Experimental and theoretical approving of anomeric based oxidation in the preparation of 2-sbstituted benz-(imida, oxa and othia)-zoles using [2,6-DMPy-NO₂]C(NO₂)₃ as a novel nano molten salt catalyst

Abstract

The synthesis of [2,6-DMPy-NO2]C(NO2)3 as a novel NMS and its application in the synthesis of 2-sbstituted benz-(imida, oxa and othia)-zoles via a new mechanistic approach was supported by theoretical studies.

Nicotine‐based ionic liquid supported on magnetic nanoparticles: An efficient and recyclable catalyst for selective one‐pot synthesis of mono‐ and bis‐4H‐pyrimido[2,1‐b]benzothiazoles

“…Afterward, the intermediate E is converted to the related intermediate F via anomeric based oxidation. [ 23 ] In order to confirm this goal, the model reaction was also performed under argon atmosphere and the desired product was obtained in comparable yield. Finally, elimination of water from F produces the desired products 4aa and releases the catalyst which can be used in the next catalytic cycle.…”

“…Then, Michael type addition of 2-aminobenzothiazole 1 to intermediate B in the presence of the catalyst results in iminium ion C which upon proton transfer produces intermediate D. Next, the intermediate D undergoes intramolecular cyclization in the presence of the catalyst to afford E. Afterward, the intermediate E is converted to the related intermediate F via anomeric based oxidation. [23] In order to confirm this goal, the model reaction was also performed under argon atmosphere and the desired product was obtained in comparable yield. Finally, elimination of water from F produces the desired products 4aa and releases the catalyst which can be used in the next catalytic cycle.…”

Synthesis of novel benzimidazoles and benzothiazoles via furan‐2‐carboxaldehydes, o‐phenylenediamines, and 2‐aminothiophenol using Cu(II) Schiff‐base@SiO2 as a nanocatalyst

“…Herein, according to the literature, [ 24,33,38,39 ] a plausible mechanism for the synthesis of benzimidazole in the presence of Cu(II) Schiff‐base@SiO 2 is demonstrated in Scheme 4. First, 5‐(4‐chlorophenyl)furan‐2‐carbaldehyde ( I ) was activated using Cu(II) Schiff‐base@SiO 2 .…”

“…In recent years, the syntheses of benzimidazoles and benzothiazoles were reported using a plethora of catalysts, such as metal–organic framework (MOF) MIL‐101(Cr), [ 24 ] NH 2 ‐MIL‐125(Ti), [ 25 ] MgCl 2 , [ 26 ] Ce(NO 3 ) 3 .6H 2 O, [ 27 ] copper metallovesicles (CuMVs), [ 28 ] Ni‐MCM‐41, [ 29 ] Yb(OTf) 3 , [ 30 ] H 2 O 2 /Fe(NO 3 ) 3 , [ 31 ] vanadium–salen nanoparticles supported on silica, [ 32 ] cobalt–salen complex supported on activated carbon, [ 33 ] copper nanoparticles on charcoal, [ 34 ] Co 2+ complex of [7‐hydroxy‐4‐methyl‐8‐coumarinyl]glycine ([Co(MCG)(H 2 O) 3 ]), [ 35 ] iron‐doped multi‐walled carbon nanotubes (Fe/MWCNTs), [ 36 ] chromium (III)–salen complex nanoparticles on AlPO 4 , [ 37 ] CoFe 2 O 4 @SiO 2 @PAF‐IL, [ 38 ] and 2,6‐dimethyl‐1‐nitropyridin‐1‐ium trinitromethanide [2,6‐DMPy‐NO 2 ]C(NO 2 ) 3. [ 39 ]…”

MIL‐101(Fe) hexagonal microspindle as a highly efficient, reusable and versatile catalyst for benzo‐fused heterocyclic nucleus synthesis

“…Subsequently, the catalyst is released for the next catalytic cycle (Figure a). Recently, it was proposed that the final step of the described reaction mechanism towards target molecules proceeds via an ‘anomeric‐based oxidation’ mechanism . In this case, the anomeric effect can play an effective role in the activation of the carbene site of N‐heterocyclic part to oxidize/aromatize the intermediate.…”