Carbonates with amines

Burgel, T., andFedtke, M. Reactions of Cyclic Carbonates with Amines Model Studies for Curing Process, Polym. Bull. 27 (1991) 171-177. 

The expected reactions of the cyano group attached to triazine ring carbon with amine, alcohol, and azide nucleophiles have been described <90NKK396>. Reduction of ketone to alcohol with sodium borohydride <88HCA712> and trichloromethyl groups to methyls with lithium aluminum hydride are also reported <86MI 6l2-02>. 

Because nitrogen nucleophiles can complex with palladium(O) and thereby deactivate the catalyst, it appeared necessary to study the palladium(0)-catalyzed reaction of allyl carbonates with amines. Without deactivation of the catalyst, the reaction of [11a,b] with piperidine led to the piperidine conjugate [39] in a yield of 73% as a mixture of regioisomers (Eq. 19). 

Figure 6.7 Reaction of a Cyclic Carbonate with Amine (18)...

Fig. 11 Synthesis of glycopolymers by reaction of polymers bearing reactive p-nitrophenyl carbonate with amine functional sugar...

The two diasteromeric allyliridium-phosphoramidite complexes formed in the allylic 5 2 substitution of /-substituted allylic acetates, benzoates, or carbonates, with amine nucleophiles have been synthesized and characterized by NMR and X-ray diffractions. Kinetic and stereochemical studies using deuterated substrates indicate that the reaction, which occurs with a retention of configuration, proceeds by the mechanism in Scheme 3. This iridium-catalysed reaction is compared to molybdenum- and palladium-catalysed reactions. 

CO. Alkynes will react with carbon monoxide in the presence of a metal carbonyl (e.g. Ni(CO)4) and water to give prop>enoic acids (R-CH = CH-C02H), with alcohols (R OH) to give propenoic esters, RCH CHC02R and with amines (R NH2) to give propenoic amides RCHrCHCONHR. Using alternative catalysts, e.g. Fe(CO)5, alkynes and carbon monoxide will produce cyclopentadienones or hydroquinols. A commercially important variation of this reaction is hydroformyiation (the 0x0 reaction ). 

Anion-exchange resins contain a basic radical, such as —NH and =NH, and are prepared by the condensation of formaldehj de with amines such as m-phenylenediainine and urea. These resins can absorb acids by the formation of salts, —NH3CI and =NHjCl, and are regenerated by treatment with sodium hydroxide or sodium carbonate. 

Amines are powerful nucleophiles which react under neutral or slightly basic conditions with several electron-accepting carbon reagents. The reaction of alkyl halides with amines is useful for the preparation of tertiary amines or quaternary ammonium salts. The conversion of primary amines into secondary amines is usually not feasible since the secondary amine tends towards further alkylation. 

Allylation under basic conditions. Allylation can be carried out under basic conditions with allylic acetates and phosphates, and under neutral conditions with carbonates and vinyloxiranes. The allylations under neutral conditions are treated separately in Section 2.2.2.1 from those under basic conditions. However, in some cases, allylations of the same substrates are carried out under both basic and neutral conditions to give similar results. These reactions are treated together in this section for convenience. Allylic acetates are widely used for Pd-catalyzed allylation in the presence of bases tertiary amines or NaH are commonly used[6,7,4l]. As a base, basic alumina or ICF on alumina is conveniently used, because it is easy to remove by filtration after the reaction[42]. Allyl phosphates are more reactive than acetates. The allylation with 40 proceeds stepwise. At first allylic phosphate reacts with malonate and then allylic acetate reacts with amine to give 41(43]. 

Monsanto has disclosed the use of carbon dioxide—amine complexes which are dehydrated, at low temperatures, with phosphoryl chloride [10025-87-3] or thionyl chloride [7719-09-7] as a viable route to a variety of aUphatic isocyanates. The process rehes on the facile formation of the intermediate salt (30).REPLACEVariations of this process, in which phosgene is used as a dehydrating agent, have been reported earlier (84). Table 2 Hsts commercially available aUphatic isocyanates. 

Carbon monosulfide, CS, which can be produced by passiag CS2 through a high voltage discharge, can react with C H SCl at low temperatures ia toluene to give CgH SC(S)Cl. In a similar manner CS reacts with S2CI2 by double iasertion to yield C1C(S)SSC(S)C1 (9). Carbon monosulfide can also react with amines or thiols ia toluene or DMF (10). A review of the synthetic utiUty of CS has been pubUshed (11). 

The process is capable of achieving higher solubiHties of CO2 in the solution without the corrosion problems encountered with amine systems before the advent of Amine Guard. The Sulfinol process is used in over 50 plants worldwide nevertheless, it is used less often than the amine or carbonate processes. 

Reaction with Amines and Ammonia. Carbonates react with amines and ammonia to produce carbamates or ureas. This reaction can be used as an alternative route to producing carbamate pesticides. 

One way of improving the adhesion between polymer and filler is to improve the level of wetting of the filler by the polymer. One approach, which has been used for many years, is to coat the filler with an additive that may be considered to have two active parts. One part is compatible with the filler, the other with the polymer. Probably the best known example is the coating of calcium carbonate with stearic acid. Such coated or activated whitings have been used particularly with hydrocarbon rubbers. It is generally believed that the polar end attaches itself to the filler particle whilst the aliphatic hydrocarbon end is compatible with the rubbery matrix. In a similar manner clays have been treated with amines. 

Carbonates, like esters, can be cleaved by basic hydrolysis, but generally are much less susceptible to hydrolysis because of the resonance effect of the second oxygen. In general, carbonates are cleaved by taking advantage of the properties of the second alkyl substituent (e.g., zinc reduction of the 2,2,2-trichloroethyl carbonate). The reagents used to introduce the carbonate onto alcohols react readily with amines as well. As expected, basic hydrolysis of the resulting carbamate is considerably more difficult than basic hydrolysis of a carbonate. 

It was anticipated that fragments 147 and 214 could be united through an amide bond linking the nitrogen atom of the latter with C-8 of the former. Indeed, the active ester formed by treatment of carboxylic acid 147 with 1,3-diisopropylcarbodiimide and 1-hydro-xybenzotriazole reacts efficiently with amine 214 to afford dihydroxy amide 215 in 95 % yield. This convergent union creates a molecule that possesses all but two carbon atoms of the natural product. 

A carbon-selenium bond can also be formed [106] by Diels-Alder reaction of the transient selenonitroso species 106 generated by phenylsulfinylselenylchlor-ide reacting with amines or trimethylsilylated amines. Selenonitroso compounds 106 were trapped with 2,3-dimethylbutadiene to afford 1,2-selenazine derivatives 107 (Scheme 2.44) in low yield. 1,2- Selenazines are interesting compounds which are quite unstable (2-3 h), except for the one having an... 

Allyl silanes react with epoxides, in the presence of Bp3-OEt2 to give 2-allyl alcohols. The reaction of a-bromo lactones and CH2=CHCH2Si SiMe3)3 and AIBN leads to the a-allyl lactone. " Benzyl silanes coupled with allyl silanes to give ArCH2—R derivatives in the presence of VO(OEt)Cl2 " and allyltin compounds couple with allyl silanes in the presence of SnCU. " Allyl silanes couple to the a-carbon of amines under photolysis conditions. ... 

The SnI reactions do not proceed at bridgehead carbons in [2.2.1] bicyclic systems (p. 397) because planar carbocations cannot form at these carbons. However, carbanions not stabilized by resonance are probably not planar SeI reactions should readily occur with this type of substrate. This is the case. Indeed, the question of carbanion stracture is intimately tied into the problem of the stereochemistry of the SeI reaction. If a carbanion is planar, racemization should occur. If it is pyramidal and can hold its structure, the result should be retention of configuration. On the other hand, even a pyramidal carbanion will give racemization if it cannot hold its structure, that is, if there is pyramidal inversion as with amines (p. 129). Unfortunately, the only carbanions that can be studied easily are those stabilized by resonance, which makes them planar, as expected (p. 233). For simple alkyl carbanions, the main approach to determining structure has been to study the stereochemistry of SeI reactions rather than the other way around. What is found is almost always racemization. Whether this is caused by planar carbanions or by oscillating pyramidal carbanions is not known. In either case, racemization occurs whenever a carbanion is completely free or is symmetrically solvated. 

Carbon dioxide reacts with amines (ArNH2) and iodoethane, under electrolysis conditions, to give the corresponding carbamate, (ArNHC02Et). Urea derivatives were obtained from amines, CO2, and an antimony catalyst. ... 

CDI and the other A /V -carbonylbisazoles of sufficiently high reactivity react with alcohols ROH to produce diesters of carbonic acid RO-CO-OR, and with amines R R2NH to give diamides of carbonic acid (ureas) R N-CO-NR 2. By use of corresponding bifunctional partners, heterocyclic systems are accessible through insertion of the carbonyl group between two heteroatoms (see Chapter 7). 

Zinc carbamate complexes are well known, and the structural types and stabilities can be compared with thiocarbamates and dithiocarbamates which are discussed in Sections 6.8.11.1.3 and 6.8.7.1.4482 Carbamates of zinc can be formed from the reaction of carbon dioxide with alkylzinc alkyl amides and further reaction with alkylzinc can give a distorted cubane structure.483 The tetrameric diethylcarbamate species initially formed can also be used to produce monomeric or dimeric carbamate structures in reaction with amines tetramethylethylenediamine forms a monomer [(Me2NCH2)2Zn(02CN(C2H5)2)2] with an octahedral zinc center and pyridine forms a dimer[CsH5NZn2Me(02CN(C2H5)2)3] with tetrahedral zinc centers.484... 

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