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This article discusses the synthesis of N-trifluoromethyl thiocarbamates and ureas from 3-aminopyridine-derived carbamates. The authors present a new method for the synthesis of these compounds using isothiocyanates and carbonyl electrophiles. The article describes the reaction conditions and substrate scope for this synthesis, and the authors anticipate that this protocol will have numerous applications in drug discovery. The document provides procedures for the synthesis of various sulfamides derived from 3-aminopyridine, as well as information on the synthesis and characterization of various compounds using general procedures and techniques such as NMR and HRMS. The text also includes specific examples of synthesized ureas, along with their corresponding NMR and HRMS data. The supporting information for the article is available online. [Extracted from the article]

n‐Bu4NI/K2S2O8 mediated C−N coupling between aldehydes and amides is reported. A strong electronic effect is observed on the aromatic aldehyde substrates. The transformylation from aldehyde to amide takes place exclusively when an aromatic aldehyde bears electron‐donating groups at either the ortho or para position of the formyl group, while the cross‐dehydrogenative coupling dominates in the absence of these groups. Both the density functional theory (DFT) thermochemistry calculations and experimental data support the proposed single electron transfer mechanism with the formation of an acyl radical intermediate in the cross‐dehydrogenative coupling. The n‐Bu4NI/K2S2O8 mediated oxidative cyclization between 2‐aminobenzamide and aldehydes is also reported, with four quinazolin‐4(3H)‐ones prepared in 65–99 % yields. [ABSTRACT FROM AUTHOR]

n‐Bu4NI/K2S2O8 mediated transformylation from p‐anisaldehyde to primary amides is reported. The mechanistic studies suggest the reaction occurs via a single electron transfer pathway. Based on the DFT electronic structure calculations of various reaction pathways, the most plausible mechanism involves the formation of a phenyl radical cation and an arenium ion as the key intermediates. It represents the first example where p‐anisaldehyde is employed as a formyl source via a non‐metal mediated Csp2−Csp2 bond cleavage. [ABSTRACT FROM AUTHOR]

Consumers paying more attention to physical health has led to an increasing market demand for low-sugar dried fruit products. The quality of products dried via low pressure superheated steam drying (LPSSD) is not only superior to those dried via conventional hot air or vacuum drying (VD), but also has the potential to reduce sugar content. In order to elucidate the mechanism of reducing the sugar of mango slices by LPSSD and obtain low-sugar dried mango slices, the combined effect of LPSSD–VD on mango slices was studied and an evaporation experiment of a sugar solution in a low pressure superheated steam environment was performed. This study revealed that the sugar reduction of mango slices was mainly due to the superheated steam carryover phenomenon in the second half of the constant-temperature stage and the occurrence of Maillard reaction during LPSSD. The quality attributes of mango slices dried using LPSSD–VD was improved compared with LPSSD and VD. As a result, LPSSD–VD could be used to regulate the sugar content in dried fruit and provide a theoretical basis for the production of low-sugar preserved fruits. [ABSTRACT FROM AUTHOR]

8-Oxoguanine (OG) is the most common oxidatively generated nucleobase damage and can mispair with adenine (A) in Hoogsteen mode during replication. Besides introducing the G·C→T·A transversion mutation, the OG·A base pair is vulnerable to ionizing radiation and one-electron oxidation owing to the lower ionization and oxidation potentials of OG than natural DNA nucleobases. Herein, we report the formation and collision-induced dissociation (CID) of the radical cation of a model base pair consisting of nucleoside-mimicking 9-methyl-8-oxoguanine (9MOG) and 9-methyladenine (9MA). The [9MOG·9MA]•+ radical cation is formed in the gas phase by redox-separation of electrospray ionization-produced CuII-nucle-obase complexes, and its CID is examined using guided-ion beam tandem mass spectrometry. Measurement included kinetic energy-dependent dissociation product ions and cross sections, from which the product pairs of [9MOG – H]• + [9MA+H]+ (major dissociation channel) and 9MOG•+ + 9MA (minor) were detected with 0 K dissociation threshold energies of 1.8 and 1. 65 eV, respectively. The [9MOG·9MA]•+ structures were examined using density functional theory, and important conformations were all featured by complete intra-base pair proton transfer as [9MOG–H]•·[9MA+H]+. On the other hand, the production of 9MOG•++9MA in dissociation required a 9MOG•+·9MA intermediate. The results were rationalized by the discovery of a double-well potential that evolves on the reaction potential energy surface of the collisionally activated base pair, leading to the proton-transfer equilibrium of excited ([9MOG–H]•·[9MA+H]+)* ⇌ (9MOG•+·9MA)*. The combined experimental and theoretical work provides insight into the less intuitive aspects of this biologically-important, non-canonical base pair, especially its opening upon oxidative and ionization damage. [ABSTRACT FROM AUTHOR]