Nitriles from oximes

Preparation of acetylated nitriles from oximes with pyridine-acetic anhydride. Penta-acelyl-n-glucosaminonitrile. One gram of D-glucosamine oxime hydrochloride was treated with 6 ml. of pyridine and 6 ml. of acetic anhydride and kept at 20° until solution had occurred. The solution was then concentrated and the crystalline residue was recrystallized from ethanol yield 1.8 g. (84%), m. p. 126°. 

Preparation of propionylated nitriles from oximes. Pentapropionyl-n-glucono-nitrile. Twenty grams of n-glucose oxime was dissolved in 100 ml. of pyridine and 100 ml. of propionic anhydride was added the solution was heated for one hour at 100° and was then poured into ice water. The sirupy precipitate was extracted with ether, and the ether solution was washed with sodium bicarbonate solution (5%) and with water. The ether was evaporated and the remaining sirup was distilled at 0.001... 

Benzoyl chloride Nitriles from oximes with simultaneous benzoylation... 

Poly phosphoric acid Nitriles from oximes... 

Normal and abnormal Beckmann rearrangement 1,2,4-Oxadiazoles from glyoximes Nitriles from oximes... 

Acetylation of phenols with simultaneous formation of nitriles from oximes s. U, 547... 

Preparations of nitriles from oximes and bydrazones, which are ketone derivatives, are found in Section 195,... 

The preparation of nitriles from oximes and other compounds are presented here. 

Nitriles and oximes are considered together because of common features. Both functions are reduced to primary amines, both undergo coupling reactions to secondary amines, and both are subject to reductive hydrolysis. These similarities arise from a common intermediate, an imine. The imine is... 

DipolarCycloaddition Reactions. The 1,3-dipolar cyclization of nitrile oxide with dipolarophiles generates structurally important heterocycles. As shown by Lee,139 the reaction can be carried out in an aqueous-organic biphasic system in which the nitrile oxide substrates can be generated from oximes or hydrazones in situ. The method provides a convenient one-pot procedure for generating a variety of heterocyclic products. 

Dihydro- and tetrahydrofuroisoxazoline rings were constructed by intramolecular cycloaddition of nitrile oxides or nitrones, generated from oximes . Thus, oxime 30 and sodium hypochlorite afforded furoisoxazolines 31 (equation 14). Similarly, furanyl or thienyl oximes 32 in the presence of NaOCl afforded tricyclic products 33 in 35-90% yields (equation 15). Nitrostyrenes (ArCH=CHN02) and various nucleophiles (for example, allyl mercaptan) also generated hydroximoyl chlorides which underwent similar cycloaddition leading to bicycUc tetrahydrothiophene and tetrahydrofuran derivatives ... 

Cycloadditions with monosubstituted oleflns proceed rapidly and regioselectively to yield the 5-substituted dihydroisoxazoles. Thus, addition of styrene to nitrile oxide 164, formed from oxime 163, results in the formation of the 5-phenyl- 165 and 4-phenyldihy-droisoxazoles 166 in a 99 1 ratio (equation 72) ° °. ... 

Fragmentation of the intermediate or concerted formation of nitriles from the activated oxime (Scheme 9, pathway 3) this is the Beckmann fragmentation. In some circumstances this pathway becomes dominant, particularly when there are quaternary carbons adjacent to the oxime. This transformation has found particular utility in ring-cleavage processes (sometimes called abnormal or second-order Beckmann rearrangements). 

Many different reagents and conditions have been reported to produce nitriles from aldoximes. This conversion is very much expected under the presence of dehydrating agents, proton or Lewis acid and is independent of the oxime geometry. 

Preparation of nitrile acetates from oximes with sodium acetate and acetic anhydride. Pentaacetyl-v-glucononitrile. If only the nitrile is needed, isolation of the oxime can be avoided. One hundred grams of anhydijous n-glucose was dissolved in 50 ml. of warm water, and maintaining the temperature at 60°, a solution of 28 g. of hydro-xylamine in 700 ml. of ethanol was added sufficiently slowly that no precipitation took place. After one hour at 65°, the reaction mixture was concentrated under reduced pressure to a thick sirup. The residue was mixed with absolute ethanol, the ethanol evaporated and the operation repeated in order to eliminate all water. One hundred and twenty grams of anhydrous sodium acetate and 700 ml. of acetic anhydride were added to the sirup, and the mixture was slowly and cautiously warmed in a water bath to 95°. It was advisable to agitate the flask continuously and to watch the... 

Nitrile oxides are normally obtained from oximes in two steps halogenation of the aldoxime (5) to give a hydroximoyl halide (4) and subsequent dehydrohalogenation... 

One-Pot Operations for Nitrile Oxide Formation From Oximes... 

An intramolecular nitrile oxide cycloaddition also served as the key step in the stereoselective assemblage of the skeleton of angular triquinane sesquiterpenes of the isocomene series. Tetracyclic isoxazoline 203 was obtained from oxime 202 [derived from tetrahydroindandione 201] and on treatment with sodium hypochlorite... 

A stereoselective synthesis of testosterone (261) was advanced by Fukumoto and co-workers (331), where ring B was joined to the C/D part by an intramolecular nitrile oxide cycloaddition. The key nitrile oxide dipole was generated in situ from oxime 258, which in turn was derived from the optically active tetrahydroin-danone 257. Tetracyclic isoxazoline (259) was obtained as a single stereoisomer... 

H. Kiliani, as Fischer always emphatically acknowledged, discovered and developed the method of building up the aldose series by the cyanohydrin reaction to give nitriles from the nitrile, the next higher aldonic acid could then be prepared. In 1890, A. Wohl, working in Fischer s Berlin laboratory, elaborated the dehydration of an aldose oxime to the nitrile, from which the next lower aldose could be prepared by loss of hydrocyanic acid. Fischer exploited the possibilities of sugar extension and degradation afforded by the use of these two important methods. 

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