Amines isolation

Aromatic amines can be determined by measuring the difference of their UVV absorption spectra, taken at identical concentrations but different pH of the solution. Also, standard mixtures and samples of the amines isolated from coke processing products were tested LOD 0.1-1 ppm. The procedure is potentially useful for waste waters and industrial effluents, where techniques such as GC and nonaqueous titrations may prove difficult to apply333. A determination of certain metabolites symptomatic of pancreatitis... 

Method A. Monoalkylation CF3CONH2 (11.3 g, 0.1 mol) in MeCN (100 ml) is stirred with the alkylating agent (0.05 mol), powdered K2C03 (13.8 g) and TBA-Br (1.61 g, 5 mmol) at 50°C. When the reaction is complete, as shown by GLC analysis, the cooled mixture is filtered and the residue washed with CH2C12 (30 ml). The combined organic solutions are evaporated and the amine isolated by chromatography from silica. 

SAM-PT and SAM-S strong amines isolated on cation-exchange resin (primary, tertiary, and secondary amines, primarily aliphatic). 

The methodology described above could be successfully applied for the synthesis of compound 240, containing the core structure of the marine metabolites 225, and 226 starting from N-acetyltryptamine (239). Furthermore, the symmetrical bis(indolyl)nitroethane 236a, as a model structure, could be reduced to the corresponding amine, isolated as its N-acetyl derivative 241 (Scheme 53) [174,177],... 

A mixture of the Step 1 product (1.5 mmol) and 4-aminomethylpyridine (4.5 mmol) was heated for 48 hours at 90°C, then cooled and poured into saturated NaHC03 solution. The mixture was extracted with EtOAc and extracts washed with brine, dried, then concentrated. The residual brown oil was purified by chromatography using EtOAc/hexanes, 2 1, and the free amine isolated as clear oil. The free amine was converted to hydrogen chloride salt by dissolving in 5 ml methyl alcohol and treating with 3 equiv. of an HC1 ethereal solution. The mixture was then concentrated and the product isolated as a light yellow solid. 

The product from Step 8 and ethyl chloroformate (1.5 eq) in Et3N and acetone were reacted to yield the mixed anhydride which was treated with sodium azide (1.3 eq) and heated to 80°C in toluene. The resulting isocyanate was stirred 36 hours in an aqueous solution of 20% HCl and the amine isolated. 

The Balz-Schiemann reaction, the classic synthesis of fluoro-aromatic compounds, involves diazotisation of an aromatic amine, isolation of the diazonium fluoroborate or hexafluorophosphate, then thermal decomposition of the dry salt, usually diluted with sand for safety. It is a useful method, with application to a number of heterocyclic systems, for example methyl 3-aminothiophene-2-carboxylate. ... 

To a 1 M solution of the azide in THF is added 1 equivalent of triphenylphosphine, one boiling stone to regulate the evolution of nitrogen gas, and 1.5 equivalents of water. The mixture was stirred for 12 hours, the THF was concentrated in vacuo, and the amine isolated by several different methods (a-c) depending upon the particular product. 

Addition to the C=N of an imine forms the magnesium amide, which is hydrolyzed to an amine. Isolated C=N double bonds of simple imines are relatively unreactive toward organomagnesium compounds, and may instead be depro-tonated at the a-position. Oximes and other N-substituted imines may react better, although an alternative sequence can produce aziridines. Imminium ions, because of their positive charge, are more reactive, and are useful in making tertiary amines. A-Silylimines yield primary amines after hydrolysis. Grignard reagents also add to one C=N of carbodiimides to produce amidines, and to nitrones to produce hydroxylamines. Some varied examples are shown in Scheme 6. 

Work-Up of Reaction Mixture. Soluble iron is generally precipitated with alkali, using caustic soda, soda ash, lime, or magnesia. Where the amine is volatile, it may be isolated by steam distillation or by vacuum distillation from the iron oxide cake after distilling off the water. In the latter case, an efficient scraper agitator must be used to keep the iron oxide from lumping and occluding the product. Where the final amine is soluble in alkaline solution, as is the case with sulfonic acids, carboxylic acids, or sulfonamides, the iron oxide cake is filtered off and the amine isolated from the filtrate. 

Initial concentration of the starting amine. Isolated yield. 

Amines are abundant in nature. Naturally occurring amines isolated from plants are called alkaloids. Below are examples of several alkaloids that have garnered public awareness as a result of their physiological activity ... 

Naturally occurring amines isolated from plants are called alkaloids. 

This reaction, promoted by ethanolic hydrochloric acid at 0-20 , was discovered by Griess and Martins in 1886, and is important in dyestuffs manufacture . Little controversy has arisen over mechanism, which has since 1885 been accepted as fission to a diazo compound or diazonium ion (characterise by coupling with scavenger) and amine (isolable) and recoupling. The marked catalytic effect of arylamines (in acid media) is attributable to reaction (92) , ... 

Kuroda, T. and Kigoshi, H. (2008) Aplaminal a novel cytotoxic aminal isolated from the sea hare Aplysia kurodai. Org. Lett., 10, 489-491. 

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