AMINOLYSIS

Detailed procedures for two driect chemical methods, periodate oxidation and aminolysis, for determination of the phenolic hydroxyl content of lignin or lignin-containing materials are described below. 

The procedure outlined below for the analysis of isolated lignin samples was originally developed by Mansson (1983), and consists of acetylation and aminolysis steps [Eq. (2)] the procedure for lignocellulosic samples is essentially that of Gellerstedt and Lindfors (1984b) and includes a borohydride reduction-step prior to acetylation. 

Polyesters can be attacked by amines, which they can come into contact with when these are used, for example, as additives in other polymers or as components of lubricating oils and adhesives. Attack is usually in the amorphous regions of the polymer [42] but may extend into crystalline domains if exposure is prolonged. Examination of the mechanism of the reaction [43 6] suggests a bimolecular substitution reaction, with protonation of the ester followed by nuleophilic attack by the amine. 

Polyester fibres have been shown to swell and undergo surface cracking on exposure to amine vapours [47]. Studies of PET tyre cords [48] have highlighted the problem of amine additives in the 

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Surfactants have also been of interest for their ability to support reactions in normally inhospitable environments. Reactions such as hydrolysis, aminolysis, solvolysis, and, in inorganic chemistry, of aquation of complex ions, may be retarded, accelerated, or differently sensitive to catalysts relative to the behavior in ordinary solutions (see Refs. 205 and 206 for reviews). The acid-base chemistry in micellar solutions has been investigated by Drummond and co-workers [207]. A useful model has been the pseudophase model [206-209] in which reactants are either in solution or solubilized in micelles and partition between the two as though two distinct phases were involved. In inverse micelles in nonpolar media, water is concentrated in the micellar core and reactions in the micelle may be greatly accelerated [206, 210]. The confining environment of a solubilized reactant may lead to stereochemical consequences as in photodimerization reactions in micelles [211] or vesicles [212] or in the generation of radical pairs [213]. 

The reaction (which is essentially the direct aminolysis of esters with benzylamine) proceeds readily when R is methyl or ethyl. Esters of higher alcohols should preferably be subjected to a preliminary methano-lysis by treatment with sodium methoxide in methanol ... 

Acryhc esters may be saponified, converted to other esters (particularly of higher alcohols by acid catalyzed alcohol interchange), or converted to amides by aminolysis. Transesterification is comphcated by the azeotropic behavior of lower acrylates and alcohols but is useful in preparation of higher alkyl acrylates. 

Condensa.tlon, A variety of condensation reactions involving the hydroxyl or the carboxyl or both groups occur with lactic acid. The important reactions where products can be obtained ia high yields are esterificatioa (both iatramolecular and with another alcohol or acid), dehydration, and aminolysis. 

Reaction of a metal lactate (such as silver lactate) with an alkyl haUde is a classic method of preparation of the ester, but it is too expensive to be of commercial relevance. Lactamide [2043-43-8] is another high yielding condensation product from lactic acid. It can be produced by aminolysis of dilactide or lactate ester such as methyl or ethyl lactate. 

Suitable methods for linking a phosphoms—nitrogen bond to the ayiridine ring are the aminolysis of halogenated phosphoms compounds (2,280—282), the transamination of phosphoramines with excess a iridine (283), the reaction with phosphites (284) and phosphoramidites (285) which have a free OH group, or the reaction of phosphines with a iridines and carbon tetrachloride (286). 

Acidolysis, Aminolysis, and Alcoholysis. When heated, polyamides react with monofunctional acids, amines, or alcohols, especially above the melt temperature, to undergo rapid loss of molecular weight (58,59), eg, as in acidolysis (eq. 3) with acetic acid [64-19-7] or aminolysis (eq. 4) with an ahphatic amine ... 

If adipamide reacts with hexarnethylenediarnine, then nylon-6,6 can be prepared by aminolysis of the adipamide this could also be viewed as reverse ammonolysis. 

Ammonolysis. In a reaction closely related to aminolysis, ammonia [7664 1-7] reacts with polyamides, usually under pressure and at elevated temperatures (62). 

It is generally accepted that transamidation is not a concerted reaction, but occurs through the attack of a free end on the amide group via aminolysis (eg, eq. 4) or acidolysis (eg, eq. 3) (65). Besides those ends always present, new ends are formed by degradation processes, especially hydrolysis (eq. 5), through which the amide groups are in dynamic equiUbrium with the acid and amine ends. 

The step in which the free acid and amine ends recombine (eq. 6) is only accompHshed statistically, since it is unlikely that any two particular ends formed in the acidolysis or aminolysis steps would find each other in the melt. Transamidation is cataly2ed by both acidic and basic ends, but in general acids appear to be much more effective than bases (59,65). 

Mocimycin was prepared from dihydromocimycin (3) by oxidation with selenium dioxide (14,56). 4-Amino-4-dehydroxyefrotomycins were obtained by aminolysis of efrotomycin-4-0-phenylchlorophosphate (57). 

Chemistry. Poly(vinyl acetate) can be converted to poly(vinyl alcohol) by transesterification, hydrolysis, or aminolysis. Industrially, the most important reaction is that of transesterification, where a small amount of acid or base is added in catalytic amounts to promote the ester exchange. 

Synthesis. One of the more common routes for the synthesis of aminoboranes involves the aminolysis of the appropriate boron hahde. Trisaminoboranes are most convenientiy prepared by adding BCI3 to an excess of amine in an inert solvent at low temperatures (42). For example for tris(dimetby1amino)borane [4375-83-1]. ... 

Ammonolysis or aminolysis of an ester can be used to make the respective amide or N-substituted amide. 

There are two basic strategies for enzyme-catalyzed peptide synthesis equiUbrium- and kineticaHy controlled synthesis. The former is the direct reversal of proteolysis and involves the condensation of an amino component with unactivated carboxyl component. The latter proceeds by the aminolysis of an activated peptide ester. 

Ammonolysis and Aminolysis. Esters and ammonia react to form amides and alcohols ... 

If primary or secondary amines are used, A/-substituted amides are formed. This reaction is called aminolysis. Hydra2ines yield the corresponding hydra2ides, which can then be treated with nitrous acid to form the a2ides used in the Curtius rearrangement. Hydroxylamines give hydroxamic acids. 

The aminolysis of esters of pyrimidine occurs normally to yield amides. The reagent is commonly alcoholic ammonia or alcoholic amine, usually at room temperature for 20-24 hours, but occasionally under refiux aqueous amine or even undiluted amine are used sometimes. The process is exemplified in the conversion of methyl pyrimidine-5-carboxylate (193 R = Me) or its 4-isomer by methanolic ammonia at 25 °C into the amide (196) or pyrimidine-4-carboxamide, respectively (60MI21300), and in the butylaminolysis of butyl ttracil-6-carboxylate (butyl orotate) by ethanolic butylamine to give A-butyluracil-5-carboxamide (187) (60JOC1950). Hydrazides are made similarly from esters with ethanolic hydrazine hydrate. 

The ease of displacing a chloro, bromo or iodo substituent in comparable pyrimidines by aminolysis is disappointingly similar. Using 2-halogeno-4,6-dimethyl- and 4-halogeno-... 

Because of their inherent inactivity, only the best leaving groups in the 5-position can undergo aminolysis. Thus, 5-bromo-4-methylpyrimidine (814 R = Br) requires aqueous... 

Probably the best synthesis of 5-methylcytosine is via its 2-thio analogue (964 X = S) (49JBC(177)357) but the following briefly-described route may be preferable 2,4-dimethoxy-5-methylpyrimidine (965) with acetyl chloride gives the 1-acetyl derivative (966) which on aminolysis in aqueous ammonia gives 5-methylcytosine (964 X = O) in good overall yield (68TL2171). 

Ring expansions of suitable /3-lactams can also be achieved on treatment with base rearrangement of the Af-substituted azetidin-2-ones (133) occurs in the presence of LDA to give (134) (72JA9261). Aminolysis of the /3-lactam epoxide (135) and the aldehyde (137) affords (136) and (138) respectively (81JHC1239). 

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