Pyridyl ammonia

A novel synthesis of nornicotyrine has been described by Lions and Ritchie, who condensed ethyl nicotinylacetate hydrochloride with a -dichlorodiethyl ether in presence of ammonia at — 10° to — 13° and then at room temperature, producing mainly ethyl 2-(3 -pyridyl)furan-3-carboxylate, but also some ethyl 2-(3 -pyridyl)pyrrole-3-carboxylate,... 

From a mechanistic standpoint, ammonia serves two functions 1) it behaves as a base to catalyze an aldol reaction between 2 equivalents of 31 to generate the corresponding enal 33, and 2) it is the source of nitrogen for the resultant pyridyl ring. This occurs through formation of enamine 34 with a third equivalent of 31. The Michael addition of 34 to 33 followed by cyclization gives rise to 32. 

According to U.S. Patent 2,676,964 to 1.0 mol of potassium amide in 3 liters of liquid ammonia, is added 1.0 mol of 2-benzylpyridine. After 15 minutes, 1.1 mols of 3reaction product decomposed with water and ether extracted. The ether layer is dried over Sodium sulfate and after evaporation the residue is distilled, giving the 3-phenyl-3-(2-pyridyl)-N,N-dimethylpropylamine, BP 139°-142°C/1-2 mm. The maleate is produced by reaction with maleic acid. 

The mixture is poured onto excess ice, acidified with concentrated hydrochloric acid, the ether layer sepatated and extracted with water (1 x 200 cc). The combined aqueous extracts are washed with ether (1 x 200 cc) basified with 0.880 ammonia and extracted with chloroform (3 x 350 cc) the extract is washed with water (2 x 100 cc), dried over sodium sulfate, evaporated, and the residue extracted with boiling light petroleum (BP 60° to 80°C 10 volumes), filtered hot and evaporated to dryness. The residue is recrystallized from alcohol to give a cream solid (119 g, 80%), Pi/IP 117° to 118°C. Recrystallization gives 1-(4-methylphenyl)-1-(2-pyridyl)-3-pyrrolidonopropan-1-ol, MP 119° to 120°C. 

First, 4-chloropyrimidine 86 was treated with phenylacetylene to give alkynylpyrimidine 87 [62], The fact that the Sonogashira reaction proceeded readily at room temperature may be ascribed to the electron-withdrawing effect of the neighboring ethoxycarbonyl group on 86. When heated with ammonia in EtOH, alkynylpyrimidine ester 87 cyclized efficiently to produce pyridyl lactam 88. 

The water-soluble Fe porphyrin, 3Na+ [Fe(III)(TPPS)] -12H20 [H2TPPS4- = tetra-anionic form of meso-tetrakis(7r-sulfonatophenyl)porphine], has recently been shown to be an effective catalyst for the electroreduction of nitrite to ammonia [419]. The Fe meso-tetrakis(A -methyl-4-pyridyl) porphyrin and/or the Fe meso-tetrakis (jr -sulfophenyl) porphyrin complex shows a catalytic activity for the reduction of dioxygen in aqueous solutions, leading to hydrogen peroxide [420]. 

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... 

Pyridyl)tetrahydropyran (32), when treated with ammonia over alumina at about 400°C, also gives 2,2 -bipyridine. In another related synthesis, the pyrylium salt 4,6-diphenyl-2-(2-pyridinio)pyrylium bis(tetra-fluoroborate) was converted to 4,6-diphenyl-2,2 -bipyridine by anhydrous ammonia in ethanol. ... 

As in the synthesis of other bipyridines, several routes to 4,4 -bipyridine have been devised where one of the pyridine rings is built up from simpler components. For example, a dimer of acrolein reacts with ammonia and methanol in the presence of boron phosphate catalyst at 350°C to give a mixture of products including 4,4 -bipyridine (3.4% yield), and in a reaction akin to ones referred to with other bipyridines, 4-vinylpyridine reacts with substituted oxazoles in the presence of acid to give substituted 4,4 -bipyridines. ° ° Condensation of isonicotinaldehyde with acetaldehyde and ammonia at high temperatures in the presence of a catalyst also affords some 4,4 -bipyridine, and related processes give similar results,whereas pyran derivatives can be converted to 4,4 -bipyridine (56% conversion), for example, by reaction with ammonia and air at 350°C with a nickel-alumina catalyst. Likewise, 2,6-diphenyl-4-(4-pyridyl)pyrylium salts afford 2,6-... 

To complete the section on the synthesis of 4,4 -bipyridines, we summarize the methods reported for the preparation of some substituted 4,4 -bi-pyridines and 4,4 -bipyridinones. These methods are closely analogous to syntheses already discussed for some of the isomeric bipyridines. Thus the Hantzsch reaction using pyridine-4-aldehyde, ethyl acetoacetate, and ammonia gives 3,5-di(ethoxycarbonyl)-1,4-dihydro-2,6-dimethyl-4,4 -bipyridine, which after oxidation, followed by hydrolysis and decarboxylation, afforded 2,6-dimethyl-4,4 -bipyridine. Several related condensations have been reported. Similarly, pyridine-4-aldehyde and excess acetophenone gave l,5-diphenyl-3-(4-pyridyl)pentane-l,5-dione, which with ammonium acetate afforded 2,6-diphenyl-4,4 -bipyridine. Alternatively, 1-phenyl-3-(4-pyridyl)prop-2-enone, A-phenacylpyridinium bromide, and ammonium acetate gave the same diphenyl-4,4 -bipyridine, and extensions of this synthesis have been discribed. Condensation of pyridine-4-aldehyde with malononitrile in the presence of an alcohol and alkaline catalyst produced compounds such as whereas condensations of... 

R = Ph) is the most widely investigated of these compounds and serves as a suitable reference compound. Kalb and Bayer3 reported the methanol, ammonia, aniline, and sodium bisulfite adducts of this compound. The reactivity of the indolone increases when the electron density at the 2-position is reduced. In these cases (158 R = 4-nitrophenyl, 2-pyridyl, C02alkyl),49,61,62,91 the indolone adducts (175 Nu = OH, OEt) are stable and isolable the free indolones do not exist. The 2-alkylindolones (158 R = alkyl), in which the conjugation of the azomethine group is less extensive, are also very reactive. They too are only isolated as adducts (175 R = alkyl Nu = OH) with the exception of 158 (R = 1-Bu, Section IV,A,2). 

To a mixture of 100 ml of liquid ammonia and about 80 mg of black iron oxide was added 0.78 g (0.02 atom) of potassium. When all of the potassium had reacted, 3.3 g of N,N-dimethyl-N -(2-pyridyl)ethylenediamine was added. After the addition of 75 ml of dry toluene the ammonia was removed on the steam bath. To the cooled and stirred mixture was added 4.26 g of p-chlorobenzyl chloride, and the reaction mixture was stirred on the steam bath for 11 hours. It was then filtered and concentrated to an oil. This concentrate was taken up in ether, and the ethereal solution was washed with water, dried over sodium sulfate, and concentrated. Distillation gave 2.96 g of yellow liquid. Treatment of this distillate with an equivalent quantity of hydrogen chloride in absolute alcohol and precipitation by the addition of anhydrous ether gave 2.33 g of the N,N-dimethyl-N -(4-chlorobenzyl)-N -(2-pyridyl)ethylenediamine hydrochloride. 

The acidic solution, containing the 2-(2-dimethylaminoethyl)-l-[l-(2-pyridyl)-ethyl]-indan-l-ol is heated on the steam bath for thirty minutes to effect dehydration to the desired indene derivative. The solution is cooled, made strongly basic with an aqueous solution of ammonia and then extracted with ether. The ether phase is dried over sodium sulfate, filtered, evaporated and the residue distilled. 

A solution of 4-[2-(5-ethyl-2-pyridyl)ethoxy]nitrobenzene (60.0 g) in methanol (500 ml) was hydrogenated at room temperature under one atmospheric pressure in the presence of 10% Pd-C (50% wet, 6.0 g). The catalyst was removed by filtration and the filtrate was concentrated under reduced pressure. The residual oil was dissolved in acetone (500 ml)-methanol (200 ml). To the solution was added a 47% HBr aqueous solution (152 g). The mixture was cooled, to which was added dropwise a solution of NaN02 (17.3 g) in water (30 ml) at a temperature not higher than 5°C. The whole mixture was stirred at 5°C for 20 min, then methyl acrylate (112 g) was added thereto and the temperature was raised to 38°C. Cuprous oxide (2.0 g) was added to the mixture in small portions with vigorous stirring. The reaction mixture was stirred until nitrogen gas evolution ceased, and was concentrated under reduced pressure. The concentrate was made alkaline with concentrated aqueous ammonia, and extracted with ethyl acetate. The ethyl acetate layer was washed with water and dried (MgS04) The solvent was evaporated off to leave methyl 2-bromo-3- 4-[2-(5-ethyl-2-pyridyl)ethoxy]phenyl propionate as a crude oil (74.09 g, 85.7%). 

Chlorination of the derivatives (500) with phosphorus oxychloride followed by reaction with ammonia, gives the 2-amino-3-bromopyridines (501). Cyclization of (501 R = 4-pyridyl) was accomplished by heating with ethyl potassium xanthate in l-methyl-2-pyrrolidinone at 160-165 °C to give the thiazolo[4,5-6]pyridine (502 R = 4-pyridyl) in near quantitative yield (Scheme 61) (94JMC248). 

The pyrrolyl-pyridine and -quinoline precursors 1225 have been prepared via an electroinduced SrnI reaction in liquid ammonia by reacting pyrrolyl anions 1223 and the corresponding aryl halides 1224 (pyridyl and quinolyl chlorides) (Scheme 235) <2004S0517>. 

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