Ketones ammonia with

A class of nitrogen containing compounds that was omitted from the section just dis cussed includes mines and their derivatives Immes are formed by the reaction of aide hydes and ketones with ammonia Immes can be reduced to primary amines by catalytic hydrogenation... 

In Robinson s now well-known suggestions, regarding the processes by which alkaloids may be produced in plants, two main reactions are used j the aldol condensation and the similar condensation of carbinol-amines, resulting from the combination of an aldehyde or ketone with ammonia or an amine, and containing the group. C(OH). N., with substances in which the group, CH. CO. is present. By these reactions it is possible to form the alkaloid skeleton, and the further necessary changes postulated include oxidations or reductions and elimination of water for the formation of an aromatic nucleus or of an ethylene derivative. 

Alkyl-/l -pyrrolines (8, n = 1) and 2-alkyl-/l -piperideines (8, n = 2) are readily formed by the methods used to prepare y- and S-amino ketones (3-6). The reaction of corresponding halogeno ketones with ammonia belongs to the classical reactions of this type. 

Amines can be synthesized in a single step by treatment of an aldehyde or ketone with ammonia or an amine in the presence of a reducing agent, a process called reductive amination. For example, amphetamine, a central nervous system stimulant, is prepared commercially by reductive amination of phenyl-2-propanone with ammonia, using hydrogen gas over a nickel catalyst as the reducing agent. 

Reductive animation (Sections 24.6, 26.3) A method for preparing an amine by reaction of an aldehyde or ketone with ammonia and a reducing agent. 

The synthesis of a-amino acids by reaction of aldehydes or ketones with ammonia and hydrogen cyanide followed by hydrolysis of the resulting a-aminonitrile is called the Strecker synthesis. Enzymatic hydrolysis has been applied to the kinetic resolution of intermediate a-aminonitriles [90,91]. The hydrolysis of (rac)-phenylglycine nitrile... 

In the vast majority of gas-solid reactions, gaseous or evaporated compounds react at the surface of a solid catalyst. These catalytic processes are very frequently used in the manufacture of bulk chemicals. They are much less popular in processing of the large molecules typical of fine chemistry. These molecules are usually thermally sensitive and as such they will at least partially decompose upon evaporation. Only thermally stable compounds can be dealt with in gas-solid catalytic processes. Examples in fine chemicals manufacture are gas-phase catalytic aminations of volatile aldehydes, alcohols, and ketones with ammonia, with hydrogen as... 

Treatment of aldehydes or ketones with ammonia, primary or secondary amines in reducing media is called reductive alkylation (of ammonia or amines) or reductive amination (of aldehydes or ketones). Reducing agents are most frequently hydrogen in the presence of catalysts such as platinum, nickel or Raney nickel [955], complex borohydrides [705, 954, 955], formaldehyde or formic acid [522]. 

Consequently, by choosing proper conditions, especially the ratios of the carbonyl compound to the amino compound, very good yields of the desired amines can be obtained [322, 953]. In catalytic hydrogenations alkylation of amines was also achieved by alcohols under the conditions when they may be dehydrogenated to the carbonyl compounds [803]. The reaction of aldehydes and ketones with ammonia and amines in the presence of hydrogen is carried out on catalysts platinum oxide [957], nickel [803, 958] or Raney nickel [956, 959,960]. Yields range from low (23-35%) to very high (93%). An alternative route is the use of complex borohydrides sodium borohydride [954], lithium cyanoborohydride [955] and sodium cyanoborohydride [103] in aqueous-alcoholic solutions of pH 5-8. 

Pyridine and its derivatives are technically-important fine chemicals. Their isolation from coal tar is decreasing, whereas their manufacture by synthetic methods has increased rapidly. The classical pathways to pyridine have been discussed by Abramovitch (74HC14-1-4). Many of them rely on the reaction of aldehydes or ketones with ammonia in the vapor phase. However, the condensation processes used suffer from unsatisfactory selectivity. Using soluble organocobalt catalysts of the type [YCoL] allows pyridine and a wide range of 2-substituted derivatives to be prepared selectively and in one step from acetylene and the appropriate cyano compound [Eq.(l)]. 

A reaction related to the preparation of 11 is the cycllzation of a-bromo-ketones with ammonia and a second ketone to give imidazolines 14, which are oxidized by sulfur in high yields to 2H-imidazoles 15 (Scheme 6) ... 

In contrast to laboratory scale operations, four-bond formation processes are of considerable importance as industrial routes to pyridine derivatives and have been investigated in Considerable detail. Vapour phase condensation of aldehydes and ketones with ammonia and amines in the presence of a variety of silica/alumina catalysts containing different promoters (e.g. cobalt(II) chloride) can give excellent yields of substituted pyridines (e.g. equation 151), and the nature of the products formed can be largely controlled by change in the stoichiometry of the reactants and variation of experimental conditions (equation 152). 

Several types of cyclocondensation have been used to prepare imidazoles on insoluble supports (Figure 15.7). These include the condensation of 1,2-dicarbonyl compounds with aldehydes and amines, the 1,3-dipolar cycloaddition of iV-sulfonylimines to miinchnones, and the condensation of /V-acylated a-amino ketones with ammonia (Table 15.11). 

A useful synthesis of primary and secondary amines that is related to the reductions just described utilizes the reaction of an aldehyde or a ketone with ammonia or a primary amine in the presence of hydrogen and a metal catalyst ... 

The preliminary condensation of the ketone with ammonia, followed by the catalyzed oxidation of the imine to the oxime ... 

As to its chemical nature, the condensation in question seems to be close to the known synthesis of pyridine derivatives by oxidative condensation of aldehydes and ketones with ammonia discovered by Chichibabin (55MI1). 

An interesting example of heterocyclization involving both the aziridine fragment and the carbonyl group is a reaction of aziridinyl ketones with ammonia and carbonyl compounds, giving rise to 3,5a-dihydro-l//-azireno[l,2-c]imidazoles. This reaction will be considered in more detail in Sects. 1.2 and 1.3. 

The reaction of a ketone with ammonia, followed by catalytic reduction or reduction by sodium cyanoborohydride, produces a 1° amine. 

The preparation of the imine by heating of ketones with ammonia under pressure and subsequent acetylation gives, as a rule, lower yield. 

Treatment of an aldehyde or ketone with ammonia or an amine in the presence of a reducing agent yields an amine... 

CONDENSATION OF o -BROMOPROPIONYL (OR o-BROMOPHENYLACETYL) DERIVATIVES OF AMINOMETHYL KETONES WITH AMMONIA TO ACYLAMINOPYRAZINES... 

The reaction is rather general for ketones with ammonia, primary, and even secondary amines [10] amino acids [12,13] have thus been prepared from a-ketoacids by reductive amination. 

Fig. 13. Reaction of phenyl vinyl ketone with ammonia, [lx 10 M NHa 1 x 10 M NH4CI 2 X 10 m phenyl vinyl ketone successive curves recorded at ten-minute intervals after preparation of the reaction mixture, starting at —0-7 V, S.C.E., 200 mV/absc., full scale sensitivity 9 2 pA.] (Redrawn not accurate to scale.)...

Reductive amination of ketones is accomplished in two steps. The borane complex is used to reduce RR C=N1 C1 which are formed by condensation of the ketones with ammonia in the presence of TiCl,-Ti(OPr )4. 

Formation of pyrazines by high-temperature autoclave reaction of a-halogenomethyl ketones with ammonia. 

Hydroxyphenyl)-l,2,4-triazines 2 and 3 are isolated when ammonium acetate is added to a solution of 2-hydroxybenzohydrazide and a dicarbonyl compound in glacial acetic acid and the resulting mixture is heated at reflux for 2.5 to 5.5 hours.157 This is a special variant of the cyclization of a-acylhydrazono ketones with ammonia or ammonium acetate (see Section 2.2.1.1.1.5.). 

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