Twisted Intramolecular Charge-Transfer State Addition to Electron-Poor Olefins.

When electron-rich arylpyrrolinium salts are irradiated with ultraviolet light in the presence of Michael acceptors, the pyrrolinyl and aryl fragments add to the activated and polarized double bond in a regioselective manner, forming two C-C bonds and fragmenting the substrate. In this paper, we present a model for this intriguing reaction, supported by spectroscopy and computational analyses, and provide evidence for rectifying previously misassigned structures. We postulate that the photochemical reaction is inefficient because the reaction between the twisted intramolecular charge-transfer state and the olefin competes with fluorescence from this state upon photon absorption. We also discuss the practical advantages of performing this photochemical reaction in a continuous flow setup. Additionally, we explore several subsequent reactions that allow us to further modify the products of the photochemical step, ultimately leading to the creation of new chemical structures.

One-pot, regiospecific assembly of (E)-benzamidines from δ- and γ-amino acids via an intramolecular aminoquinazolinone rearrangement.

The efficient generation of novel, N-linked benzamidines resulting from a regiospecific rearrangement of quinazolinones is described. This methodology study explored reaction parameters including the effect of changing solvent and temperature, as well as varying electronic substituents on the structural core. The transformation was extensively optimized in terms of reaction conditions and scope, resulting in a protocol that consistently affords diversely functionalized amidines in high yield. The process permits regional structural derivatization that was previously inaccessible, and the multistep process was also reduced to a telescoped, five-step sequence that efficiently affords pharmacologically unique (E)-benzamidoamidines from N-BOC protected γ- and δ-amino acids.

Metabolomic analysis reveals novel isoniazid metabolites and hydrazones in human urine.

Isoniazid (INH) is a first-line drug for tuberculosis control; the side effects of INH are thought to be associated with its metabolism, and this study was designed to globally characterize isoniazid metabolism. Metabolomic strategies were used to profile isoniazid metabolism in humans. Eight known and seven novel INH metabolites and hydrazones were identified in human urine. The novel products included two hydroxylated INH metabolites and five hydrazones. The two novel metabolites were determined as 2-oxo-1,2-dihydro-pyridine-4-carbohydrazide and isoniazid N-oxide. Five novel hydrazones were produced by condensation of isoniazid with keto acids that are intermediates in the metabolism of essential amino acids, namely, leucine and/or isoleucine, lysine, tyrosine, tryptophan, and phenylalanine. This study enhances our knowledge of isoniazid metabolism and disposition and may offer new avenues for investigating INH-induced toxicity.