Design, synthesis and evaluations of spiro‐fused benzoxaborin derivatives as novel boron‐containing compounds

Design, synthesis, pharmacological evaluation, and in silico studies of the activity of novel spiro pyrrolo[3,4-d]pyrimidine derivatives

In the present study, spiro compounds are shown to have distinctive characteristics because of their interesting conformations and their structural impacts on biological systems. A new family of functionalized spiro pyrrolo[3,4-d]pyrimidines is prepared via the one-pot condensation reaction of amino cyclohexane derivatives with benzaldehyde to prepare fused azaspiroundecanedione and azaspirodecenone/thione derivatives. A series of synthesized spiro compounds were scanned against DPPH and evaluated for their ability to inhibit COX-1 and COX-2. All compounds exhibit significant antiinflammatory activity, and they inhibited both COX-1 and COX-2 enzymes with a selectivity index higher than celecoxib as a reference drug. The most powerful and selective COX-2 inhibitor compounds were 11 and 6, with selectivity indices of 175 and 129.21 in comparison to 31.52 of the standard celecoxib. However, candidate 14 showed a very promising antiinflammatory activity with an IC50 of 6.00, while celecoxib had an IC50 of 14.50. Our findings are promising in the area of medicinal chemistry for further optimization of the newly designed and synthesized compounds regarding the discussed structure-activity relationship study (SAR), in order to obtain a superior antioxidant lead compound in the near future. All chemical structures of the novel synthesized candidates were unequivocally elucidated and confirmed utilizing spectroscopic and elemental investigations.

Synthesis, pharmacological evaluation, DFT calculation, and theoretical investigation of spirocyclohexane derivatives

Polycyclic structures fused at a central carbon are of great interest due to their appealing conformational features and their structural implications in biological systems. Although progress in the development of synthetic methodologies toward such structures has been impressive, the stereo selective construction of such quaternary stereo centers remains a significant challenge in the total synthesis of natural products. From the computational calculations by Density Functional Theory along with the B3LYP as basis set, It is obvious that the all studied compounds are soft molecules and η varied from 0.069 for compound (10) to 0.087 for compound (15), while the compound (14) is treated as hard molecule, the value of η is 0.102, also the electronic transition within the soft compounds is easy as indicated from the △E, the compound (10) is absolute soft according to the (σ = 14.49 eV), while the compound (14) is treated as hard compounds (σ = 9.804 eV). The newly formed compounds exhibited both anti-inflammatory and antioxidant activities on HRBC homolytic and membrane stabilization and DPPH scavenging percent, respectively.

Access to Unexplored 3D Chemical Space: cis ‐Selective Arene Hydrogenation for the Synthesis of Saturated Cyclic Boronic Acids

A new class of saturated boron‐incorporated cyclic molecules has been synthesized employing an arene‐hydrogenation methodology. cis‐Selective hydrogenation of easily accessible, and biologically important molecules comprising benzoxaborole, benzoxaborinin, and benzoxaboripin derivatives is reported. Among the various catalysts tested, rhodium cyclic(alkyl)(amino)carbene [Rh‐CAAC] (1) pre‐catalyst revealed the best hydrogenation activity confirming turnover number up to 1400 with good to high diastereoselectivity. A broad range of functional groups was tolerated including sensitive substituents such as −F, −CF₃, and −silyl groups. The utility of the synthesized products was demonstrated by the recognition of diols and sugars under physiological conditions. These motifs can have a substantial importance in medicinal chemistry as they possess a three‐dimensional structure, are highly stable, soluble in water, form hydrogen bonds, and interact with diols and sugars.

Synthesis, crystal structure, DFT and molecular docking studies of N-acetyl-2,4-[diaryl-3-azabicyclo[3.3.1]nonan-9-yl]-9-spiro-4'-acetyl-2'-(acetylamino)-4',9-dihydro-[1',3',4']-thiadiazoles: A potential SARS-nCoV-2 Mpro (COVID-19) inhibitor

In this paper, we describe the synthesis and crystal structure analysis of N-acetyl-2,4-[diphenyl-3-azabicyclo[3.3.1]nonan-9-yl]-9-spiro-4′-acetyl-2′-(acetylamino)-4′,9-dihydro-[1′,3′,4′]-thiadiazole (3a) and N-acetyl- 2,4-[bis(p-methoxyphenyl)-3-azabicyclo[3.3.1]nonan-9-yl]-9-spiro-4′-acetyl-2′-(acetylamino)-4′,9-dihydro-[1′,3′,4′]-thiadiazole (3b). The title compounds 3a and 3b are characterized by 1D NMR and single crystal x-ray diffraction analysis. Non-covalent interactions in a molecule were identified by Hirshfeld surface (d_norm contacts and 2D fingerprint plot) analysis. In addition, the existence of chalcogen bond (S•••O bond) in the molecular structures (3a and 3b) are described by NCI-RDG and QTAIM analysis. NBO analysis is employed to describe the orbital interactions and electron transfer between sulfur and oxygen atoms. Molecular docking is carried out for compounds 3a and 3b with COVID-19 viral protein SARS-nCoV-2 M^pro (PDB ID: 6LU7).

Boron-Containing heterocycles as promising pharmacological agents

The incorporation of the "magic" boron atom has been established as an important new strategy in the field of medicinal chemistry as boron compounds have been shown to form various bonds with their biological targets. Currently, a number of boron-based drugs (e.g. bortezomib, crisaborole, and tavaborole) have been FDA approved and are in the clinic, and several other boron-containing compounds are in clinical trials. Boron-based heterocycles have an incredible potential in the ongoing quest for new therapeutic agents owing to their plethora of biological activities and useful pharmacokinetic profiles. The present perspective is intended to review the pharmacological applications of boron-based heterocycles that have been published. We have classified these compounds into groups exhibiting shared pharmacological activities and discussed their corresponding biological targets focusing mainly on the most potent therapeutic compounds.

Progress in the medicinal chemistry of organoboron compounds

The review aims to draw attention to the latest advances in the organoboron chemistry and therapeutic use of organoboron compounds. The synthetic strategies towards boron-containing compounds with proven in vitro and/or in vivo biological activities, including derivatives of boronic acids, benzoxaboroles, benzoxaborines and benzodiazaborines, are summarized. Approaches to the synthesis of hybrid structures containing an organoboron moiety as one of the pharmacophores are considered, and the effect of this modification on the pharmacological activity of the initial molecules is analyzed. On the basis of analysis of the published data, the most promising areas of research in the field of organoboron compounds are identified, including the latest methods of synthesis, modification and design of effective therapeutic agents.

The bibliography includes 246 references.

Spirocyclic Scaffolds in Medicinal Chemistry

Spirocyclic scaffolds are incorporated in various approved drugs and drug candidates. The increasing interest in less planar bioactive compounds has given rise to the development of synthetic methodologies for the preparation of spirocyclic scaffolds. In this Perspective, we summarize the diverse synthetic routes to obtain spirocyclic systems. The impact of spirocycles on potency and selectivity, including the aspect of stereochemistry, is discussed. Furthermore, we examine the changes in physicochemical properties as well as in in vitro and in vivo ADME using selected studies that compare spirocyclic compounds to their nonspirocyclic counterparts. In conclusion, the value of spirocyclic scaffolds in medicinal chemistry is discussed.