- Selective fluorodenitration of chloronitroaromatics
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Nucleophilic fluorination of chloronitrobenzenes shows a strong bias for fluorodenitration rather than halogen exchange.
- Beaumont, Andrew J.,Clark, James H.,Boechat, Nubia A.
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- Process for the preparation of chlorinated and fluorinated benzene compounds by selective nucleophilic fluorodenitration
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A process for the preparation of chlorinated and fluorinated benzene compounds of the general formula (1) STR1 in which R denotes --CN or --COOalkyl(C1 -C6), and X and Y each denote chlorine or fluorine, X and Y being not identical, by fluorodenitration, which comprises reacting a compound of the formula (2) STR2 in which R is defined as above, and X' and Y' each denote chlorine or nitro, X' and Y' being nor identical, with potassium fluoride in a dipolar aprotic solvent in the presence of a transfer catalyst at a temperature from about 50° C. to about 250° C.
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- Further Studies on the Synthesis of Quinazolines from 2-Fluorobenzonitriles
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Recently, we reported that appropriately substituted 2-fluorobenzonitriles undergo cyclization with guanidine carbonate to afford 2,4-diaminoquinazolines usually in good to excellent yield.This paper describes the preparation of a variety of new 2,4-diaminoquinazolines substituted at positions five or seven.In addition, the reactions of selected 2-fluorobenzonitriles with formamidine acetate or acetamidine acetate were examined.The results obtained demonstrate that the analogous 4-amino- and 2-methyl-4-aminoquinazolines can be prepared by this approach but that yields are considerably lower than when guanidine carbonate is employed as the cyclization reagent.
- Hynes, John B.,Tomazic, Alenka,Parrish, Christie A.,Fetzer, Oliver S.
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p. 1357 - 1364
(2007/10/02)
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- Displacement of Halogen of 2-Halogeno-Substituted Benzonitriles with Carbanions. Preparation of (2-Cyanoaryl)arylacetonitriles
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(2-Cyanoaryl)arylacetonitriles are obtained by displacement of halogen of 2-halobenzonitriles with phenylacetonitrile anions.The method also applies to a number of heteroaromatics with ortho-situated halogen and cyano groups and to heteroarylacetonitrile anions.The anions were generated by using potassium tert-butoxide or potassium carbonate.Calculated electron densities of the electrophilic centers reflect the reactivity in the displacement reaction.The calculations indicate that the potassium ion complexes with the cyano group of the 2-halobenzonitriles in nonpolar solvents, thus promoting competitive addition of the anion to the cyano group.Carbanions derived from acids with pKa ca. 19-23 similarly displaced the halogen of 2-halobenzonitriles.
- Bech Sommer, Michael,Begtrup, Mikael,Boegesoe, Klaus Peter
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p. 4817 - 4821
(2007/10/02)
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