Nitriles to Amides

Amides react ia certain cases to form ammonium salts of sulfonated amides (22). For example, treatment with ben2amide yields ammonium A/-ben2oylsulfamate [83930-12-5] C H CONHSO NH, and treatment with ammonium sulfamate yields dianmioiiiumimidodisulfonate [13597-84-17, HN(S020NH 2 Ammonium sulfamate or sulfamic acid and ammonium carbonate dehydrate Hquid or soHd amides to nitriles (27). 

Eatty amines are made by dehydration of amides to nitriles at 280—330°C, followed by hydrogenation of the nitrile over nickel or cobalt catalysts ... 

Thermolysis of tertiary and secondary alcohols with (caitxsmethoxysulfamoyi) trtethylammonium Inner salt 5 to give olefins also conversion ol amides to nitriles... 

For further dehydration, for example, of aldoximes and amides to nitriles, of alcohols to olefines, as well as the synthesis of heterocycles like oxiranes and aziridines see Section 18.5. 

In the dehydration of primary aliphatic or aromatic amides to nitriles with CDI, the CDI is activated by an excess of a reactive halide, such as allyl bromide or benzyl bromide (2 equiv. of CDI, 8 equiv. of reactive halide, refluxing CH3CN, 2-5h) [12]... 

Many methods for the dehydration of primary amides to nitriles involve the use of strong acids and/or other reagents which are incompatible with sensitive functionality. French workers have recently described an unusual, mild, efficient (64-92%) and fairly general procedure for the RCONH2 —> RCN transformation which simply involves heating a mixture of the amide, an aldehyde and formic acid under reflux in acetonitrile for 12 hours. The following observations were made ... 

New polymer-supported reagents for sulfide transfer have been developed to avoid exposure to malodorous and toxic sulfur reagents. Ley et al.15 prepared a stable aminothiophosphate polystyrene resin for the conversion of secondary and tertiary amides to thioamides in high conversion and purity (Table III, entry 11). This procedure is extremely clean and affords the desired product with short reaction times in comparison to Law-esson s reagent. In addition, the aminothiophosphate resin dehydrates primary amides to nitriles. 

Nitriles from aldoxlmes. The system trifluoroacetic anhydride and pyridine, which converts primary amides to nitriles, also converts aldoximes to nitriles. The geometrical configuration of the substrate determines the ease of dehydration (E)-Aldoximes are less reactive than (Z)-aldoximes. However, high yields can also be obtained from the former substrates if the amount of pyridine is increased or if the reaction is conducted at higher temperatures (60-65°). 

The addition of thiobenzophenone to nitrosobenzene to give N-(diphenyl-methylene)benzenamine is said to go via a cyclic intermediate that loses sulfur monoxide to give the product. A similar mechanism is invoked in the reaction of aldehydes with 5,5 -diphenylsulfilimine to give enamines or nitriles (e.g., 587). Oxa-2,3-thiazete-2-oxides are suggested as intermediates in the dehydration of aryl amides to nitriles by thionyl chloride.The reaction of Af-sulfilamines with aldehydes, which previously were suggested to give oxa-2,3-thiazetidine-2-oxides, has been shown to yield acyclic compounds. 

The adduct of DMF and dichlorophenylphosphine has been used to convert primary aromatic amides to nitriles by dehydration," as well as to synthesize 2,5-diaryl-1,3,4-oxadiazoles from A iV -diacylhydra-zides. ... 

Phosphorus nitrile chloride forms adduct (10) with DMF in the ratio 1 4, which is useful for the preparation of formamidines and azavinylogous formamidinium salts. It is supposed that the dehydration of primary amides to nitriles with (PNChls as well as the formation of 2-alkylbenzothiazoles from 2-(methylthio)anilides and (PNChls in the presence of triethylamine proceed via similar adducts." ... 

Some of these transformations were accompanied by additional reactions, e.g. formylation of the aromatic or heteroaromatic - nucleus or CH-acidic methyl groups further dehydration of amides to nitriles was observed. Adducts from amides and PCI3, sulfonyl halides or SO2CI2/SCXZI2 from which amidines can be obtained by reaction with amine derivatives (compare Section 2.7.2.5 and refs. 5 and 14) have not found wide application for this purpose. An interesting reaction is the preparation of the amidine (294 equation 158) from 7V-pentafluorophenylformamide. By thermal decomposition of the adducts from secondary amides and 7V,iV-dialkylcarbamoyl chlorides amidinium salts were synthesized from which the amidines (295 equation 159) were set free by treatment with bases. " ... 

Deoxygenation. vic-Diols are converted to alkenes via cyclic sulfates, i.e., reaction of the latter with PhjP-l2 at room temperature. This reagent combination together with imidazole can be used to transform a-hydroxy amides to nitriles. ... 

Dehydration of amides to nitriles.2 When a mixture of an amide and (1) in the ratio of 3 1 is heated at temperatures above 100°, nitriles are formed rapidly and in high yield (usually in the range 75-100 %). The dehydration can also be carried out by refluxing the reactants in a solvent (usually chlorobenzene). In many cases, a ratio of amide to (1) of 6 1 is effective. 

RCO2H, R OH, 2-chloro-l,3-dimethylimidazolinium chloride, 76-96% yield. The reagent is a powerful dehydrating agent which has a number of other uses such as the conversion of amides to nitriles, acids to anhydrides, etc." ... 

Dehydration of amides to nitriles. Lawton and McRitchie (1, 287-288) introduced the use of thionyl chloride and DMF for dehydration of amides. Merck chemists1 obtained improved yields by use of phosphoryl chloride in DMF. For... 

---