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Benzyl Chloroformate

Other Names:

Benzyloxycarbonyl chloride

Benzyl chloroformate

Carbobenzoxy chloride


General Information:


CAS Number: 501-53-1

Molecular Weight: 170.59 g/mol

Appearance: Colorless to yellow liquid

Boiling Point: 103 C at 20 mmHg

Density: 1.195 g/mL at 25 C

Benzyl chloroformate is typically used for the Cbz protection of amines. It is a lachrymator and should be handled in a fume hood. A similar reagent is benzyl N-succinimidyl carbonate (Cbz-OSu).

Common Uses:

Reagent in the Cbz protection of amines

Procedure excerpt:

To a mixture of the crude SM (~10 g) in THF (~1 L) was added 2N NaOH (168 mL) and benzyl chloroformate (30.2 g, 176.8 mmol). After stirring 1 h, the biphasic . . .

[full procedure]


Benzyl chloroformate is a lachrymator that can cause serious damage to eyes and skin on contact. Inhalation is very harmful to the upper respiratory tract and lungs, and may be fatal (if exposure is sufficient). Benzyl chloroformate is also a suspected carcinogen.


1) Patent Reference: WO2003061598, page 23, (3.5 MB)

2) Wikipedia: Benzyl chloroformate (link)

3) Benzyl chloroformate (link)

4) A15682 Benzyl chloroformate, 95%, stab. with ca 0.1% sodium carbonate (link)

5) Pearson, A. J.; Roush, W. R.; Handbook of Reagents for Organic Synthesis; Activating Agents and Protecting Groups