Methantheline Bromide

Xanthenes are an important class of heterocycles in medicinal chemistry due to their diverse pharmacological properties. These tricyclic aromatic compounds, characterised by a dibenzo[b,e]pyran core with an oxygen atom at their central position, have gained significant attention for their extensive applications. Beyond pharmaceuticals, xanthenes are widely used in textiles, food industries, electro-optical devices, dyes, and bioimaging agents. Xanthene derivatives, particularly 9-substituted xanthenes, exhibit a wide range of biological activities, including antiparasitic, antibacterial, antileishmanial, cytotoxic, neuroprotective, and photophysical effects, making them valuable in drug discovery. The xanthene scaffold is present in various bioactive natural compounds such as mulgravanols A and B, hermannol, (+)-myrtucommulone D, homapanicones A and B, blumeaxanthene II, and acrotrione. Clinically relevant xanthene-based drugs include propantheline bromide (antimuscarinic), methantheline (antispasmodic), and phloxine B (photosensitiser in antimicrobial therapy). Thus, various synthetic approaches have been developed for the construction of xanthenes, with ultrasound-assisted green methodologies gaining prominence. Ultrasound technique offers advantages over conventional methods, including higher yields, faster reaction rates, and improved selectivity under milder conditions. This review comprehensively explores the ultrasound-assisted synthesis of functionalised xanthene derivatives as an eco-friendly alternative. To the best of our knowledge, this is the first in-depth review focusing on the green methodology under ultrasound irradiation.

Pyrolysis of methane using molten metal catalysts in bubble column reactors presents a cleaner and coking-free alternative for hydrogen production from natural gas due to its lack of direct CO₂ emissions.Bubble column reactors overcome coking as the byproduct carbon material floats to the top due to its lower d. with respect to the molten metal and can be collected by phys. means.Typically, the catalysts used in these systems consist of a low-melting-point solvent metal such as Sn or Bi, along with a higher m.p. active component such as Ni.In this study, we present a first-principles investigation that explores the impact of a third component, a promoter, on the reactivity of a Bi-Ni molten alloy.Specifically, we examine Al and Cu as promoters and compare their effects.Unlike previous literature that mostly relies on static nudged elastic bands and free-energy-based calculations, we develop a comprehensive ab initio mol. dynamics-based protocol to provide a detailed account of the reaction mechanism.Our direct rate calculations reveal that, overall, including either promoter at 10 or 20% leads to a better performance than using an unpromoted Ni-Bi binary alloy.To overcome the intrinsic difficulties associated with rate calculations, we have performed a large number of ab initio mol. dynamics calculations and have analyzed the H dissociation times for each reaction step involved in the reaction mechanisms.Our findings reveal that overall Cu outperforms Al as a promoter under the simulation conditions employed.To better understand this outcome, we carefully examined each dissociation event and identified several intriguing trends, including the contrasting contributions of Al and Cu to reactivity.We have further rationalized our results with the help of simple descriptors such as binding energy and partial Bader charges in binary metal clusters and have found that the strength of the interaction of different metal species in the alloy with one another and the product fragments in the immediate neighborhood of the reaction as well as relative partial charges correlate very well with dissociation time data.The anal. methods developed in this study will be used in future research, enabling the screening of a broader range of promoters and facilitating the design of these promising energy production systems.