had low acute toxicity. In a mouse model of B16 melanoma, this compound showed both antitumor and antimetastatic effects, with a 61.5% inhibition of tumor growth and an 88.6% inhibition of metastasis. Our findings suggest that the iodoaniline derivative of N1-hydroxy-N4-phenylbutanediamide has potential as a lead structure for the development of new MMP inhibitors. Our new synthetic approach can be a cost-effective method for the synthesis of inhibitors of metalloenzymes with promising antitumor potential.

Pyrazole: an emerging privileged scaffold in drug discovery

Pyrazole or 1H-pyrazole, a five-membered 1,2-diazole, is found in several approved drugs and some bioactive natural products. A myriad number of derivatives of this small molecule have been reported in clinical and preclinical studies for the potential treatment of several diseases. The number of drugs containing a pyrazole nucleus has increased significantly in the last 10 years. Some of the best-selling drugs in this class are ibrutinib, ruxolitinib, axitinib, niraparib and baricitinib, and are used to treat different types of cancers; lenacapavir to treat HIV; riociguat to treat pulmonary hypertension; and sildenafil to treat erectile dysfunction. Several aniline-derived pyrazole compounds have been reported as potent antibacterial agents with selective activity against methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci. Here, we discuss the pyrazole-derived drugs reported up to September 2023.

High Efficacy and Drug Synergy of HDAC6-Selective Inhibitor NN-429 in Natural Killer (NK)/T-Cell Lymphoma

NK/T-cell lymphoma (NKTCL) and γδ T-cell non-Hodgkin lymphomas (γδ T-NHL) are highly aggressive lymphomas that lack rationally designed therapies and rely on repurposed chemotherapeutics from other hematological cancers. Histone deacetylases (HDACs) have been targeted in a range of malignancies, including T-cell lymphomas. This study represents exploratory findings of HDAC6 inhibition in NKTCL and γδ T-NHL through a second-generation inhibitor NN-429. With nanomolar in vitro HDAC6 potency and high in vitro and in cellulo selectivity for HDAC6, NN-429 also exhibited long residence time and improved pharmacokinetic properties in contrast to older generation inhibitors. Following unique selective cytotoxicity towards γδ T-NHL and NKTCL, NN-429 demonstrated a synergistic relationship with the clinical agent etoposide and potential synergies with doxorubicin, cytarabine, and SNS-032 in these disease models, opening an avenue for combination treatment strategies.

Concept of Hybrid Drugs and Recent Advancements in Anticancer Hybrids

Cancer is a complex disease, and its treatment is a big challenge, with variable efficacy of conventional anticancer drugs. A two-drug cocktail hybrid approach is a potential strategy in recent drug discovery that involves the combination of two drug pharmacophores into a single molecule. The hybrid molecule acts through distinct modes of action on several targets at a given time with more efficacy and less susceptibility to resistance. Thus, there is a huge scope for using hybrid compounds to tackle the present difficulties in cancer medicine. Recent work has applied this technique to uncover some interesting molecules with substantial anticancer properties. In this study, we report data on numerous promising hybrid anti-proliferative/anti-tumor agents developed over the previous 10 years (2011–2021). It includes quinazoline, indole, carbazole, pyrimidine, quinoline, quinone, imidazole, selenium, platinum, hydroxamic acid, ferrocene, curcumin, triazole, benzimidazole, isatin, pyrrolo benzodiazepine (PBD), chalcone, coumarin, nitrogen mustard, pyrazole, and pyridine-based anticancer hybrids produced via molecular hybridization techniques. Overall, this review offers a clear indication of the potential benefits of merging pharmacophoric subunits from multiple different known chemical prototypes to produce more potent and precise hybrid compounds. This provides valuable knowledge for researchers working on complex diseases such as cancer.

Toxicity and anti-tumour activity of organotin (IV) compounds

Organotins are widely described as anti-tumor, anti-inflammatory, anti-fungal, and antimicrobial agents. In addition to their use in biomedical fields, organotins are also used in agricultural and industrial applications. These materials are more toxic than inorganic cans, which are poorly absorbed and are excreted on the surface of the can, and cause toxicity to a variety of organisms and damage the environment.This review focuses on organotin’s toxicity and uses in biomedical fields.

Bridged Piperidine Analogues of a High Affinity Naphthalene-Based P2Y14R Antagonist

High affinity phenyl-piperidine P2Y₁₄R antagonist 1 (PPTN) was modified with piperidine bridging moieties to probe receptor affinity and hydrophobicity. Various 2-azanorbornane, nortropane, isonortropane, isoquinuclidine, and ring-opened cyclopentylamino derivatives preserved human P2Y₁₄R affinity (fluorescence binding assay), and their pharmacophoric overlay was compared. Enantiomeric 2-azabicyclo[2.2.1]hept-5-en-3-one precursors assured stereochemically unambiguous, diverse products. Pure (S,S,S) 2-azanorbornane enantiomer 15 (MRS4738) displayed higher affinity than 1 (3-fold higher affinity than enantiomer 16) and in vivo antihyperallodynic and antiasthmatic activity. Its double prodrug 143 (MRS4815) dramatically reduced lung inflammation in a mouse asthma model. Related lactams 21-24 and dicarboxylate 42 displayed intermediate affinity and enhanced aqueous solubility. Isoquinuclidine 34 (IC₅₀ 15.6 nM) and isonortropanol 30 (IC₅₀ 21.3 nM) had lower lipophilicity than 1. In general, rigidified piperidine derivatives did not lower lipophilicity dramatically, except those rings with multiple polar groups. P2Y₁₄R molecular modeling based on a P2Y₁₂R structure showed stable and persistent key interactions for compound 15.

Heavy Metals Removal from Water by Efficient Adsorbents

Natural occurrence and anthropogenic practices contribute to the release of pollutants, specifically heavy metals, in water over the years. Therefore, this leads to a demand of proper water treatment to minimize the harmful effects of the toxic heavy metals in water, so that a supply of clean water can be distributed into the environment or household. This review highlights several water treatment methods that can be used in removing heavy metal from water. Among various treatment methods, the adsorption process is considered as one of the highly effective treatments of heavy metals and the functionalization of adsorbents can fully enhance the adsorption process. Therefore, four classes of adsorbent sources are highlighted: polymeric, natural mineral, industrial by-product, and carbon nanomaterial adsorbent. The major purpose of this review is to gather up-to-date information on research and development on various adsorbents in the treatment of heavy metal from water by emphasizing the adsorption capability, effect of pH, isotherm and kinetic model, removal efficiency and the contact of time of every adsorbent.

N-Alkenylation of hydroxamic acid derivatives with ethynyl benziodoxolone to synthesize cis-enamides through vinyl benziodoxolones

The stereoselective synthesis of cis-β-N-alkoxyamidevinyl benziodoxolones (cis-β-N-RO-amide-VBXs) from O-alkyl hydroxamic acids in the presence of an ethynyl benziodoxolone-acetonitrile complex (EBX-MeCN) is reported herein. The reaction was performed under mild conditions including an aqueous solvent, a mild base, and room temperature. The reaction tolerated various O-alkyl hydroxamic acids derived from carboxylic acids, such as amino acids, pharmaceuticals, and natural products. Vinyl dideuterated cis-β-N-MeO-amide-VBXs were also synthesized using deuterium oxide as the deuterium source. Valine-derived cis-β-N-MeO-amide-VBX was stereospecifically derivatized to hydroxamic acid-derived cis-enamides without the loss of stereoselectivity or reduction in the deuterium/hydrogen ratio.

Non-hydroxamate inhibitors of 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR): A critical review and future perspective

1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR) catalyzes the second step of the non-mevalonate (or MEP) pathway that functions in several organisms and plants for the synthesis of isoprenoids. DXR is essential for the survival of multiple pathogenic bacteria/parasites, including those that cause tuberculosis and malaria in humans. DXR function is inhibited by fosmidomycin (1), a natural product, which forms a chelate with the active site divalent metal (Mg²⁺/Mn²⁺) through its hydroxamate metal-binding group (MBG). Most of the potent DXR inhibitors are structurally similar to 1 and retain hydroxamate despite the unfavourable pharmacokinetic and toxicity profile of the latter. We provide our perspective on the lack of non-hydroxamate DXR inhibitors. We also highlight the fundamental flaws in the design of MBG in these molecules, primarily responsible for their failure to inhibit DXR. We also suggest that for designing next-generation non-hydroxamate DXR inhibitors, approaches followed for other metalloenzymes targets may be exploited.