Nitriles silver oxide

Isothiazole-3-carboxylic acid and its 4-bromo derivative have been obtained by oxidation of the corresponding aldehydes with silver oxide. They form acid chlorides, esters, and amides. The amides may be dehydrated to give the corresponding nitriles. ... 

The Wohl degradation can be considered to consist of two steps (a) the elimination of the acetyl and nitrile groups by the action of ammonia or ammoniacal silver oxide, and (b) the formation of the diacetamide compound. The formation of the latter was explained by Wohl on the basis of the intermediate formation of oIde%do-D-arabinose... 

The diacetamide compounds were regularly obtained in all degradations employing ammonia with or without silver oxide until Hockett and Chandler applied the method to hexaacetyl-D-gluco-D-flruZo-heptono-nitrile (XLIX) and obtained a monoacetamide derivative that was identified as iV-acetyl-D-glucofuranosylamine (L). The furanose structure of L was established by lead tetraacetate oxidation. They... 

An elimination of the nitrile and the acetyl group united to carbon 2, leaving intact the other acetyls, was achieved by WohP by treatment of tetraacetyl-L-arabononitrile (LIX) with silver oxide and a very small... 

D-Ardbinoae. Tetraacetyl-D-arabononitrile was prepared by Deu-lofeu and degraded to triacetyl-D-erythrose and D-erythrose diacetamide by ammonia-silver oxide. Hockett and Maynard improved the yield of the nitrile and by hydrolysis of D-erythrose diacetamide with 0.6 N sulfuric acid obtained D-erythrose as a sirup from which methyl D-ery-throside was prepared. 

D-Fucose (Rhodeose). Voto6ek obtained tetraacetyl-D-fucononitrile in 25% yield by treating D-fucose oxime with sodium acetate-acetic anhydride. The nitrile, degraded with ammonia and silver oxide, yielded 5-desoxy-D-lyxose diacetamide in 40% yield. The diacetamide compound was hydrolyzed with 5% hydrochloric acid and the 5-desoxy-D-lyxose was obtained in solution and characterized as the p-bromo-phenylosazone. Hydrolysis of the diacetamide compound with 6 N sulfuric acid was realized by Voto6ek and Valentin and the 5-desoxy-D-lyxose was isolated as a sirup. 

D-Glucose. WohP obtained pentaacetyl-n-glucononitrile in 40% yield by the action of sodium acetate-acetic anhydride. The nitrile when treated with ammonia-silver oxide gave a 47 % yield of n-arabinose diacetamide. Hydrolysis of the diacetamide derivative with 6 N sulfuric acid produced crystalline n-arabinose in 50-60 % yield. The process was improved by Neuberg and Wohlgemuth, who obtained n-arabinose in an over-all yield of 34.7 % of the n-glucose employed. 

The lower amines have been oxidized in similar yields to nitriles at silver oxide and copper oxide anodes Activation of the electrode by deposition of a nickel hydroxide oxide layer is less essential than with alcohols due to the higher reactivity... 

Later,5,6 the presence of silver oxide was shown to be unnecessary. The reaction was also conducted in methanolic media, and 1,1-bis-(acetamido)-l-deoxy-L-threitol7 (8) and l,l-bis(acetamido)-l-deoxy-D-erythritol8 (10) were obtained in that medium from 2,3,4,5-tetra-O-acetyl-L-xylono- (7) and 2,3,4,5-tetra-O-acetyl-D-arabinono- (9) nitriles, respectively. 

WOHL DEGRADATION. Method for the conversion of an aldose into an aldose with one less carbon atom by the reversal of the cyanohydrin synthesis. In the Wohl method, the nitrile group is eliminated by treatment with ammoniacal silver oxide. 

As a result of the ring stability of 1,2-benzoselenazoles, ozonolysis of 3-styryI-l,2-benzoselenazole (11) at -30 °C afforded 57% of l,2-benzoselenazo e-3-carbaldehyde (12). Silver oxide oxidation of (12) gave a high yield of l,2-benzoselenazole-3-carboxylic acid (13) which was converted into the amide (14). The amide (14) can be dehydrated to give the nitrile (15). Formation of 3-amino-l,2-benzoselenazole (16) through a Curtius reaction has been reported. The 1,2-benzoselenazole derivative (1) on ozonolysis affords a low yield of the aldehyde (12). 

Valuable, however, is the anodic oxidation of primary amines in basic aqueous media at silver oxide, copper oxide, or, more effectively, at nickel hydroxide electrodes to form the nitriles IX in good to excellent yields [6-11]. In this case the primary step in the reaction mechanism is the hydrogen atom abstraction at C(a) by the in situ generated nickel oxide hydroxide, which is formed at about 0.63 V (vs NHE) ... 

A hydroxamoyl chloride reacts with a C—C double bond of a 1,4-quinone in the presence of silver oxide as base and oxidant. The chemistry of heterocyclic quinones has been reviewed [2947, 3650]. Addition of a nitrile oxide (review of reactions [B-43,2115]) across the a,i -double bond of a butenolide leads to a new fused isoxazole ring. Cycloheptatriene undergoes a [6 + 2]n-cycloaddition at the 2,7-positions when it is stirred at room temperature for 4 days with nitrosoben-zene [2875]. 

Aryl carboxamides can be converted to the respective nitriles by treatment with silver oxide (Ag20) and iodoethane in benzene under non-acidic conditions in good yields of 50-93% [1144],... 

General procedure. Nitriles from carboxamides [1144] A solution of the carboxamide (5 mmol) in dry benzene (50 mL), containing silver oxide (1.8 g, 7.7 mmol) and powdered 4 A molecular sieves (5.0 g) was stirred in the dark at 25 °C for 12 h. lo-doethane (0.86 g, 0.44 mL, 5.5 mmol) was then added, and the mixture was heated to reflux under argon for 17 h. The cooled solution was then Altered (Celite) and the filtrate was concentrated under reduced pressure. Purification was accomplished by chromatography on silica gel, eluting with hexane and ethyl acetate in varying proportions. 

The degradation procedure devised by Wohl 188) is essentially the reverse of the cyanohydrin synthesis. It involves the removal of the cyanide group from the acetylated nitriles, which in turn are formed from the oximes by application of the usual acetylation procedures. In the original process, the cyanide group was eliminated by the action of ammoniacal silver oxide. Under these conditions, the diacetamide compound of the low-er sugar results, and the free sugar is obtained from it by acid hydrolysis. 

Silver(ll) oxide, present on a silver anode in aqueous alkali, will also cany out the oxidation of primary amines to nitriles. Oxidation of the intermediate imine at the silver anode is however relatively slow so that hydrolysis to the aldehyde becomes an important side reaction [97], a-Amino acids give nitriles in good yields at the silver(li) oxide electrode. 

Various metal nitrates, represented by silver nitrate, sensitize photopolymerization of AN, methaciylonitrile, a-chloroacrylonitrile, croto-nitrile and methyl methacrylate. The efficiency of photosensitization runs nearly parallel to the ease of reduction of the metal ion. Although there is little doubt that the monomer plays some role in the photochemical process, it is rather difficult to decide whether the primary act is direct oxidation of the monomer or electron transfer between metal ion and nitrate anion. 

Sodium cyanide solution dissolves certain metals (I) with absorption of oxygen, e.g.. gold, silver, mercury, lead, and (2) with evolution of hydrogen, e.g.. copper, nickel, iron. zinc, aluminum, magnesium and solid sodium cyanide, when heated with certain oxides, e.g.. lead monoxide PhO. stannic oxide SnO.. yields the metal of the oxide, e.g.. lead. tin. respectively. and sodium cyanate NaCNO. Two classes of esters arc known, cyanides or nitriles, and isocyanides, isonitriles or carbylatnincs. the latter being very poisonous and of marked nauseating odor... 

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