Activated nitriles in heterocyclic synthesis. A novel synthesis of 1,2,4-tnazol-3-oyl nitriles

Synthesis of 1,2,4-triazoloyl nitriles via reaction of 4-phenylhydrazono-2-phenyl-2-oxazolin-5-one and 4-phenylhydrazono-2-ethoxy-2-thiazolin-5-one with active methylene nitriles was accomplished. Some of the chemical properties of the nitriles obtained are reported.     

A novel thermal rearrangement of allenic imidothioates. Formation of iminocyclobutenes

Allenic imidothioates, H₂CCC(Ph)C(SMe)NR (R = Me, t-Bu, Ph) have been obtained in good yields by reaction of 1,3-dilithiated 1-(2-propynyl)benzene with isothiocyanates and successive addition of t-butyl alcohol and methyl iodide. Heating the imidothioates at ∼120 °C gave an iminocyclobutene as the only isolated product (if R = t-Bu), a ∼4:6 mixture of a 2,3-dihydropyridine and an iminocyclobutene (if R = Me) or a 3:1 mixture of a quinoline and an iminocyclobutene (if R = Ph).     

From azides to nitriles. A novel fast transformation made possible by BrF3

[reaction: see text]. Various alkyl and aryl azides, readily obtained from halides or alcohols, were transformed into the corresponding nitriles using bromine trifluoride in moderate to good yields. The reaction is general and gives positive results with aliphatic, aromatic, cyclic, and functionalized azides. It can also be applied to the synthesis of optically active nitriles.     

A novel system for the synthesis of nitriles from carboxylic acids

A simple, mild and high yielding method for the conversion of various carboxylic acids to nitriles has been developed using diphosphorus tetraiodide in combination with ammonium carbonate at room temperature.     

Unsymmetrical Ni(II)-imidoylamidine complexes derived from a novel oxime-mediated single-pot reaction of nitriles

The neutral bisimidoylamidine (or 1,3,5-triazapentadiene) Ni(II) complexes [Ni{HN=C(R)N=C(C(6)H(4)CO)N}(2)] {R=Me, Et, nPr, iPr, (CH(2))(3)Cl}, bearing an iminoisoindolinone moiety, have been generated by a novel 2-propanone oxime-mediated single-pot reaction of phthalonitrile and nickel(II) acetate in solution of the corresponding alkylnitrile (RCN). Single-crystal X-ray diffraction analyses indicate a square-planar geometry of the imidoylamidine core. The synthesised compounds represent rare specimens of genuine unsymmetrical imidoylamidine complexes as well as their first examples generated from nitriles in a single-pot reaction.     

Continuous-flow synthesis of nitriles from aldehydes via Schmidt reaction

Using continuous-flow synthesis of nitriles by Schmidt reaction, a variety of aldehydes could be smoothly transformed into the desired nitriles in good to excellent yields. The mild reaction conditions and the flowing reaction system greatly improved the safety and make the reaction easy to scale up.     

Iodine-mediated aryl transfer reaction from arylhydrazine hydrochlorides to nitriles

An iodine-promoted, metal-, base-, and solvent-free cross-coupling reaction was developed for the synthesis of various useful secondary amides via an aryl N-addition reaction of aryl groups to cyano groups. This aryl transfer reaction proceeds with arylhydrazine hydrochlorides serving as the aryl donors. A labelling experiment shows that the N atom in the product comes from the cyano group of the nitriles, which are low in cost. A plausible radical-driven mechanism is also proposed.     

Fluoro-substituted ketones from nitriles using acidic and basic reaction conditions

Fluoro-substituted aliphatic nitriles are shown to undergo the Houben-Hoesch reactions with arenes in CF₃SO₃H to give fluoro-substituted ketones in good yields. The fluorine substituents appear to enhance the reactivities of the nitriles (and the nitrilium ion intermediates) compared to similar aliphatic nitriles. Fluoro-substituted ketones are also shown to be accessible through the reactions of organometallic reagents and fluoro-substituted nitriles.     

Synthesis of 2- and 4-imino(1,2-a)pyridopyrimidines from allenic nitriles and 2-aminopyridines

4,4-Dialkylallenyl nitriles and 2-aminopyridines give 2-alkyl-4-iminopyrido(1,2-a)pyrimidines as monohydrates in about 90% yield and 4-monoalkylallenyl nitriles similarly give 4-alkyl-2-imino(1,2-a)pyrimidines.     

Activated nitriles in heterocyclic synthesis. A novel synthesis of pyrazine derivatives

A novel synthesis of pyrazine derivatives from the reaction of α-tosyloximinonitriles with several active methylene enaminonitrile derivatives is reported. The reaction sequence is discussed.     

Functionalized oxazoles from rhodiumi-catalyzed reaction of dimethyl diazomalonate with nitriles

Rhodium(II) acetate catalyzes the reaction of dimethyl diazomalonate with nitriles to give 4-carbomethoxy-5-methoxy-1,3-oxazo1es. Oxazole formation exceeds cyclopropane formation even in cases of conjugated and non-conjugated unsaturated nitriles.     

Iodine-catalyzed one-pot synthesis of amides from nitriles via Ritter reaction

Ritter reactions of alcohols and tert-butyl acetate with various nitriles were performed using iodine as a mild and effective catalyst under heating conditions to afford the corresponding amides in good to excellent yields.     

Organocatalytic synthesis of amides from nitriles via the Ritter reaction

A simple, inexpensive, environmentally friendly, and efficient route for the synthesis of a wide variety of amides in high yields via the Ritter reaction of alcohols with nitriles has been demonstrated. Pentafluorophenyl ammonium triflate (PFPAT) is used as an organocatalyst and is air-stable, cost-effective, easy to handle, and easily removed from the reaction mixtures.