Data ArticleA novel use of Boc-Oxyma as reagent for tert‑butoxycarbonylation of amines and amino acid esters
Section snippets
Rationale
Nowadays, protecting groups have great importance in the synthesis of natural products [1], carbohydrates [2], and throughout the synthetic organic chemistry [3,4]. Amino group protection is very essential in the context of maintaining it as orthogonal protection in peptide synthesis [5]. Particularly, amine protection with tert‑butoxycarbonylation (Boc) is a widely used strategy. Various protection approaches exist for the diverse types of amino protecting groups for amines and amino acid
Material and methods
All the chemical substrates were purchased and utilized from Sigma Aldrich Company, USA. The reaction evolution was detected with TLC on silica gel poly-gram plates (STL G/UV-254). NMR spectra (1H & 13C NMR) was recorded with a Bruker Avance DPX (400 MHz) spectrometer in CDCl3 and DMSO‑d6 as solvents with TMS as internal standard. High resolution mass spectrum (HRMS) data were documented with a TOF-Q II ESI Bruker apparatus at ambient temperature. All the melting points of target molecules were
Optimization of reaction conditions
Initially, to achieve suitable conditions for the synthesis of N-Boc amines and amino acid esters, various reaction conditions were studied. The reagent is soluble in common organic solvents, such as tetrahydrofuran, acetonitrile, dichloromethane. To test the proof of principle, at the outset, 4-methyl aniline was subjected to reaction with Boc-Oxyma in dichloromethane as solvent and DIPEA as a base. The reaction progressed at room temperature only. TLC monitoring revealed that there was a
Conclusion
In conclusion, we have developed an efficient method for the protection of nitrogen under relatively milder, neat and faster conditions using a stable Boc-Oxyma. The present methodology has a wide substrate scope for tert‑butoxycarbonylation of simple and sterically hindered amines in high yields with good purities. Furthermore, this would preclude the handling of haloformates and Boc-anhydride. Therefore, we speculate that this would find numerous applications in the synthesis of complex
Declaration of Competing Interest
The authors declare no conflict of interest.
Acknowledgments
SM is thankful to the UGC-BSR research startup grant, Govt. of India, New Delhi, India for the financial support. All the authors are also thankful to Department of Chemistry, GITAM deemed to be university, Visakhapatnam, India and School of Chemistry, University of KwaZulu-Natal, Durban, South Africa for providing facilities.
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