Cyanopyridines ammonia

Cyanopyridine-Ru(NH 3)5" 4-Cyanopyridine Ammonia Isopropylamine Benzylamine 4-f-Butylpyridine 4-Phenylpyridine A - -pentylpyrazinium (34)... 

Hydrogenation of 3-cyanopyridine (25) in the presence of ammonia gives 3-pico1ylamine [3731 -52-0] (29) however, hydrogenation in the presence of hydrogen chloride affords the corresponding 3-carbinol (30) (31). 

FIGURE 2.30. Redox catalysis induction of Srn1 reactions. Cyclic voltammetry in liquid ammonia + 0.1 M KC1 at —40°C of (a) redox catalyis of the reductive cleavage of 2-chlorobenzonitrile, RX, by 4-cyanopyridine, P. The dotted reversible cyclic voltammogram corresponds to P in the absence of RX. The solid line shows the catalytic increase of the current, (b) Transformation of the voltammogram upon addition of the nucleophile PhS. Adapted from Figure 1 in reference 23, with permisison from the American Chemical Society. 

The equilibrium between radical-anion and dimer for pyridine and quinoline has been examined in a number of aprotic solvents. Radical-anions of pyridine dimer-ise rapidly in liquid ammonia in tire presence of alkali metal ions [15] In hex-amethylphosphoramide with alkali metal counter ions, the monomer is detectable in an equlibrium concentration [16], The monomeric species can be stabilised by substituents and 2- or 4-cyanopyridines give radical-anions which persist in liquid ammonia while 3-cyanopyridine radical-anion dimerises with a rate constant of 2 x 10 [17], Quinoline radical-anion is stable in hexamelhylphosphoramide [16] but in liquid ammonia it dimerises irreversibly [18]. 

A number of routes are available for the synthesis of 2,2 -bipyridines where one of the pyridine rings is built up from simpler entities. For example, condensation of 2-(aminomethyl)pyridine (31) with acetaldehyde or acetylene over a silicon-alumina catalyst at 450°C gives 2,2 -bipyridine, ° whereas 2-cyanopyridine reacts with acetylene at 120°C in the presence of a cobalt catalyst to afford 2,2 -bipyridine in 95% yield.2-Acetylpyridine with acrolein and ammonia gives 2,2 -bipyridine in the presence of dehydrating and dehydrogenating catalysts, and related condensations afford substituted 2,2 -bipyridines. ° In a similar vein, condensation of benzaldehyde with 2 mol of 2-acetylpyridine in the presence of ammonia at 250°C affords 2,6-di(2-pyridyl)-4-phenylpyridine, ° and related syntheses of substituted 2,2 6, 2"-terpyridines have been described. Likewise, formaldehyde with two moles of ethyl picolinoylacetate and ammonia, followed by oxidation of the product and hydrolysis and decarboxylation, affords a good... 

Like 2,2 - and 2,3 -bipyridines, 2,4 -bipyridine is formed by a number of reactions where one of the pyridine rings is built up from simpler components. Thus 4-(aminomethyl)pyridine with acetylene or acetaldehyde at 450"C affords 2,4 -bipyridine and 4-cyanopyridine reacts with acetylene at 120 C under pressure in the presence of a cobalt catalyst to give 2,4 -bipyridine in over 90% yield. 4-Acetylpyridine with acrolein and ammonia in the presence of dehydrating and dehydrogenating catalysts also gives 2,4 -bipyridine. A number of minor routes to 2,4 -bipyridine are worthy of... 

Temperature-dependent data have been selected for 25°C as far as available in these sources, unless the solvent is not liquid at this temperature. Such solvents, from among the List, are /-butanol (No. 310), c-hexanol (No. 360), -dodecanol (No. 390), 1,4-butanediol (No. 540), phenol (No. 590), 2-methylphenol (No. 600), 4-methyl- phenol (No. 620), 2-methoxyphenol (No. 630), 3-chlorophenol (No. 650), phenyl-acetone (No. 1060), / -methylacetophenone (No. 1070), benzophenone (No. 1090), ethylene carbonate (No. 1350), diethanolamine (No. 1940), 2-cyanopyridine (No. 2040), N-methylacetamide (No. 2240), di- -butylsulfoxide (No. 2410), sulfolane (No. 2420) hexamethyl thiophosphoramide (No. 2520), hydrogen fluoride (No. 2540), ammonia (No. 2560), and sulfur dioxide (No. 2580). Several of these have melting points sufficiently close to 25°C, so that they are readily used in the slightly supercooled state, and values for this... 

The pyridopyrimidines (288) have been prepared by reaction of A,A -dibenzylidenephenyl-methanediamines with 2,6-diaryl-4-piperidones <83S564>. The C-nucleoside analogue (289) was obtained by the cyclization of a- and /l-5-ribosyl-4-amino-3-cyanopyridine with HC(0Et)3-Ac20 followed by treatment with saturated methanolic ammonia, whereas compound (290) was prepared by conversion to the amide before cyclization <92M1716-01). 

Alkaline dimerization of o-aminonitriles is exemplified by the compound (82) formed by heating 2-amino-3-cyanopyridine in aqueous ammonia.33... 

The more reactive 2-chloro-3-fluoropyridine (89) is aminated readily by piperazine in boiling -butanol to give —60% of 90 (83JMC16%). The presence of a polar cyano group allows the 2-chloro-3-cyanopyridine (72) to be aminated already at I00°C by methylamine to 2-methylamino-3-cyanopyridine (91) in 63% yield (85SC10I3). An additional 6-chloro group, as in 92, leads, upon amination with ammonia to a mixture of the corresponding amino compounds 93 and 94. With the weakly basic aniline in the... 

The ammoxidation step (Scheme 15.7) utilizes a catalyst that selectively converts picoline in the presence of oxygen and ammonia into 3-cyanopyridine. Even at... 

Ethyl nicotinate upon treatment with concentrated ammonia solution yields nicotinamide, which gives p-cyanopyridine upon heating with phosphoric oxide ... 

Radical anions and dianions were also observed in the electroreduction of 2- and 4-cyanopyridines in liquid ammonia at a Pt cathode. Under similar conditions the 3-cyano derivative afforded a radical anion which underwent a fast dimerization. 

Cyanopyridines are prepared by passage of nicotinic or isonicotinic acid, their ammonium salts, or amides over a dehydration catalyst at 350° in the presence of ammonia. Boron phosphate and aluminum phosphate are mentioned specifically as catalysts. ... 

The retro-Hofmann consideration is based on the availability of pyridine-3-carboxamide on a large scale. Actually, this compound, known as nicotinamide or vitamin B3, is produced in multi-ton quantities from 3-methylpyridine [20, 21]. For this building block, the catalytic industrial process is based on the one-pot cyclization of acrolein, ammonia and propanal in the presence of oxides of Sb(II), Ti(IV) or V(V) as catalysts. 3-Methylpyridine is submitted to amoxidation, the combined action of oxygen and ammonia to obtain 3-cyanopyridine (Scheme 8.9) [22]. 

In contrast to the cyanopyridines, 4-cyanopyridine methiodide reacts readily with ammonia giving 4-aminopyridine methiodide . 

S]s lcb-type deprotonation of coordinated ammonia, followed by an intramolecular reaction generating coordinated bidentate amidophosphate. This can then react further with either Ir—N or Ir—O bond cleavage (Scheme 3). A series of copper(II) complexes of general formula [Cu(15)Cl2] has been shown to be effective in the hydrolysis of fluorophosphates. The complexes themselves are prepared in a metal-directed addition of ROH to 2-cyanopyridine. A very mild hydrolysis of coordinated trimethylphosphite to dimethylphosphonate is seen in the conversion of [ P(CH2CH2PPh2)3 Pt P(OMe)3 ] + to [ P(CH2CH2PPh2)3 Pt P(=0)(0Me)2 ]+ upon... 

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