Synthesis of Substituted Oxazoles from <i>N</i>‐Benzyl Propargyl Amines and Acid Chlorides

Primary amines are activated by copper(I)-based Lewis acid promoters in an A3-coupling one-pot solventless reaction with aldehydes and phenylacetylene for the synthesis of secondary propargylamines. The reaction is promoted by a CuSO4/NaI system, a practical precursor of the in situ generated effective CuI/I2 system, that worked well, but only in a restricted number of examples. Substitution of I2 with CeCl3·7H2O in a one-pot two-step reaction provided good yields and a wider applicability, with the added value given by a safer procedure.

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“…Spectroscopic data in agreement with literature. 44 IR: 2926, 2852, 1487, 1443, 1068, 1027, 755, 683 cm -1 .…”

Section: N-benzyl-4-methyl-1-phenylpent-1-yn-3-amine (4f)mentioning

confidence: 99%

“…Spectroscopic data in agreement with literature. 44 IR: 2955, 2863, 1480, 1439, 1097, 1031, 755, 692 cm -1 . Benzyl-1-cyclohexyl-3-phenylprop-2-yn-1-amine (4h) Method A: yield: 0.152 g (50%); Method B: yield: 0.227 g (75%); oil.…”

Section: N-benzyl-44-dimethyl-1-phenylpent-1-yn-3-amine (4g)mentioning

confidence: 99%

Activation of Primary Amines by Copper(I)-Based Lewis Acid Promoters in the Solventless Synthesis of Secondary Propargylamines

et al. 2019

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“…23 Also, alkylideneoxazoline has been known to be isomerized to oxazole by acid. 24 Finally, the substitution of phenyliodonium group of Int-E by AcOH and/or the reductive elimination of PhI 25,26 would give the target oxazoles 2. Accordingly, the introduction of deuterium in the formation of d1-2a from 1a (Scheme 5) would depend on (i) the deuteration of Int-G by AcOD or (ii) the addition of AcOD to iodonium ylide Int-D, both steps of which would be involved in the case of d2-2a.…”

Section: Scheme 5 H/d Exchange Experimentsmentioning

confidence: 99%

Metal-free syntheses of oxazoles and their analogues based on λ3-iodane-mediated cycloisomerization/functionalization reactions or [2+2+1] cycloaddition type reactions

Saitô¹

2017

Arkivoc

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As a metal-free construction of oxazoles and furans concomitant with the introduction of oxygen functional groups or fluorine atoms into the side chains, we have developed λ 3 -iodane-mediated cycloisomerization/functionalization reactions of propargyl compounds. In these reactions, aryl-λ 3 -iodane ArI(X)Y works not only as a donor of heteroatomic functional groups but also as an activator of carbon-carbon triple bonds. Therefore, this methodology is not required any transition metal catalysts, which are frequently used in previous methods. Furthermore, this methodology can be extended to λ 3 -iodane-mediated [2+2+1] cycloaddition type reactions of alkynes, nitriles and heteroatoms for metal-free formation of oxazoles and imidazoles.

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“…Propargylamines, are the components of many bioactive intermediates, 1 and are widely used for the preparation of nitrogen-containing compounds, such as pyrazines, oxazoles, and pyrroles. 2 The preparation of propargylamines has attracted interest in the fields of medicinal chemistry and organic synthesis.…”

Section: Introductionmentioning

confidence: 99%

Amidoxime fibers-copper–catalyzed cross-dehydrogenative coupling of N,N-dimethylanilines and aromatic terminal alkynes

Gao

Tao

et al. 2021

Journal of Chemical Research

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A heterogeneous Cu(II)-AOFs catalyst, Cu(II) supported on amidoxime fibers (AOFs), is successfully applied to the cross-dehydrogenative coupling of aromatic terminal alkynes and N,N-dimethylanilines to form propargylamines. The Cu(II)-AOFs catalyst shows high catalytic activity with the yields of the corresponding propargylamines reaching 90% at 70 °C for 4 h without the protection of an inert gas. The Cu(II)-AOFs coordinate with the imine ion intermediate generated during the reaction, making the coupling facile. X-ray photoelectron spectrometer, scanning electron microscope, and energy dispersive X-ray spectroscopy results show that Cu(II) successfully coordinates with N and O atoms on the surface of the fibers with the mutual conversion between monovalent and divalent Cu in the Cu-AOFs being the catalytically active center. The catalyst can be recycled more than four times, and the catalytic activity is not obviously reduced. This process represents a new pathway for the formation of propargylamines using a Cu(II)-AOFs catalyst.

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Synthesis of Substituted Oxazoles from N‐Benzyl Propargyl Amines and Acid Chlorides

Cited by 24 publications

References 43 publications

Activation of Primary Amines by Copper(I)-Based Lewis Acid Promoters in the Solventless Synthesis of Secondary Propargylamines

Activation of Primary Amines by Copper(I)-Based Lewis Acid Promoters in the Solventless Synthesis of Secondary Propargylamines

Metal-free syntheses of oxazoles and their analogues based on λ3-iodane-mediated cycloisomerization/functionalization reactions or [2+2+1] cycloaddition type reactions

Amidoxime fibers-copper–catalyzed cross-dehydrogenative coupling of N,N-dimethylanilines and aromatic terminal alkynes

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