Primary alcohols reaction with, phosgene

SYNTHESIS The first step involves the s)mthesis of the amino acid 7-benzyl-L-glutamate by a standard Fischer esterification reaction of L-glutamic acid with benzyl alcohol in the presence of strong acid. The amino acid is subsequently converted to the N-carboxyanhydride (NCA) monomer by reaction with phosgene gas, or by reaction with the less hazardous compound triphosgene.The NCA is polymerized by initiation with a variety compounds such as primary and secondary amines, and alkoxides. Typical comonomers include other amino acid NCAs. 

Although numerous methods are known for the synthesis of carbamates of primary and secondary alcohols, they are not satisfactory for the preparation of carbamates of tertiary alcohols /-Butyl carbamate was first obtained by reaction of sodium /-butoxide with phosgene and tbionyl chloride at —60°, followed by reaction with concentrated aqueous ammonia, the overall yield was less than 20%. This procedure, however, was found to be unsuitable for the preparation of carbamates of other tertiary alcohols. Carbamates have been prepared by the... 

The nature of the alcohol also affects the nature of the products formed. Thus with most primary alcohols the reaction described above takes place, but if there are present in the molecule of the primary alcohol radicles of high molecular weight, partial decomposition of the carbonate takes place with formation of phosgene and the corresponding chlorocarbonic ester, as follows ... 

Barton devised a new method for the oxidation of primary alcohols to aldehydes involving in the first step conversion to the alkyl chloroformate (1) by adding a solution of the alcohol in ether to ether saturated with phosgene (15-20% w./v.) the solvent is removed at reduced pressure. If the alcohol is hindered, quinoline is added as catalyst and the quinoline hydrochloride removed by filtration. The next step, reaction with dimethyl sulfoxide, is attended with evolution of carbon... 

Reactions with nucleophiles other than alcohols can produce other carbonic acid derivatives. For example, reaction with anhydrous ammonia yields urea, 0 = C(NH2)2. Aromatic primary amines can, depending on reaction conditions, react with phosgene to form carbamoyl chlorides (Csuros et al., 1969). 

Other types of polycarbonates have also been made using a very different approach from that involving bisphenol A and related compounds. For example, the reaction between phosgene and allyl alcohol (CH2=CHCH2OH) produces a monomer with carbon-carbon double bonds at both ends of the molecule that can be used for polymerization. Interestingly enough, the polycarbonate produced by this process has very different physical properties from the traditional bisphenol A polymer. The allyl polymer is a clear, transparent, flexible plastic whose primary use is in the production of eyeglass lenses. 

The anhydrides 186 react with primary amines in alcohol and form compounds 187. The reaction of the latter with phosgene in pyridine (80°C) [104], in boiling benzene [109, 110], or in toluene (90°C) [111] leads to cyclization with the formation of 2,4-quinazolinedione derivatives 188 [104, 109-111],... 

Ureas and Carbonates. Reagent (1) may be used as a direct replacement for the highly toxic Phosgene in reactions with alcohols and amines. Reaction of (1) with two equivalents of a primary aliphatic or aromatic amine at room temperature rapidly yields a symmetrical urea (eq 9). If only one equivalent of a primary amine is added to (1), then the imidazole-Al-carboxamide (4) is formed (eq 10). These compounds can dissociate into isocyanates and imidazole, even at room temperature, and distillation from the reaction mixture provides a useful synthesis of isocyanates (eq 10).7 Secondary amines react only at one side of (1) at room temperature, again giving the imidazole-Al-carboxamide of type... 

Thus, the chloroformates of primary and secondary alcohols, prepared by reaction of the alcohol with phosgene, are reduced to the corresponding alkane in excellent yield on reaction with tri-n-propylsilane in the presence of t-butyl peroxide at 140 °C yields are low for aryl and benzyl alcohols. A method for the direct replacement of the hydroxy-group of alcohols by alkyl or aryl groups has been described (see Scheme 11, ref. 67). 

A phosgene-free process for preparing urethane and carbonate monomers and polymers has been reported [257]. The process involves reaction of CO2 with amines (e.g. 4,4 -methylenebis(cydohexylamine)), alcohols, or amino alcohols in the presence of an amidine- or guanidine-type base (e.g. N-cydohexyl-N, N, N",N"-tetra-ethylguanidine), followed by treatment of the resulting ammonium carbamate or carbonate salt with a primary or secondary hydrocarbyl halide of a specified structure in a polar, aprotic solvent (e.g. N-methylpyrroUdinone). When hydrocarbyl dihalides or -polyhalides are used in the second step, polyurethanes and polycarbonates are formed. 

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