Densely Functionalized 2‐Methylideneazetidines from Nitrodienic Building Blocks

Tavani, Cinzia; Bianchi, Lara; Giorgi, Gianluca; Maccagno, Massimo; Petrillo, Giovanni

doi:10.1002/ejoc.201701467

Cited by 8 publications

(6 citation statements)

References 49 publications

(19 reference statements)

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“…Conjugated nitrobutadienes deriving from the ring‐opening of nitrothiophenes are once more proving as powerful building blocks for the synthesis of heterocycles within overall ring‐opening/ring‐closing processes . Nitrogen nucleophiles readily participate in aza‐Michael‐type additions, which are generally driven to the final products by aromatization via nitrous acid elimination …”

Section: Discussionmentioning

confidence: 99%

“…We recently studied the behaviour of the same highly functionalized nitropenta‐ ( 2 ) or nitrobutadienes ( 3 ) (Scheme ) toward primary amines as nucleophiles, developing an original access to 2‐methyleneazetidines (from 2) and pyrroles (from 3). The present research is a further, significant insight in the amine/nitrodiene coupling, combining the double N‐nucleophile represented by 1 with multifaceted electrophiles as 2 and 3 .…”

Section: Introductionmentioning

confidence: 99%

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2‐Aryl‐3‐Vinyl Substituted Imidazo[1,2‐a]pyridines and Fluorescent Electrocyclization Derivatives therefrom

et al. 2020

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A collection of 2-aryl-3-vinylimidazo[1,2-a]pyridines, substituted on the pyridine ring and/or the aryl substituent, can be obtained by reaction of 2-aminopyridines with properly substituted nitrobutadienes, originated by an initial ring opening of a nitrothiophenic precursor. Although the aza-Michael addition of 2-aminopyridine on a nitrovinyl moiety is the starting point of classic approaches to imidazopyridines, the final structures generated herein are the result of a cascade process made possible by the particular functionalization on the conjugated systems. Beside the general interest inherent to the pharmacologically versatile imidazo[1,2-a]pyridine structural motif, the substituents present in the obtained compounds allow specific synthetic elaboration to e. g. polycyclic fluorescent heterocycles.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

2‐Aryl‐3‐Vinyl Substituted Imidazo[1,2‐a]pyridines and Fluorescent Electrocyclization Derivatives therefrom

et al. 2020

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“…The title compounds were obtained according to the procedure reported in Scheme 1 [ 12 ], which, starting from nitropentadienoates in turn derived from a common nitrothiophenic precursor ( Scheme 1 ), resulted in general efficiency and applicability. Briefly, the ring-opening of the thiophenic precursor 27 by pyrrolidine produces the nitroenamine 28 , from which the aryl pentadienoates 29 and 30 can be conveniently obtained.…”

Section: Resultsmentioning

confidence: 99%

“…The starting nitrothiophene 27 , the 5-pyrrolidin-1-ylpentadienoate 28 , all the 2-methylthio- and 2-methylsolfonyl-5-arylpentadienoates 29 and 30 have been already described [ 12 , 30 ]. Two new substrates, the 2-methylthio and 2-methylsolfonyl-5-cyclohexylpentadienoates ( 29e and 30e , respectively), were prepared following the same procedure, and their characterization is reported below.…”

Section: Methodsmentioning

confidence: 99%

“…Two new substrates, the 2-methylthio and 2-methylsolfonyl-5-cyclohexylpentadienoates ( 29e and 30e , respectively), were prepared following the same procedure, and their characterization is reported below. Synthesis and characterization of azetidines 5 – 9 , 12 – 14 have been already reported; [ 12 ] for the new azetidines 10 , 11 , 15 – 26 , obtained following the same procedure, the characterization is reported below.…”

Section: Methodsmentioning

confidence: 99%

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Densely Functionalized 2-Methylideneazetidines: Evaluation as Antibacterials

et al. 2021

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Twenty-two novel, variously substituted nitroazetidines were designed as both sulfonamide and urethane vinylogs possibly endowed with antimicrobial activity. The compounds under study were obtained following a general procedure recently developed, starting from 4-nitropentadienoates deriving from a common β-nitrothiophenic precursor. While being devoid of any activity against fungi and Gram-negative bacteria, most of the title compounds performed as potent antibacterial agents on Gram-positive bacteria (E. faecalis and three strains of S. aureus), with the most potent congener being the 1-(4-chlorobenzyl)-3-nitro-4-(p-tolyl)azetidine 22, which displayed potency close to that of norfloxacin, the reference antibiotic (minimum inhibitory concentration values 4 and 1–2 μg/mL, respectively). Since 22 combines a relatively efficient activity against Gram-positive bacteria and a cytotoxicity on eucharyotic cells only at 4-times higher concentrations (inhibiting concentration on 50% of the cultured eukaryotic cells: 36 ± 10 μM, MIC: 8.6 μM), it may be considered as a promising hit compound for the development of a new series of antibacterials selectively active on Gram-positive pathogens. The relatively concise synthetic route described herein, based on widely available starting materials, could feed further structure–activity relationship studies, thus allowing for the fine investigation and optimization of the toxico-pharmacological profile.

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