TY - JOUR

T1 - Aminonitrones as highly reactive bifunctional synthons. An expedient one-pot route to 5-amino-1,2,4-triazoles and 5-amino-1,2,4-oxadiazoles-potential antimicrobials targeting multi-drug resistant bacteria

AU - Il'In, Mikhail V.

AU - Sysoeva, Alexandra A.

AU - Bolotin, Dmitrii S.

AU - Novikov, Alexander S.

AU - Suslonov, Vitalii V.

AU - Rogacheva, Elizaveta V.

AU - Kraeva, Liudmila A.

AU - Kukushkin, Vadim Yu

PY - 2019

Y1 - 2019

N2 - The developed one-pot protocol to 5-amino-1,2,4-triazoles or 5-amino-1,2,4-oxadiazoles includes an interplay between aminonitrones R1C(NH2)N+(Me)O- (R1 = Alk, Ar, Het), isocyanides R2NC (R2 = Alk, Ar), Br2, and hydrazines (for the triazoles) or hydroxylamine (for the oxadiazoles). This formally four-component reaction, involving aminonitrones, isocyanides, bromine, and N-nucleophiles, proceeds very rapidly under mild conditions (10 min, 20-25 °C), and is insensitive to moisture and air (in undried CHCl3-MeOH, in air) and it gives the heterocyclic systems in good yields (up to 86%; 26 examples). The reaction scope includes aromatic-, heteroaromatic-, and aliphatic aminonitrones and also aliphatic- and aromatic isocyanides. Results of DFT calculations (M06-2X/6-311+G(d,p) level of theory) indicate that the O-nucleophilic center of bifunctional aminonitrones is more reactive than the N center; it first reacts with in situ generated R2NCBr2 to grant 2-methyl-1,2,4-oxadiazolium salts, which are then converted to the target heterocyclic systems upon treatment with hydrazines or hydroxylamine. The nature and strength of the intramolecular hydrogen bonds N-H⋯N and O-H⋯N, which significantly contribute to the total energies of different transition states and products of the nucleophilic substitution, were studied theoretically using the topological analysis of the electron density distribution within the framework of Bader's theory (QTAIM method). Several new 5-amino-3-aryl-1,2,4-triazoles and -1,2,4-oxadiazoles exhibit high antibacterial activity against multidrug-resistant bacteria strains such as Staphylococcus aureus and Klebsiella pneumoniae (MIC = 8 mg L-1).

AB - The developed one-pot protocol to 5-amino-1,2,4-triazoles or 5-amino-1,2,4-oxadiazoles includes an interplay between aminonitrones R1C(NH2)N+(Me)O- (R1 = Alk, Ar, Het), isocyanides R2NC (R2 = Alk, Ar), Br2, and hydrazines (for the triazoles) or hydroxylamine (for the oxadiazoles). This formally four-component reaction, involving aminonitrones, isocyanides, bromine, and N-nucleophiles, proceeds very rapidly under mild conditions (10 min, 20-25 °C), and is insensitive to moisture and air (in undried CHCl3-MeOH, in air) and it gives the heterocyclic systems in good yields (up to 86%; 26 examples). The reaction scope includes aromatic-, heteroaromatic-, and aliphatic aminonitrones and also aliphatic- and aromatic isocyanides. Results of DFT calculations (M06-2X/6-311+G(d,p) level of theory) indicate that the O-nucleophilic center of bifunctional aminonitrones is more reactive than the N center; it first reacts with in situ generated R2NCBr2 to grant 2-methyl-1,2,4-oxadiazolium salts, which are then converted to the target heterocyclic systems upon treatment with hydrazines or hydroxylamine. The nature and strength of the intramolecular hydrogen bonds N-H⋯N and O-H⋯N, which significantly contribute to the total energies of different transition states and products of the nucleophilic substitution, were studied theoretically using the topological analysis of the electron density distribution within the framework of Bader's theory (QTAIM method). Several new 5-amino-3-aryl-1,2,4-triazoles and -1,2,4-oxadiazoles exhibit high antibacterial activity against multidrug-resistant bacteria strains such as Staphylococcus aureus and Klebsiella pneumoniae (MIC = 8 mg L-1).

KW - COPPER CORROSION

KW - SOLID-STATE

KW - METAL-FREE

KW - DERIVATIVES

KW - GENERATION

KW - INHIBITION

KW - COMPLEXES

KW - MECHANISM

KW - SORPTION

KW - RING

UR - http://www.scopus.com/inward/record.url?scp=85075034778&partnerID=8YFLogxK

U2 - 10.1039/c9nj04529e

DO - 10.1039/c9nj04529e

M3 - Article

AN - SCOPUS:85075034778

VL - 43

SP - 17358

EP - 17366

JO - New Journal of Chemistry

JF - New Journal of Chemistry

SN - 1144-0546

IS - 44

ER -