With benzyl chloroformate

Presumably, reaction of chloride ion with benzyl chloroformate formed benzyl chloride. 

Functional group protection. The NH— group in proline is protected by acylation in the usual Schotten-Baumann manner with benzyl chloroformate to yield the benzyloxycarbonyl derivative (42). Correspondingly the —C02H group in glycine is protected by esterification in ethanol to form the ethyl ester, obtained as the hydrochloride (43) under Fischer-Speier conditions. 

Mixed carboxylic-carbonic anhydrides decompose in the presence of DMAP to give esters and carbon dioxide under mild conditions [Scheme 6,51], In the case of benzyl esters, the mixed car boxy lic-car bon ic anhydrides can be generated by reaction of the carboxylic acid with benzyl chloroformate in the presence of triethylamine (1.1 equiv) and DMAP (0.1 equiv)126 or more conveniently by reaction of the carboxylic acid with dibenzyl dicarbonate (dibenzyl pyrocarbo-nate) in THF or ferf-butyl alcohol in the presence of DMAP (0.1 equiv).127 The reactions generally work well except for hindered carboxylic acids. The method can also be used to make methyl, ethyl, ferf-butyl and ally esters. Carboxylic acids react with 2 equivalents of benzyl 2,2t2-trichloroacetimidate12s in the presence of a catalytic amount of boron trifluoride etherate to give the benzyl ester in modest to good yield,12g... 

Steric hindrance significantly retards the rate of N-acylation of a-branched amino acids using benzyl chloroformate under the usual Schotten-Baumann conditions. because the benzyl chloroformate hydrolyses faster than it reacts with the amino group. Simultaneous protection of the amino group as its Cbz derivative and the carboxylic acid as its benzyl ester can be accomplished by heating the amino acid with benzyl chloroformate in DM SO with a catalytic amount of DMAP (Scheme 8.70].172... 

During a synthesis of a-amino acids harbouring an adenine group in the side chain, difficulty was encountered protecting the N6-amino group as its Cbz derivative [Scheme 8.73].179 Treatment with benzyl chloroformate under all the... 

Explain the formation of the benzyl ester 242 from the reaction of the dicar-boxylic add 241 with benzyl chloroformate and pyridine. 

The difficult preparation of Z-Arg(Z)2-OH, and thus the related low yields associated with earlier methods,f l are conveniently bypassed if persilylated A -(benzyloxy-carbonyl)arginine is acylated with benzyl chloroformate.f 1 This procedure is also well-suited for the preparation of Boc-Arg(Z)2-OH.P l Alternatively, the N -bis-protected derivatives are also obtained in good yields via guanidinylation of N -protected ornithine with N,N -bis-protected guanidinylating reagents (see Section 2.6.1.6).t l For peptide acylation steps, both Z-Arg(Z)2-OH and Boc-Arg(Z)2-OH are mainly used as active esters,f l mixed anhydrides or carbodiimides.P l... 

The 2-chloroimidazole 240 undergoes chlorine-lithium exchange to give the 2-lithiated species which could then be quenched by an electrophile with benzyl chloroformate 241 the imidazole-2-carboester 242 was obtained (Scheme 57) <2005BML1441>. 

Piperazine reacts with benzyl chloroformate to give l-(benzyloxycarbonyl)-piperazine (1690), with benzyl chloride (1 mol) (and piperazine dihydrochloride) to 1 -benzylpiperazine (1691-1693), with ethyl chloroformate and sodium hydroxide to 1,4-diethoxycarbonylpiperazine, which with sodium benzyl oxide gave 1,4-dibenzyloxycarbonylpiperazine (1694), and with cyanogen to 1,4-bis(C-cyano-C-iminomethyl)piperazine (139) (1695). The piperazine-chlorotrimethylsilane adduct with triethylamine gave l,4-bis(trimethylsilyl)piperazine (1696), and piperazine in... 

A-Acyl oxaziridines can be prepared by treatment of solutions of A-unsubstituted oxaziridines with acid chlorides, acetic anhydride or isocyanates <91S327>. Vederas and co-workers prepared A-benzyloxycarbonyl-3-phenyloxaziridine (53c) by the direct in situ acylation of 3-phenyloxaziridine (189) with benzyl chloroformate (Scheme 35) <93TL6859>. Although the overall yield is low, for example 12%, it is claimed that reasonable amounts of (53c) are easily accessible. 

Try to anticipate the formation of azeotropes when distillation and concentration occur. Unexpected azeotropes may cause unsafe operations. For instance, distillative removal of water from the reaction of an amine with benzyl chloroformate (PhCH2COCl) resulted in formation of an azeotrope of water and benzyl chloride, a common impurity in benzyl chloroformate [40]. 

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