- Mild and practical method for the α-arylation of nitriles with heteroaryl halides
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A mild and transition-metal-free method for theα-arylation of a liphatic nitriles with activated heteroaryl halides was developed using NaHMDS o r KHMDS as base at ambient temperature. The key to the success of this method is generation of the nitrile anion in the presence of the heteroaryl halide. The method is applicable to both primary and secondary carbonitriles and a wide range of heteroaryl halides. Selective monoarylation was observed with primary carbonitriles. The operational simplicity and the mild reaction conditions add to the value of this methodas a practical alternative to the preparation of α-heteroaryl carbonitriles.
- Klapars, Artis,Waldman, Jacob H.,Campos, Kevin R.,Jensen, Mark S.,McLaughlin, Mark,Chung, John Y. L.,Cvetovich, Raymond J.,Chen, Cheng-Yi
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p. 10186 - 10189
(2007/10/03)
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- Fungicidal 2-aryl-2-cyano-2-(heterocyclylalkyl)ethyl-1,2,4-triazoles
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This invention relates to 2-aryl-2-cyano-2-(heterocyclylalkyl)ethyl-1,2,4-triazoles of the formula STR1 wherein Ar is an optionally substituted aryl group, Het is an optionally substituted five or six membered saturated or unsaturated heterocyclic ring containing one, two or three heteroatoms selected from oxygen, nitrogen and sulfur, or is a bicyclic unsaturated ring system containing up to ten atoms including one heteroatom selected from oxygen, nitrogen and sulfur, R is hydrogen or alkyl, n is zero or an integer of at least one, and the agronomically acceptable enantiomorphs, geometric isomers, acid addition salts and metal salt complexes thereof.
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- SRN1 Mechanism in Heteroaromatic Nucleophilic Substitution. Reactions Involving Certain Dihalogenated ?-Deficient Nitrogen Heterocycles
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Photostimulated reactions of 2,6-,2,3-, 3,5-, and 2,5-dihalopyridines (1a-e) with pinacolone potassium enolate (2) in liquid NH3 lead to facile replacement of both halogens via a modified SRN1 mechanism, which does not involve intermediate formation of monosubstitution products.The potassium salts of phenylacetonitrile (12a) and α-ethylphenylacetonitrile (12b) react with 2,6-dibromopyridine (1a) under similar conditions to afford a mixture of mono- and disubstituted products via a related SRN1 process. 4,7-Dichloroquinoline (16) undergoes radical-chain displacement of chloride from C4 with enolate 2. 2,6-Dichloropyrazine (18) and 2,3-dichloropyrazine (20) also undergo monosubstitution with 2 and diisopropyl ketone potassium enolate (22), but these reactions appear to be mainly addition-elimination (SNAr) processes.Treatment of 3,6-dichloropyridazine (27) with 22 results in addition of 22 to C4 of the substrate.Photoassisted reaction of 2,4-dichloropyrimidine (31) with 12a leads to exclusive chloride displacement from C4 via the SRN1 mechanism.
- Carver, David R.,Greenwood, Thomas D.,Hubbard, James S.,Komin, Andrew P.,Sachdeva, Yesh P.,Wolfe, James F.
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p. 1180 - 1185
(2007/10/02)
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