For conversion of amines

Carboxylic acids can also be activated by the formation of mixed anhydrides with various phosphoric acid derivatives. Diphenyl phosphoryl azide, for example, is an effective reagent for conversion of amines to amides.140 The proposed mechanism involves formation of the acyl azide as a reactive intermediate. 

The recently prepared benzotriazole-l-carboxamidinium tosylate represents a convenient reagent for conversion of amines to guanidines in moderate to good yields. The presence of the benzotriazole moiety causes the compound to be more reactive than pyrazole-1 -carboxamidinium hydrochloride [ni... 

Both dimethyl carbonate [616-38-6] and diphenyl carbonate [102-09-0] have been used, in place of carbon monoxide, as reagents for the conversion of amines into isocyanates via this route (28,29). Alternatively, aniline [62-53-3] toluene diamines (I JJA), and methylene dianilines (MDA) have also been used as starting materials in the carbonylations to provide a wide variety of isocyanate monomers. 

For some years, this type of vehicle was used in anionic electro deposition primers. However for automobiles cationic electro deposition primers are now preferred. The vehicles for cationic primers are proprietary but probably consist of the reaction product of epoxy resins and polyfunctional amines solubilized by the conversion of amine groups into salts using an acid such as lactic acid (2-hydroxypropanoic acid) [50-21-5] Alcohol-blocked... 

The preparation of an alkene 3 from an amine 1 by application of a /3-elimination reaction is an important method in organic chemistry. A common procedure is the Hofmann elimination where the amine is first converted into a quaternary ammonium salt by exhaustive methylation. Another route for the conversion of amines to alkenes is offered by the Cope elimination. 

If one limits the consideration to only that limited number of reactions which clearly belong to the category of nucleophilic aromatic substitutions presently under discussion, only a few experimental observations are pertinent. Bunnett and Bernasconi30 and Hart and Bourns40 have studied the deuterium solvent isotope effect and its dependence on hydroxide ion concentration for the reaction of 2,4-dinitrophenyl phenyl ether with piperidine in dioxan-water. In both studies it was found that the solvent isotope effect decreased with increasing concentration of hydroxide ion, and Hart and Bourns were able to estimate that fc 1/ for conversion of intermediate to product was approximately 1.8. Also, Pietra and Vitali41 have reported that in the reaction of piperidine with cyclohexyl 2,4-dinitrophenyl ether in benzene, the reaction becomes 1.5 times slower on substitution of the N-deuteriated amine at the highest amine concentration studied. 

The addition of a secondaiy amine (shown above) produces a tertiary amine, while addition of a primary amine gives a secondary amine. The overall orientation follows Markovnikov s rule. For conversion of 35 to other products, see 15-52. 

Another reaction that can be used for conversion of carboxylic acids to the corresponding amines with loss of carbon dioxide is the Hofmann rearrangement. The classic reagent is hypobromite ion, which reacts to form an A-bromoamide intermediate. Like the Curtius reaction, this rearrangement is believed to be a concerted process and proceeds through an isocyanate intermediate. 

For conversion of amide to other acid derivatives, a novel synthesis of urea glycosides in aqueous media has been reported via the reaction of Steyermark s glucosyl carbamate with amines in good yields (Eq. 9.17).38 This method was successfully applied to develop a new route to the synthesis of urea-tethered neo-glycoconjugates and pseudooligosaccharides. 

TMPD (k = 5.2 x 108 M 1s 1), p-diaminobenzene (k = 5 x 107 M 1s 1) and diphenylamine (k = lx 107 M 1 s 1) can all be readily converted into the corresponding radical cation by oxidation with pulse radiolysis generated SC>3 . With higher redox potential amines such as aniline and A. /V-dimethylandinc the oxidation to the radical cation fails32. Rate constants have also been measured for conversion of the same amines... 

The most popular reducing agent for conversion of aromatic nitro compounds to amines is iron [166]. It is cheap and gives good to excellent yields [165, 582]. The reductions are usually carried out in aqueous or aqueous alcoholic media and require only catalytic amounts of acids (acetic, hydrochloric) or salts such as sodium chloride, ferrous sulfate or, better still, ferric chloride [165]. Thus the reductions are run essentially in neutral media. The rates of the reductions and sometimes even the yields can be increased by using iron in the form of small particles [165]. Iron is also suitable for reduction of complex nitro derivatives since it does not attack many functional groups [555]. 

Substituted hydroxylamines 1-5 (R = R = H) and their A-mono- or A,A-disub-stituted derivatives 1-5 have been used extensively for electrophilic amination of both carbanions and enolates since the first report in 1938 on the use of 0-methylhydroxylamine 1 (R = Me) for conversion of Grignard reagents to primary amines. Oximes 7 (Z = H) have found limited applicability as amination reagents for carbon nucleophiles and then-use was first reported in 1907. Ketone 0-sulfonyloximes 7 (Z = SO2R) have recently been developed. 

For conversion of functionalized diorganozincs into tertiary amines, aromatic compounds which contain a directed metallation group, such as Af,Af-dialkylbenzamides, methoxymethyl phenyl ether, phenyl oxazolines and phenyl Af,Af-dialkylcarbamates, were ortho-lithiated, transmetallated and then aminated with 2a in good yields, but with a slower reaction rate (Scheme 19). 

Alvernhe and Laurent first developed a procedure for conversion of Grignard reagents to primary amines using acetone oxime 6c and butanone oxime 6d (Scheme 55) 22 23 However, the yields were low. They expanded their study to investigate how well organo-lithiums perform in their reaction with 6c or 6d 23. Phenyllithium gave a 1 4 mixture of aniline and the addition product of phenyllithium to the imine (Scheme 53, path e product) in the reaction with 6c while aziridine was obtained in the reaction with 6d (Scheme 56). 

Yamazaki Higashi Iguchi Tetrahedron Lett. 1974, 1191. For other methods for the conversion of amines and CO- to ureas, see Ogura Takeda Tokue Kobayashi Synthesis 1978, 394 Fournier Bruneau Dixneuf Ldcolier J. Org. Chem. 1991, 56, 4456. 

Alkyl phenyl setenides selenol esters. N-PhcnylscIcnophthalimidc is superior to aryl selenocyanates for conversion of alcohols to alkyl phenyl selenides (6, 252-253) and of carboxylic acids to selenol esters (7, 396-397). When conducted in the presence of an amine the latter reaction provides amides in high yield (equation l). ... 

Reduction reactions, which usually convert imine to secondary amine functions, are also metalion specific and usually most successful for the Ni" complexes. Reductions can be by electrochemical means or by chemical reductants such as NaBH4, NiAl/OH, H2/Pt or H2/Ni. H3P02 is specific for conversion of an a-diimine group to a monoimine. Examples of imine complexes which have been reduced to form cyclic amine complexes include (1), (3), (4), (9), (16) and (20). 

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