Amides aminal ester synthesis

Uses Solvent for liquids, gases, vinyl resins, wire enamels polyacrylic fibers gas carrier catalyst in carboxylation reactions organic synthesis (manufacture of aldehydes, amides, amines, esters, heterocyclics). 

Other Applications. Hydroxylamine-O-sulfonic acid [2950-43-8] h.2is many applications in the area of organic synthesis. The use of this material for organic transformations has been thoroughly reviewed (125,126). The preparation of the acid involves the reaction of hydroxjlamine [5470-11-1] with oleum in the presence of ammonium sulfate [7783-20-2] (127). The acid has found appHcation in the preparation of hydra2ines from amines, aUphatic amines from activated methylene compounds, aromatic amines from activated aromatic compounds, amides from esters, and oximes. It is also an important reagent in reductive deamination and specialty nitrile production. 

Another alternative for preparing a primary amine from an alkyl halide is the Gabriel amine synthesis, which uses a phthalimide alkylation. An imide (—CONHCO—) is similar to a /3-keto ester in that the acidic N-H hydrogen is flanked by two carbonyl groups. Thus, imides are deprotonated by such bases as KOH, and the resultant anions are readily alkylated in a reaction similar to the acetoacetic ester synthesis (Section 22.7). Basic hydrolysis of the N-alkylated imide then yields a primary amine product. The imide hydrolysis step is analogous to the hydrolysis of an amide (Section 21.7). 

During the coverage period of this chapter, reviews have appeared on the following topics reactions of electrophiles with polyfluorinated alkenes, the mechanisms of intramolecular hydroacylation and hydrosilylation, Prins reaction (reviewed and redefined), synthesis of esters of /3-amino acids by Michael addition of amines and metal amides to esters of a,/3-unsaturated carboxylic acids," the 1,4-addition of benzotriazole-stabilized carbanions to Michael acceptors, control of asymmetry in Michael additions via the use of nucleophiles bearing chiral centres, a-unsaturated systems with the chirality at the y-position, and the presence of chiral ligands or other chiral mediators, syntheses of carbo- and hetero-cyclic compounds via Michael addition of enolates and activated phenols, respectively, to o ,jS-unsaturated nitriles, and transition metal catalysis of the Michael addition of 1,3-dicarbonyl compounds. ... 

Amides contain an acid portion and an amine portion. However, unlike the formation of an ester, the reaction of a carboxylic acid with an cimine is not an efficient method for preparing an amide, because, as you see in this section, the simple reaction of an acid (carboxylic acid) with a base (amine) causes interference. Fortunately, methods similar to many of the other ester synthesis methods are useful in the synthesis of amides. 

Other Applications. Hydroxylainine-O-sulfonic acid has many applications in the area of organic synthesis. The acid has found application in the preparation of hydrazines from amines, aliphatic amines from activated methylene compounds, aromatic amines from activated aromatic compounds, amides from esters, and oximes. 

A number of selective transformations (Fig. 10) have been described which include the selective allylation on alcohols in the presence of amides [47], the Lewis acid catalyzed cleavage of benzyl alcohol esters with secondary amines to afford tertiary amides [48], the synthesis of ketones from Weinreb-type amides [49], and the synthesis of tertiary amines by a Michael addition/alkylation/Hoffman elimination sequence [50],... 

Classical reactions involving nucleophiles such as saponification ("OH as the nucleophile), aminolysis (with amines also ammonia in ammonolysis reactions), transesterification (alkoxides, "OR) and others (hydrazinolysis, hydroxamic acid synthesis, etc.) have been adapted to solid phane and used to obtain, for instance, carboxylic acids, amides and esters. Internal or intramolecular nucleophilic attack has been employed to obtain cyclic products such as lactones, lactams (including cyclic peptides) and a great variety of heterocycles (hydantoins, diketopiperazines, benzodiazepinones, etc.). 

Secondary amides react selectively to yield esters and sulfilimines, which can then be converted into the corresponding amines. For example, amide 17 reacts with sulfurane 1 to furnish ester 19 and sulfilimine 18 which yields amine 21 upon reaction with either hydrochloric acid followed by base or hydrogen gas and catalytic palladium on carbon. Thus, this reaction can function both as an ester synthesis and an amine deprotection. Bulky secondary amides do not immediately undergo cleavage and instead yield imidates that, upon treatment with aqueous acid, furnish amines and esters. For example, combination of Martin s sulfurane (1) with amide 22 provides imidate 23 that can be easily converted into amine 25 and ester 24. Primary amides provide Af-acylsulfilimines, while tertiary amides are completely unreactive.7... 

Fractional distillation after synthesis of volatile amides or esters met with little success, due to low differences in boiling points (4-5 K or < 1 K) and laborious transformations. [7] An early distillation approach using different volatilities of diastereomeric salts of various amines with tartaric acid or its diben-zoyl- (also di-p-toluoyl-) derivatives yielded optical purities of the distillates from 5 to 47 % with a better performance in the case of methamphetamine (56.5-66.5 %). [8] However, probably due to the ban or restrictions with this drug (and most further drugs that might be misused) for use in scientific research by many countries, that publication did not find its due recognition. A further rea-... 

---