Ammonia primary yields

Hydroxyl Group. The OH group of cyanohydrins is subject to displacement with other electronegative groups. Cyanohydrins react with ammonia to yield amino nitriles. This is a step in the Strecker synthesis of amino acids. A one-step synthesis of a-amino acids involves treatment of cyanohydrins with ammonia and ammonium carbonate under pressure. Thus acetone cyanohydrin, when heated at 160°C with ammonia and ammonium carbonate for 6 h, gives a-aminoisobutyric acid [62-57-7] in 86% yield (7). Primary and secondary amines can also be used to displace the hydroxyl group to obtain A/-substituted and Ai,A/-disubstituted a-amino nitriles. The Strecker synthesis can also be appHed to aromatic ketones. Similarly, hydrazine reacts with two molecules of cyanohydrin to give the disubstituted hydrazine. 

The formamidine is prepared by heating the primary amine in DMF-dimethylac-etal (81-100% yield). Deprotection is effected by heating in EtOH with ZnCl2. LiAlH4 (Et20, reflux), hydrazine (AcOH, MeOH), KOH (MeOH, reflux), dilute ammonia (high yield), and coned. HCl (reflux, 65-90% yield) are also known to cleave the formamidine group. 

When R = CH2OH, the reaction was successful only with primary amines, but not with ammonia which yielded only resinous products. 

Ammonia, primary amines, and secondary amines can all be used in the reductive amination reaction, yielding primary, secondary, and tertiary amines, respectively. 

The two-electron reduction product of terephthalodinitrile reacts with alkyl halides in liquid ammonia to yield 4-alkylbenzonitriles and 2-alkylterephthalodinitriles. The product ratio strongly depends on the alkyl halide and changes in favour of the ipso product, 4-alkylbenzonitrile, on going from tertiary alkyl to primary and from iodide to chloride. This change is the result of increased contribution of the 5n mechanism relative to the ET mechanism. 

The meso-ionic l,3>2-oxathiazol-5-ones (169) show an interesting range of reactions with nucleophiles including ammonia, primary amines, and aqueous alkali. They also react with l,3-dipolarophiles, including dimethyl acetylenedicarboxylate and methyl propiolate, yielding isothiazoles (171) and carbon dioxide. 1,3-Dipolar cycloaddition reactions with alkenes such as styrene, dimethyl maleate, and methyl cinnamate also lead to isothiazoles (171) directly. BicycUc intermediates (cf. 136) were not isolable these cycloaddition reactions with alkenes giving isothiazoles involve an additional dehydrogenation step. 

The guanidine moiety was incorporated by dimethyl (2,2,5,7,8-pentamethylchromane-6-sulfonyl N-alkylated amino) dithiocarbonate[264] (Pmc-dithiocarbonate) 91 in two steps. One methylsulfanyl group was replaced by the primary amino group of Bzl-Norn-OBzl in the presence of excess DIPEA and the isothiourea obtained was reacted with silver nitrate under basic conditions to yield the intermediate sulfonylcarbodiimide which reacts immediately with ammonia to yield the guanidine Bzl-Narg(Pmc)-OBzl 91. 

The reduction of the nitrile proceeds stepwise with formation of a primary aldi.nine which then is hydrogenated to the primary amine (pentyl ami ne). Part of the aldimine condenses with primary amine already formed to produce the unstable aminal. This intermediate looses ammonia to yield a secondary aldimine (dipentylimine) which ultimately leads to secondary amine (dipentyl amine). The reaction of the same primary imine with the secondary amine gives rise to the tertiary amine (tripentylamine), after hydrogenation. 

Under suitable conditions, amide formation can take place between an amine and a carboxylic acid, an acyl halide, or an acid anhydride. Along with ammonia, primary and secondary amines yield amides with carboxylic acids or derivatives. Table 33.2 relates the nitrogen base with the amide class (based on the number of alkyl or aryl groups on the nitrogen of the amide). 

Various p-aminonitriles, which are best prepared by the addition of ammonia, primary amines, or secondary amines to acrylonitrile,101 were successfully hydrogenated with Raney Ni at temperatures of 90-130°C and 6.7-27 MPa H2.102 A typical hydrogenation is shown in eq. 7.50 for P-morpholinopropionitrile. Hydrogenation of the nitrile at 190°C decreased the yield of y-morpholinopropylamine to 45%. The decrease in the yield may be explained by a reversal of the morpholine-acrylonitrile-... 

Mono- and di-alkylacetylenes are prepared from sodium alkydes and primary alkyl halides which lack branching on the second carbon atom. The branched primary halides as well as secondary and tertiary halides undergo dehydrohalogenation to olefins by the basic alkyde. The alkydes are best prepared from the acetylenes and sodium amide in liquid ammonia.The yields of 1-alkynes are frequently 70-90% when alkyl bromides are employed as alkylating agents. Dialkylacetylenes... 

JL olysilazanes have now been prepared by the catalyzed transamination of HSi[N(CH3)2]3 [tris(dimethylamino)silane, Tris], or its derivatives, with ammonia, primary amines, hydrazines, or diamines. Chlorosilane intermediates are not required in this process, because Tris is readily prepared in excellent yield via a new direct reaction of silicon with dimethylamine. 

The Kindler modification of the Willgerodt reaction uses sulfur and dry amines, ammonia, primary amines or secondary amines, which leads to the formation of thioamides (conversion of thioamides to amides cf Section 2.3.1.7). This reaction can also be extended to aldehydes, hydrocarbons and heterocyclic ketones. Due to the usually low to moderate yields this reaction has not found general application. 

The addition of ammonia, primary and secondary amines to the nitrile group proceeds well if electron-attracting groups are present in the a-position to the nitrile function. Thus it is well known that amines add rapidly to trihaloacetonitriles or cyanogen to give amidines (317) and (318) respectively (Scheme 51). Recently it was reported that the addition of aliphatic amines and diamines to aliphatic or aromatic nitriles, respectively, proceeds with good yields if lanthanide triflates are present as catalysts. ... 

Ammonia, 87% yield. In this case an anomeric benzoate was deprotected in the presence of a primary benzoate which shows that benzoates of more acidic hydroxyls are cleaved more rapidly. ... 

Na or Li and ammonia, excellent yields. This is a very good method to remove a benzyl group from an amide and will usually work when hydrogenolysis does not. A dissolving metal reduction can be effected without cleavage of a sulfur-carbon bond. Note also the unusual selectivity in the cleavage illustrated below. This was attributed to steric compression. Primary benzyl amides are not cleaved under these conditions. ... 

The present method eliminates the intermediate preparation of diborane or ammonium salts, and does not require elevated temperatures, as in transamination. The concomitant risk of amino-borane formation is thus avoided. Finally, the present method generally produces high yields or pure product with ammonia, primary, secondary, or tertiary amines, diamines, and with phosphines from readily available starting materials in conventional apparatus.9... 

---