Subject aminolysis

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 ... 

Montaudo and co-workers have used direct pyrolysis mass spectrometry (DPMS) to analyse the high-temperature (>500°C) pyrolysis compounds evolved from several condensation polymers, including poly(bisphenol-A-carbonate) [69], poly(ether sulfone) (PES) and poly(phenylene oxide) (PPO) [72] and poly(phenylene sulfide) (PPS) [73]. Additionally, in order to obtain data on the involatile charred residue formed during the isothermal pyrolysis process, the pyrolysis residue was subjected to aminolysis, and then the aminolyzed residue analysed using fast atom bombardment (FAB) MS. During the DPMS measurements, EI-MS scans were made every 3 s continuously over the mass range 10-1,000 Da with an interscan time of 3 s. 

In 2001, Knaack and co-workers56 reported an application of the INADEQUATE experiment in the course of synthesizing and characterizing a biologically active 2-[l-(4-chlorobenzyl)-lH-indol-3-yl]-2-oxo-N-pyri-din-4-yl acetamide (6). Treatment of l-(4-chlorobenzyl)-lH-indole with oxalyl chloride afforded the corresponding oxoacetyl chloride that was finally subjected to aminolysis with 4-aminopyridine to afford the final product of the reaction scheme, 6. Although the NMR data supported the N-benzyl structure, a 1,1-ADEQUATE spectrum was acquired to provide additional confirmation of the structure of 6. 

Cephalosporins are mostly degraded via intramolecular aminolysis (see above, Fig. 5.8). However, high drug concentrations may also favor degradation via oligomer formation [119]. In the case of loracarbef (5.44, Fig. 5.16), which is not subject to intramolecular aminolysis, the formation of dimeric structures becomes predominant under moderately acidic conditions [120],... 

The methylthio group of the dithiazoline derivative (54) (see Section 4.14.4) is subjected to aminolysis with MejNH <62AG(E)594> or HCONMej <67USP3345374>. 

Three O-substituted benzophenone oximes (29 X = OMe, F, Cl) have been subjected to aminolysis by pyrrolidine and piperidine, in benzene solution.483 Kinetics were third order in amine, and involved two routes one accelerates with a rise in temperature, the other decelerates. Of the many mechanisms proposed for this reaction in non-polar media, the results support Hirst s mechanism of electrophilic catalysis48b in this instance. 

Some research groups have exploited the intrinsic reactivity of the bicycloadducts formed in the pyran-2-one Diels-Alder reactions. An example of this strategy is shown in Scheme 33, where the pyran-2-one decorated with indole functionality 255 was reacted with an assortment of electron-rich and electron-poor dienes <2000T5205>. The richly functionalized bicyclo[2.2.2]adduct 256 was then subjected to mild aminolysis to produce tetrasubstituted hexene 257 as single diastereoisomers. 

Anhydrides react readily with diverse nucleophiles such as amines. For example, the use of acetic anhydride was reported in the 1850s to produce acetamides (40). Symmetric anhydrides 16 can be prepared by dehydrating the corresponding acid under strong acidic conditions or at high temperatures. A more practical approach, however, consists of treating the carboxylic acid with DCC 17 (41). The anhydride is then subjected to aminolysis with the desired amine (see Fig. 5). This method is nsually applicable to peptide synthesis, and, in theory, no additional base is required, as the carboxylate anion is produced in situ. Unfortunately, half of the acid is wasted during the... 

The occasional preliminary purification of products by aqueous washes usually coincides with the use of pyridine or dimethylformamide as solvent. Esters such as succinimido and benzotriazolyl are often prepared in situ, meaning that they are not isolated but subjected to aminolysis immediately after the esterification reaction.P " Slight decomposition can accompany the esterification of Boc amino acids, in particular if dichloromethane is used as solvent and the acidic EDC is used as reagent.P l Publications with a major focus on the synthesis of active esters using DCC are listed in Table 2. A list of Fmoc-Xaa-OR active esters that had been described to 1987 has been compiled.f l... 

These esters (see Tables 10 and 11) are obtained by the usual procedure. The benzotriazolyl esters are rarely isolated because they are too reactive for routine use but are often prepared and subjected to aminolysis immediately.The latter is the case in solid-phase synthesis where DIG is used in preference to DCC because the urea is soluble.P l Benzotriazolyl esters possess the unique feature of existing in two forms in solution, ester 46 being in equilibrium with A -acylated A -oxide 47 (Scheme 9), readily distinguishable by their absorbances in the infrared spectrum at 1827 and 1725 cm respectively.The two forms are stable, the form... 

HDMCTT) (rac-14a) (2 mol equiv) was subjected to aminolysis with 1 mol equiv of optically active amine (or imine). Then the specific rotation of the recovered HDMCTT (14a) was determined. By the sign of its specific rotation, the absolute configuration of the amine (or imine) can be assigned (82TL205). 

Compound 104 was subjected to aminolysis with 1 mol equiv of piperidine, the most useful amine nucleophile in the preliminary test, in CH2CI2 at — 30°C. As the result, a pure major product 105 as yellow needles and a pure minor product 106 as a yellow oil were obtained in a ratio of 88 12 (Scheme 20). 

When racemic aryl glycidyl ethers were subjected to aminolysis in aqueous buffer catalyzed by hepatic microsomal epoxide hydrolase from rat, the corresponding (S)-configurated amino-alcohols were obtained in 51-88% ee 131. On the other hand, when azide was employed as nucleophile for the asymmetric opening of 2-methyl-1,2-epoxyheptane in the presence of an immobilized crude enzyme preparation derived from Rhodococcus sp., which contains an epoxide hydrolase activity, the reaction revealed a complex picture 1321. The (S)-epoxide from the racemate was hydrolyzed (as in the absence of azide), and the less readily accepted (i )-enantiomer was transformed into the corresponding azido-alcohol (ee >60%). Although at present only speculations can be made about the actual mechanism of both the aminolysis and azidolysis reaction, in both cases it was proven that the reaction was catalyzed by a protein and that no reaction was observed in the absence of biocatalyst... 

Similarly, a recent patent combines aminolysis and hydrolysis reactions for achieving polyurethane decomposition.98 Thus, scrap polyurethane is reacted with a mixture of diethanolamine and aqueous sodium hydroxide. The simultaneous attack of these agents on the polymeric chains allows the reaction time to be appreciably shortened. The reaction product, obtained as an emulsion, is subjected to a second treatment with propylene oxide in order to transform the amines and ureas present in the mixture into polyols, giving a final product which is substantially free of any hydrogen-containing nitrogen atoms. The polyols produced have been found to be particularly suitable for the preparation of fresh polyurethane polymer which can be used as an elastomer or flexible foam. 

Introduction.—Few reviews have appeared dealing with more or less general aspects of cyclophosphazene chemistry. The role of cyclophosphazenes as model compounds for reactions of their polymeric analogues has been discussed some fundamental subjects in the area of phosphorus-nitrogen chemistry such as aminolysis, alcoholysis, hydrolysis, and tautomerization phenomena have also been discussed. An extensive review has appeared dealing with reactions of phosphazenes with alkoxides and aryloxides. ... 

Chemical modification of polymer-bound active ester groups is also subject to strong solvent effects. In copolyfAOTcp-styrere), both aminolysis and transesterification with primary alcohols are positively influenced by solvents in the order of dimethylformamide (DMF) > dioxan > diloroform > chlorobenzene > dimethylsulfoxide (DMSO). However, trans-esterification with phenols proceeds in dioxan, but not in DMF. The last-nan d solvent effect is probably related to inactivation of the phenolate ion in DMF, as observed ako for the acylation of polymer-bound phenolic groups by soluble trichlorophenyl esters [64]. 

---