Aristoxazole Analogues. Conversion of 8-Nitro-1-naphthoic Acid to 2-Methylnaphtho[1,2-d]oxazole-9-carboxylic Acid: Comments on the Chemical Mechanism of Formation of DNA Adducts by the Aristolochic Acids

Abstract

2-Methylnaphtho[1,2-d]oxazole-9-carboxylic acid was obtained by reduction of 8-nitro-1-naphthoic acid with zinc-acetic acid. This naphthoxazole is a condensation product between an 8-nitro-1-naphthoic acid reduction intermediate and acetic acid and is a lower homologue of aristoxazole, a similar condensation product of aristolochic acid I with acetic acid that was previously reported. Both oxazoles are believed to arise via a common nitrenium/carbocation ion mechanism that is likely related to that which leads to aristolochic acid-DNA-adducts.

A Green Synthetic Approach towards Polyarylated Oxazoles via Iodine‐Catalyzed One‐Pot sp3 C−H Functionalization in Water: From Natural Product Synthesis To Photophysical Studies

“…Oxazole framework belongs to one of the most widely occurring scaffolds found in many pharmaceutically active compounds, and natural products which exhibit attractive biological activities. For instance antimycobacterial naturalproduct texaline, non‐steroidal anti‐inflammatory drug oxaprozin and aristoxazole, anti‐pancreatic cancer agent PC‐046 contain oxazole in their framework (Scheme ). Oxazole scaffolds also have important application in fluorescence dyes, polymers and are also essential building blocks in synthetic organic chemistry .…”

Bioactivation mechanisms of N‐hydroxyaristolactams: Nitroreduction metabolites of aristolochic acids

“…N ‐hydroxyaristolactams are formed by a four‐electron reduction process of the nitro group of the AA followed by intramolecular modifications (Priestap et al ; Priestap et al ). In this article, we investigate mechanisms underlying the genotoxicities of the N ‐hydroxyaristolactams in bacterial and human kidney cells.…”

“…It remains to be explored, whether a previously unidentified conjugation reaction(s) promotes N ‐O‐esters formation and AL‐DNA formation, or other changes in N ‐hydroxyaristolactams facilitated by oxidation or reduction by renal cytosols lead to AL‐DNA. For example, during reduction of AA, the formation of various short‐lived metabolites has been proposed, some of which, for example, oxazinone, may, theoretically, serve as precursors of electrophilic species and AL‐DNA adducts (Priestap et al ; Priestap et al ). Likewise, biotransformation of N ‐hydroxyaristolactams in cells and extracts may result in various yet to be established metabolites.…”

Synthesis of 2,5-Disubstituted Oxazoles from Arylacetylenes and α-Amino Acids through an I2/Cu(NO3)2•3H2O-Assisted Domino Sequence

“…Increasing or reducing the amount of iodine could not raise the yield, and the reaction could not be carried out without iodine (Table 1, entries 2-4). Different copper salts such as CuSO 4 , CuBr, CuO and typical Lewis acids such as ZnCl 2 , AlCl 3 were also used to analyze the effects of these additives (Table 1, entries [5][6][7][8][9][10][11]. The results show that Cu(NO 3 ) 2 •3H 2 O was best for the reaction.…”

“…Substituted oxazoles have wide applications in many pharmacologically active synthetic molecules and natural products, 1 such as tumor-inhibitor peptide laboradorin 1-2, 2 alkaloid (-)-muscoride A, 3 antibacterial inhibitor pimprinols A-C, 4 antidiabetic agent AD-5061, 5 anti-inflammatory drugs aristoxazole, 6 oxaprozin, 7 and JTE-522. 8 They are also widely used as synthetic intermediates in organic synthesis and important ligands for transition-metal catalysis.…”