Mild Approach to the Deprotection of Troc from Protected Amines Using Mischmetal and TMSCl

Abstract

The 2,2,2-trichloroethoxycarbonyl (Troc) protecting group was efficiently removed from Troc-protected aliphatic and aromatic amines and also some Troc, Tos- and Troc, Ac-protected amines using activated mischmetal (MM). All reactions were performed by refluxing in dry tetrahydrofuran under an argon atmosphere and gave moderate to excellent yields. Several new compounds were synthesized, and new data about reactivity of Troc group were obtained.

Keywords:

• Amines
• deprotection
• mischmetal
• TMSCl
• Troc

ACKNOWLEDGMENT

We thank the Estonian Science Foundation for financial support (Grant Nos. 6706 and 8031).

Notes

^a The identity of products (B 1, 5, 6) were confirmed by GC, and IR spectroscopy and the rest of the products were confirmed by ¹H NMR and/or ¹³C NMR spectroscopy.

^b In the reaction of number 3, 4 mmol of MM and 6.2 mmol of TMSCl were used instead of optimized conditions.

^c New compounds (A 3, 4, 7, 9, 11) were identified by HR mass spectrometry.

^d The yields of the products 9B and 11B were determined after purification of the crude product by column chromatography.

^e Brine was used for washing the extract instead of distilled H₂O.