Acetohydroxamic acid: a new reagent for efficient synthesis of nitriles directly from aldehydes using Bi(OTf)3 as the catalyst

Introducing a protic ionic liquid from aminoethyl piperazine and triflic acid immobilized on pectin as a reusable nanocatalyst for the selective Schmidt synthesis of nitriles

Preparation of reusable protic ionic liquid, triflic acid-immobilized aminoethyl piperazine-modified pectin (Pec-AEP-TfOH), with excellent activity and selectivity in modified Schmidt synthesis of nitriles from aldehydes and Si(CH3)3N3 has been described. The structure of the catalyst was characterized using FT-IR, XRD, FE-SEM, EDX-mapping, and TGA-DTA. The reaction demonstrated a broad substrate scope for a variety of benzaldehyde derivatives with electron withdrawing/donating substituents and heterocyclic aldehydes with yields between 85 and 96 % at room temperature. Also, the Pec-AEP-TfOH showed an excellent selectivity for the nitriles in which no formanilide was obtained. Furthermore, the Pec-AEP-TfOH revealed a remarkable chemoselectivity for aldehydes in the presence of acids or ketones. It is worth noting that TfOH as a precious superacid was immobilized for the first time in the selective Schmidt synthesis of nitriles to improve the eco-friendliness and economic efficiency of the process. Furthermore, the catalyst was cost-effective, metal-free, safe, scalable, and reusable (5 times) and its heterogeneity was confirmed by hot-filtration test.

Facile Preparation of Aryl Nitriles from Aryl Aldehydes in PEG-DME 250

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A facie and efficient method for one-pot transformation of aryl aldehydes to aryl nitriles using hydroxylamine hydrochloride and phosphorus tribromide in PEG-DME 250 is reported. The conversion of various aryl aldehydes to the corresponding aryl nitriles occurred smoothly in high yields under the present reaction conditions.

New advances in the catalysis of organic reactions by iron compounds

The review summarizes and systematizes the literature data on a new promising application area of iron compounds, that is, catalysis of organic reactions. The considered reactions include halogenation, formation of C−C bonds with the participation of various substrates, new methods for the synthesis of ethers and aromatic and heteroaromatic carboxylic acid esters, N-alkylation of aliphatic and aromatic amines and amidation of olefins and cyclopropane-containing hydrocarbons. The advances in the synthesis of quinolines and unusual cyclization reactions catalyzed by iron complexes are described.

The bibliography includes 144 references.

Aldoxime Dehydratase Mutants as Improved Biocatalysts for a Sustainable Synthesis of Biorenewables-Based 2-Furonitrile

2-Furonitrile is an interesting nitrile product for the chemical industry due to its use as intermediate in the field of fine chemicals and pharmaceuticals or as a potential sweetener, as well as due to its access from biorenewables. As an alternative to current processes based on, e.g., the ammoxidation of furfural with ammonia as a gas phase reaction running at > 400 °C, we recently reported an enzymatic dehydration of 2-furfuryl aldoxime being obtained easily from furfural and hydroxylamine. However, improving the catalytic properties of the aldoxime dehydratase biocatalyst from Rhodococcus sp. YH3-3 (OxdYH3-3) in terms of activity and stability remained a challenge. In this contribution, the successful development of aldoxime dehydratase OxdYH3-3 mutants that were generated by directed evolution and its enhanced activity toward 2-furfuryl aldoxime is reported. The mutant OxdYH3-3 N266S showed an improved activity of up to six times higher than the wild type when utilizing a substrate concentration of 50–100 mM of 2-furfuryl aldoxime.

A practical iodine-catalyzed oxidative conversion of aldehydes to nitriles

A simple and efficient method for the direct synthesis of nitriles from aldehydes using ammonium acetate as the nitrogen source, iodine as the catalyst, and tert-butyl hydroperoxide (TBHP) as the oxidant was developed.

Direct Synthesis of Nitriles from Aldehydes and Hydroxylamine Hydrochloride Catalyzed by a HAP@AEPH2-SO3H Nanocatalyst

We describe an efficient method for the direct preparation of nitriles from aldehydes and hydroxylamine hydrochloride catalyzed by sulfonated nanohydroxyapatite functionalized by 2-aminoethyl dihydrogen phosphate (HAP@AEPH2-SO3H) as an eco-friendly and recyclable solid acid nanocatalyst. In this protocol the use of a solid acid nanocatalyst provides a green, useful, and rapid method for the preparation of nitriles in excellent yields. In addition, the notable feature of this methodolgy is that the synthesized nanocatalyst can be recovered and reused five times without any noticeable loss of efficiency.