Efficient solventless technique for Boc-protection of hydrazines and amines

Raju, M. Bhagavan; Mäeorg, Sirje; Tsubrik, Olga; Mäeorg, Uno

doi:10.3998/ark.5550190.0010.628

Cited by 12 publications

(2 citation statements)

References 6 publications

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“…PEG-400 has been found to be an adequate and eco-friendly reaction medium for the chemoselective transformation of amines to N-(tert-butoxycarbonyl) amines. Correlated to the previously reported methods, these both protocols (method A and B) offer several advantages such as mild reaction circumstances, easy operation, small reaction period, and high yield (Agami and Couty, 2003;Kelly and Mcneil, 1994;Pisár et al, 2018;Raju et al, 2009;Sharma et al, 2004;Varela et al, 2006). Some various procedures apply for the protection of secondary amine in pyrazole but only two methods (A and B) was succeeded and the other three (C, D, and E) were failed (Fig.…”

Section: Resultsmentioning

confidence: 89%

Green approach toward protection of secondary amine in pyrazole nucleus by PEG-400 and Boc catalyst

2020

J app pharm sci

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The objective of the present study is the protection of secondary amine in the substituted pyrazole derivative with the help of a green catalyst to facilitate the synthesis of anticancer compounds. Di-tert-butyl dicarbonate (Boc) has been used as a protecting agent with various catalysts such as Polyethylene glycols-400, Dimethyl aminopyridine, and N, N-Diisopropyl ethylamine. In this study, five different synthetic methods have been applied, but success has been achieved in only two. The very first method has been reported for the protection of secondary amine in pyrazole, associated with these catalysts. These synthetic methods had given a good yield and fewer side products, and it also a green approach toward synthetic chemistry.

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Section: Resultsmentioning

confidence: 89%

Green approach toward protection of secondary amine in pyrazole nucleus by PEG-400 and Boc catalyst

2020

J app pharm sci

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“…The reported synthesis of (S)-propranolol through AKR involved the use of BocNH 2 as nucleophile in 3 steps. 4b However, we prepared Boc-protected isoproylamine 16 and used it as nucleophile in the AKR of racemic naphthylglycidyl ether. Thus, we got the Boc-protected amino alcohol in 99% ee, which on deprotection directly gave (S)-Propranolol.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Asymmetric Aminolytic Kinetic Resolution of Racemic Epoxides Using Recyclable Chiral Polymeric Co(III)-Salen Complexes: A Protocol for Total Utilization of Racemic Epoxide in the Synthesis of (R)-Naftopidil and (S)-Propranolol

et al. 2013

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Chiral polymeric Co(III) salen complexes with chiral ((R)/(S)-BINOL, diethyl tartrate) and achiral (piperazine and trigol) linkers with varying stereogenic centers were synthesized for the first time and used as catalysts for aminolytic kinetic resolution (AKR) of a variety of terminal epoxides and glycidyl ethers to get enantio-pure epoxides (ee, 99%) and N-protected β-amino alcohols (ee, 99%) with quantitative yield in 16 h at RT under optimized reaction conditions. This protocol was also used for the synthesis of two enantiomerically pure drug molecules (R)-Naftopidil (α1-blocker) and (S)-Propranolol (β-blocker) as a key step via AKR of single racemic naphthylglycidyl ether with Boc-protected isoproylamine with 100% epoxide utilization at 1 g level. The catalyst 1 was successfully recycled for a number of times.

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