Ammonium salts, amides prepared

Three types of lubricants which possess both the perfluoroalkyl group and hydrocarbon long chain, that is an ester, amide, and carboxylic acid amine salt, were synthesized by the following Scheme 1 in Fig.4. The ester and the amide were prep>ared by the addition of carboxylic add chloride to the hexane solution of the corresponding alcohol and amine in the presence of a base agent. The perfluorocarboxylic add and the carboxyhc add ammonium salts are prepared by warming the mixture of the perfluorocarboxylic add and the amine to 80°C imtil the complete dissolution was obtained (Scheme 2).(Kondo et al., 1989,1994)... 

Aldonamides are readily prepared by reaction of lactones with liquid ammonia (86,99,100), with ammonium hydroxide (101,102), or by bubbling ammonia gas into alcoholic solutions of the sugar lactones (103-104). Aldonamides of the tetronic adds are stable in aqueous solution (105), but penton- or hexon-amides are hydrolyzed, as shown by the change of the optical rotation of the amide solutions (106). The hydrolysis is catalyzed by acids and bases, and the product was the ammonium salt of the aldonic acid. 

Amides are prepared, quite generally, from the acids by subjecting the ammonium salts to dry distillation, or still better, by beating them for a long time at a high temperature. 

Since, as has been described above, amides can be obtained by removal of water from the ammonium salts of acids, nitriles can be prepared directly from ammonium salts in one operation by heating them with a powerful dehydrating agent, e.g. ammonium acetate with P205 ... 

Nucleophilic attack only occurs upon heating the ammonium salt, resulting in overall dehydration of the salt. Consequently, it is usual to prepare amides by using a more favourable substrate than the carboxylic acid, one that is more reactive towards nucleophiles by virtue of possessing a better leaving group, and where salt formation does not hinder the reaction. 

Solid cyclic carboxylic anhydrides react with gaseous ammonia to give amide ammonium salts with quantitative yield. This has been observed with the labile Diels-Alder adduct 259 [25] (Scheme 38). Aliphatic amine vapors are equally able to open anhydride rings to form the amide salts from where the free amide acids can be obtained in 100% yield. The reaction of 261 with ethylamine to give 262 is an example of a large-scale preparative application [11-12]. Conversely, solid pyromellitic bis-anhydride (263) and methylamine vapor react exother-mally (rise to 95 °C) and quantitatively to yield the tetraamide 264. Interest-... 

Amides can be prepared from ammonia and other acid derivatives. They can also be prepared by heating ammonium salts. They are named by replacing the -ic or -oic acid ending with amide. 

Write equations for the preparation of a given amide from an acyl halide, acid anhydride, or ammonium salt. 

Solvent-free uncatalyzed amidations of acids occurred readily under microwave conditions when conducted with a slight excess of either amine or acid (1.5 equiv). The pathways involved thermolysis of the previously formed ammonium salts (acid-base equilibrium) and proceeded by nucleophilic attack of the amine on the carbonyl moiety of the acid, with removal of water. This procedure was extended to the preparation of functionalized tartramides directly from amines and tartaric acid under solvent-free conditions and microwave activation (Scheme 10). By conventional heating, yields were lower even after 16 h. 

A -Alkyl-A -(/3-keto)amides 1216 have been prepared using a traceless linker strategy starting from resin-bound benzylamines 1215. The ketoamides 1217 released from the resin react with an ammonium salt to afford 1,2,4-trisubstituted imidazoles 1218 in good yields and high purities (Scheme 297) <20000L323>. 

This melts at 226° C., forms an ammonium salt, decomposing at 200° C., and a benzoyl derivative, M.pt. 284° C. In the preparation of the glycine-amide, longer heating, or recrystallisation from an excess of alkali, causes it to change to the quinoxaline. If the latter in sodium hydroxide solution is allowed to stand for several days at 30° C. with an excess of ethylene oxide, the mixture being occasionally shaken, S-hydroiryethyl-amino-6-arsino-l i-dihydroquinoxaline is fomred. 

Besides water for hydrothermal reactions, liquid ammonia (bp, 78°C Tc, 132°C Pc, 113 atm) is also used for the solvothermal synthesis of nitrides. Metastable or otherwise unobtainable nitride materials were reported to be formed by this rnethod. " Ammonium and amide (NH2) ions are the strongest acid and base, respectively, for the liquid ammonia system, and therefore ammonium salt acts as the acid mineralizer, while amide ion can be prepared by addition of alkali metals to the solvent. Since ammonia has a low boiling point, the reaction pressure is usually quite high. 

From Ammonium Salts.—Still another method for the preparation of acid amides is to simply heat the ammonium salt of the acid. The action taking place has been shown to result in the loss of one molecule of water. 

The products are the acid and ammonia which react forming the ammonium salt of the acid. This is, of course, simply the reverse of the third method given for preparing the amides (p. 145). 

In the aromatic series the direct conversion of acid amides into acid nitriles does not take place readily but the acid itself is made from the acid amide by the reverse process as indicated above, viz., by hydration to the ammonium salt of the acid, which then yields the acid. A related method, however, is used for preparing acids from anilides of formic acid. Aniline being an ammonia compound yields acid-amidelike products with aliphatic acids, e.g. acet anilide, CH3—CO—NH— CeHs (p. 556). Such a compound can not, however, lose water in the same way as the acid amide in the above reaction for the ammonia residue in an anilide contains only one hydrogen. Nevertheless anilides lose water but in a different way. In the case of the anilide of formic acid, i.e. formanilide, H—CO—NH—CeHs, the loss of water results in a compound in which the carbon and nitrogen remain linked to the benzene ring and an iso-cyanide or iso-nitrile is formed. The isonitrile is readily converted into the nitrile and the acid may then be obtained from that. 

In the laboratory amides are prepared by the reaction of ammonia with acid chlorides or, when available, acid anhydrides (Secs. 20.8 and 20.10). In industry they are often made by heating the ammonium salts of carboxylic acids. 

Introduction. The general methods for the preparation of amides are (1) ammonolysis of esters, acyl halides, and anhydrides (2) the dehydration of the ammonium salts of carboxylic acids ... 

The ammonolysis of acyl chlorides is commonly employed whenever the preparation of an amide is desired for the identification of a carboxylic acid. The acyl chloride is prepared and treated with aqueous ammonia, or, if the amide is very soluble in water, with ammonia in benzene. In the latter case the ammonium chloride is filtered off, and the amide obtained by evaporation of the benzene with powdered ammonium carbonate. The preparation of amides from carboxylic acids is based upon the formation of an equilibrium mixture when the ammonium salts of the acid are heated ... 

Removal of water by distillation shifts the equilibrium point to favor formation of the amide. For preparation of the amide by this method the ammonium salt of the carboxylic acid is prepared and dehydrated, melted, allowed to cool, and then pulverized. The powdered material is placed in a distilling flask and heated. Another method is to add solid ammonium carbonate to the carboxylic acid, and distill directly. 

It is well known that halomethyleneiminium salts, often prepared in situ (see Section 2.1.2.2) react with ammonium salts, primary amines, secondary amides, urea and IV-substituted ureas to afrbrd amidinium salts, from which the free amidines can be obtained by addition of bases. > 4 Some recent results are given below. Dimethylformamide chloride and other 7V,iV-disubstituted formamide chlorides were reacted with acetanilides, chloroacetanilides, 6-aminopenam derivatives, 2-aminopyrimidine, 4-aminouracil, 2-amino-4-chloropyridazine, 2-aminothiazole, 2-aminobenzothiazole and thiobenzamides to give the amidines via the amidinium salts. In the reaction of MA -disubstituted formamide chlorides with thiobenzamides the solvent seems to be decisive for the course of the reaction. In tertiary formamides the thiobenzamides are desulfurized to nitriles, whereas in CHCI3 or CCI4 amidinium salts (296 Scheme 45) are formed. From trimethylsilyl isocyanate and the fluorinated amine (297) the /V-fluorocarbonylamidine (298) is accessible. ... 

Phosphorylation. Chambers et al. found the reagent useful for the preparation of nucleoside diphosphoric acids (3, R —adenine, uracil, etc.). A nucleotide (I) is converted into the 5 -phosphoramidate (2) by reaction with ammonia and dicyclo-hexylcarbodiimide (DCC), and the amidate (2) is treated with dioxane diphosphate in o-chlorophenol (3 hrs..0 ). The diphosphoric acid (3) is precipitated with petroleum ether and purified as the ammonium salt. Yields are around 90%, whereas when 8.5% phosphoric add was used yields were in the order of 50-60%. However, anhydrous... 

REACTION PREPARATION OF AN ACID-AMIDE FROM THE AMMONIUM SALT OF THE ACID... 

The reaction involved in the preparation of an amide from the ammonium salt of the add is capable of general application. The latter is subjected to dry distillation, or more conveniently, heated in a sealed tube at 220-230° for five hours ... 

Since the aromatic amides are generally insoluble in water, they are usually prepared by the method just given, and not, as in the case of acetamide, by heating the ammonium salt of the acid. 

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