Benzyl chloroformate
- Benzyl chloroformate
- Benzyloxycarbonylchloride
- Z- chloride
- CAB
Colorless, pungent -smelling fluid
Liquid
1.20 g · cm -3
-18 ° C.
179 ° C
9.5 hPa (86 ° C)
- Violent decomposition with water
1.5190 (20 ° C)
Risk
Template: Infobox chemical / molecular formula search available
Benzyl chloroformate, benzyl chloroformate also often referred to as Chlorkohlensäurebenzylester correct, is an organic chemical substance. It is a monoester of carbonic acid at the same time to the substance group of carboxylic acid chlorides. In the synthesis of peptides is benzyl chloroformate as reagent to introduce the benzyloxycarbonyl protecting group which is usually used for protection of amino groups.
Properties
Benzyl chloroformate is a pungent and suffocating odor, lachrymatory liquid. It is soluble in most organic solvents, but is decomposed solvolytically by protic solvents such as water or alcohols. With alcohols to form carbonic acid esters. With benzyl amines react to form urethanes.
Use
In organic synthesis chemistry, and especially in the peptide synthesis, the benzyloxycarbonyl group with benzyl chloroformate is introduced in the presence of a weak base. The benzyloxycarbonyl group is in structural formulas usually as Cbz, Cbo, or Z group (named after the discoverer, Leonidas Zervas ) abbreviated.
The protected amine can be deprotected by catalytic hydrogenation to hydrogenolytic cleavage of the benzyl heteroatom bond, followed by decarboxylation of the resulting unstable carbamic acid, or treatment with acids again.
Nomenclature
The common name " chloroformate " is not entirely correct, as it strictly speaking a derivative of carbonic acid is not a derivative of formic acid. Strictly speaking, this is a monochloride and at the same time the monobenzyl ester of carbonic acid.
Hazards
Since benzyl decomposed by humidity and on the skin hydrolytically to form hydrochloric acid, it is highly corrosive on contact. Inhaled, it can lead to pulmonary edema.
Commercially available benzyl includes the preparation, the as carcinogenic classified benzyl chloride as an impurity. Some manufacturers, such as Merck KGaA, therefore also refer to the benzyl as carcinogenic and give next to the hazardous substance symbols T (toxic ) and N ( dangerous for the environment ), the R -phrases 45-34 - 50/ 53 and the S-phrases 53 - 26 - 36/37/39 - 45 - 60 - 61Vorlage: to S-Sätze/Wartung/mehr than 5 sets.