Chemical Properties
Di-tert-butyl dicarbonate (Boc2O,24424-99-5
) and di-tert-butyl tricarbonate ((BocO)2CO) have been used as amine carbonylating reagents to obtain linear or branched aliphatic isocyanates.
most of the known methods for transforming amines into isocyanates are not mild enough and furnish undefined products as a result of uncontrolled side reactions. However, 4-dimethylaminopyridine (DMAP)-catalyzed reaction with activated carbonates as C1 building blocks constitutes a convenient laboratory method for the phosgene-free isocyanation of amines. A procedure has been described whereby alkyl- and arylamines are converted into isocyanates in high yields by reaction with activated carbonates (for example, di-tert-butyl dicarbonate, Boc2O) in the presence of a catalytic amount of a nucleophilic nitrogen base at room temperature.
Di-tert-butyl dicarbonate (Boc2O) is a widely used reagent for introducing protecting groups in peptide synthesis. The reaction of substituted anilines with Boc2O in the presence of a stoichiometric amount of 4-dimethylaminopyridine (DMAP) in an inert solvent (acetonitrile, dichloromethane, ethyl acetate, tetrahydrofuran, toluene) at room temperature leads to aryl isocyanates in almost quantitative yields within 10 min.
Chemical Properties
White to off-white microcrystalline powder
Uses
Reagent commonly used in organic chemistry for the introduction of the BOC protecting group.
Uses
reagent for t-BOC-protected amines
Uses
Reagent for the preparation of Boc-amino acids and peptides in high yields.
Application
Di-tert-butyl dicarbonate(24424-99-5) has the following uses:
(1) As part of a series of bovine plasma amine oxidase inactivators. Aminomethylenes were prepared by the reaction of Boc propargylamine with formaldehyde, diisopropylamine and copper bromide.
(2) It can be used as a general purpose carboxylation reagent. Carbon nucleophiles generated by a non-nucleophilic base (LDA) were effectively trapped with di-tert-butyl dicarbonate (Boc-anhydride) to provide the corresponding tert-butyl aryl acetates, di-tert-butyl aryl malonates, unsymmetrical aryl malonates and tert-butyl benzoates in high yields.
(3) Alcohols as Boc derivatives were catalytically protected by Lewis acids. Reagents for the introduction of Boc protecting groups.
(4) Reagents for the preparation of Boc-protected amines. Tri-tert-butoxycarbonyl-protected hydrazines prepare Fmoc esters in chromogenic reagents for monitoring solid-phase aldehydes.
Definition
ChEBI: Di-tert-butyl dicarbonate is an acyclic carboxylic anhydride. It is functionally related to a dicarbonic acid.
Preparation
The preparation of Di-tert-butyl dicarbonate is as follows:To a monoester sodium salt solution were added 2g of N, N-dimethylformamide, 1g of pyridine, 1g of triethylamine,Cooling to -5~0°C, 60g diphosgene was slowly added dropwise within 1.5h dropwise addition was complete, warmed to room temperature (25°C), incubated for 2h, the reaction was allowed to stand after filtration, washing organic solution. Dried with anhydrous magnesium sulfate, the solvent was distilled off at atmospheric pressure to give crude product 65~70g. After cooling and crystallization, 57-60g of di-tert-butyl dicarbonate were obtained in a yield of 60-63%.
General Description
Di-tert-butyl dicarbonate (Boc2O) is a reagent mainly used for the introduction of the Boc protecting group to amine functionalities. It is also used as a dehydrating agent in some organic reactions, particularly with carboxylic acids, certain hydroxyl groups, or with primary nitroalkanes.
Hazard
An irritant that may cause serious eye injury; May cause skin sensitization; Highly toxic by inhalation
Flammability and Explosibility
Flammable
Purification Methods
Melt the ester by heating at ~35o, and distil it in a vacuum. If IR and NMR ( 1810m 1765 cm-1 , in CCl4 1.50 singlet) suggest very max impure, then wash with an equal volume of H2O containing citric acid to make the aqueous layer slightly acidic, collect the organic layer and dry it over anhydrous MgSO4 and distil it in a vacuum. [Pope et al. Org Synth 57 45 1977, Keller et al. Org Synth 63 160 1985, Grehn et al. Angew Chem 97 519 1985.] FLAMMABLE.
