10.1002/ejoc.201700588
The study systematically investigates the aromatic tetradehydro Diels-Alder (Ar-TDDA) reaction, focusing on the factors influencing the distribution of linear and angular naphthalene products. The researchers examined how the structure of the linker and the steric bulk of substituents affect product outcomes. They found that the linker’s structure plays a crucial role in determining whether the reaction yields linear or angular products. Externally activated linkers favor linear naphthalenes, while internally activated ones tend to produce angular naphthalenes. The study also explored steric hindrance effects, revealing that increased steric bulk initially favors angular products but reverses this preference beyond a certain threshold.
10.1002/anie.200460218
The research focuses on the synthesis and biological evaluation of a b-carboline-1-one mimic of the anticancer Amaryllidaceae constituent pancratistatin. The purpose of the study was to develop a more soluble analogue of pancratistatin, which has shown activity against various cancer cell lines but has poor bioavailability. The researchers hypothesized that the potency of pancratistatin and related compounds might be due to the hydrogen-bonding donor-acceptor pairing of the b-ketoamide motifs present in these compounds. They synthesized compound 5, a b-carboline-1-one analogue of pancratistatin, to test this hypothesis and evaluated its activity against a series of cancer cell lines. The synthesis involved several interesting transformations and used chemicals such as vinylaziridine, methyl indole-2-carboxylate, tosylamide, and various reagents for hydrolysis, iodolactonization, and detosylation steps. The biological evaluation showed that compound 5 had borderline activity in a murine P388 lymphocytic leukemia assay, while some intermediates in the synthesis process showed promising activities against certain cancer cell lines. The study concluded that the presence of both oxygen atoms in the methylenedioxy bridge of pancratistatin is essential for high activity, and that future analogues could be structured around different scaffolds based on the activity of intermediates like iodolactone 11. The synthesis of compound 5, with nine steps, is the shortest existing preparation of pancratistatin analogues containing the aminoinositol motif, and the researchers plan to focus on heteroatom alterations in the aromatic portion of pancratistatin for future analogues.
10.1016/S0040-4020(97)00313-X
The research study on the efficient removal of sugar O-Tosyl groups and heterocyclic halogens from purine nucleosides using sodium naphthalenide. The purpose of this research was to develop an improved strategy for the synthesis of specific nucleosides by leveraging the high reduction potential of sodium naphthalenide, which is known for its ability to cleave carbon-halogen bonds and regenerate alcohols and amines from p-toluenesulfonate esters and p-toluenesulfonamides. The study concluded that sodium naphthalenide could effectively remove 2'-, 3'-, and 5'-O-tosyl groups from the sugar moiety of nucleosides, making p-toluenesulfonyl a viable protecting group. Additionally, it demonstrated the reductive cleavage of bromo or chloro groups from the 2-, 6-, or 8-position of purine nucleosides. Key chemicals used in the process included sodium naphthalenide, p-toluenesulfonate esters, p-toluenesulfonamides, and various purine nucleosides such as adenosine and its derivatives.
10.1021/jo00126a079
The research focuses on the development of a simplified six-step synthesis method for supercryptands, which are spherical macrotricyclic ligands known for their exceptional complexing abilities, particularly with alkali metal cations like rubidium and cesium, as well as ammonium cations and organic molecules. The study aimed to improve upon the previously lengthy and complex synthesis process, making supercryptands more accessible for further study of their complexing properties. The chemicals used in this process include p-toluenesulfonamide, diamino ethers, sodium or potassium carbonate (Na2CO3 or K2CO3), lithium aluminum hydride (LiAlH4), and various diiodo compounds. The synthesis involved the formation of ditosyl-substituted cryptands, removal of tosyl protecting groups, and subsequent cyclization to form supercryptands with yields of 30-40%. The conclusions of the research indicate that this new synthetic route is efficient and provides a practical means to prepare supercryptands for more in-depth studies of their complexing properties.
10.1016/j.tetlet.2009.11.056
The purpose of this study was to achieve mild, efficient, and selective removal of the N-tosyl group, a protecting group for primary and secondary amines, under neutral and mild conditions without the use of harmful and toxic reagents. The researchers successfully carried out the deprotection using constant current electrolysis with an undivided cell equipped with a platinum cathode and a magnesium anode, in the presence of an arene mediator, such as naphthalene or biphenyl. The process resulted in the corresponding secondary amines in good to excellent yields, demonstrating the efficiency of the method and its potential as a powerful tool for the synthesis of various nitrogen-containing organic compounds. The chemicals used in this process include N,N-disubstituted p-toluenesulfonamides, platinum, magnesium, and an arene mediator, along with a supporting electrolyte, Et4NBr, in DMF solvent.
10.1039/c4cc02645d
The study presents an efficient synthetic route to produce tosyl-protected (2S)-phenyl-3-piperidone, a common intermediate for many drugs, from biomass-derived furfural. Furfural, a platform chemical derived from agricultural waste like rice straw, is transformed into the piperidone core structure through a series of reactions involving 4-methylbenzenesulfonamide, a Lewis acid catalyst, and a rhodium-catalyzed asymmetric arylation. The aza-Achmatowicz rearrangement and hydrogenation steps further convert the intermediate into the desired piperidone. The synthetic utility of this piperidone is demonstrated by synthesizing a NK1 receptor antagonist. This method is advantageous due to its short synthetic route, high yield, minimal loss of optical purity, and the use of a renewable biomass-derived starting material, addressing sustainability and environmental concerns associated with traditional methods and the disposal of agricultural waste.
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