Amines carbon

A simpler nonphosgene process for the manufacture of isocyanates consists of the reaction of amines with carbon dioxide in the presence of an aprotic organic solvent and a nitrogeneous base. The corresponding ammonium carbamate is treated with a dehydrating agent. This concept has been apphed to the synthesis of aromatic and aUphatic isocyanates. The process rehes on the facile formation of amine—carbon dioxide salts using acid haUdes such as phosphoryl chloride [10025-87-3] and thionyl chloride [7719-09-7] (30). 

A variant on this structure, dioxyline, has much the same activity as the natural product but shows a better therapeutic ratio. Reduction of the oxime (113) from 3,4-dimethoxyphenyl-acetone (112) affords the veratrylamine homolog bearing a methyl group on the amine carbon atom (114). Acylation of this with 4-ethoxy-3-methoxyphenyl acetyl chloride gives the corresponding amide (115). Cyclization by means of phosphorus oxychloride followed by dehydrogenation over palladium yields dioxyline (116). ... 

The above equation adequately accounts for the action of ammonia, but it may function in other ways as well, for a variety of bases, such as tertiary amines, carbonates (46), and hydroxides 20,32), also suppress formation of coupled products. Greenfield (28) suggested that bases may function by suppressing the hydrogenolysis reaction leading to secondary and tertiary amines. 

Once neutralization capacity is considered, the next factor is the solubility of amine carbonates formed by neutralization. This characteristic varies by product and temperature. 

When a carbonyl group is bonded to a substituent group that can potentially depart as a Lewis base, addition of a nucleophile to the carbonyl carbon leads to elimination and the regeneration of a carbon-oxygen double bond. Esters undergo hydrolysis with alkali hydroxides to form alkali metal salts of carboxylic acids and alcohols. Amides undergo hydrolysis with mineral acids to form carboxylic acids and amine salts. Carbamates undergo alkaline hydrolysis to form amines, carbon dioxide, and alcohols. 

Tertiary amine accelerated polymercaptan/ epoxy systems, 10 410 Tertiary amine-carbonate technology,... 

Keywords Silane coupling agents alkylammonium carbamates aminosilane-carbon dioxide salts amine-carbon dioxide salts. 

Many investigations of the molecular structure of thin films formed by y-APS deposited onto inorganic substrates from aqueous solutions have been carried out. Ondrus and Boerio [2] used reflection-absorption infrared spectroscopy (RAIR) to determine the structure of y-APS films deposited on iron, 1100 aluminum, 2024 aluminum, and copper substrates from aqueous solutions at pH 10.4. They found that the as-formed films absorbed carbon dioxide and water vapor to form amine bicarbonate salts which were characterized by absorption bands near 1330, 1470, 1570, and 1640 cm-1. y-APS films had to be heated to temperatures above about 90°C in order to dissociate the bicarbonates, presumably to free amine, carbon dioxide, and water. Since the amine bicarbonates failed to react with epoxies, the strength of adhesive joints prepared... 

Deprotonation of the secondary amino group of 2,5 -iminonucleosides 69 (X = NR1 R1 = Me, Ph, PhCH2 R= Me, Ph) (Scheme 11) created the nucleophilic center which attacked intramolecularly the aminal carbon atom of 69 producing the uracil derivatives 70 in moderate yields <1990J(P1)3027>. 

Unlike many other type of radical addition reactions, the product is most often an alkyl-cobalt(III) species capable of further manipulation. These product Co—C bonds have been converted in good yields to carbon-oxygen (alcohol, acetate), carbon-nitrogen (oxime, amine), carbon-halogen, carbon-sulfur (sulfide, sulfinic acid) and carbon-selenium bonds (equations 179 and 180)354. Exceptions to this rule are the intermolecular additions to electron-deficient olefins, in which the putative organocobalt(III) species eliminates to form an a,/ -unsaturated carbonyl compound or styrene353 or is reduced (under electrochemical conditions) to the alkane (equation 181)355. 

Azine approach. C-l and C-3 in the ring system can be regarded as aminal carbons the ring system is formed accordingly. The perhydro derivative (628) can be formed from acetaldehyde and perhydropyridazine (72JA7108). 

Carbamate complexes are synthesized by carbonation of metal dialkylamides (equation 20), or by reaction of the appropriate amine, carbon dioxide, and a metal halide (equation 21). In both cases, it has been suggested that the reaction involves combination of the amine and carbon dioxide to form the carbamate anion, followed by anion exchange. ... 

Thirty-nine different dithiocarbamates have been efficiently prepared through a one-pot reaction of an aliphatic primary or secondary amine, carbon disulfide and an alkyl halide (Figure 2.16). " Typically, all reagents were liquids and the mixture slowly solidified upon reaction. Therefore, although the reaction does not use solvents, the reagents are probably acting as the solvent in this procedure. Additionally, the reactions were quenched with water and extracted with ethyl acetate, so solvent was used. Nevertheless, this is an excellent synthetic method for the preparation of S-alkyl dithiocarbamates, which are useful compounds for the pharmaceutical and agrochemical industries. 

Synthesis of ureas. Ureas can be synthesized by the reaction of aliphatic amines, carbon monoxide, and oxygen with selenium as a catalyst. For example, n-butylamine (0.1 mole) is dissolved in THF (100 ml.) amorphous selenium (0.005 g.-atom) is added and carbon monoxide is blown through the solution. Then oxygen (or air) is blown through. 1,3-Di-n-butylurea is obtained in stoichiometric yield. The reaction proceeds in two steps as formulated. 

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