82270-62-0Relevant articles and documents
Efficient transamidation of primary carboxamides by in situ activation with N,N-dialkylformamide dimethyl acetals
Dineen, Thomas A.,Zajac, Matthew A.,Myers, Andrew G.
, p. 16406 - 16409 (2006)
Two protocols for the transamidation of primary amides with primary and secondary amines, forming secondary and tertiary amides, respectively, are described. Both processes employ N,N-dialkylformamide dimethyl acetals for primary amide activation, producing N-acyl-N,N-dialkylformamidines as intermediates, as widely documented in the literature. Although the latter intermediates react irreversibly with amines by amidinyl transfer, we show that in the presence of certain Lewis acid additives efficient acyl transfer occurs, providing new and useful methods for amide exchange. In one protocol for transamidation, the N-acyl-N,N-dialkylformamidine intermediates are purified by flash-column chromatography and the purified intermediates are then treated with an amine (typically, 2.5 equiv) in the presence of scandium triflate (10 mol %) in ether to form in high yields the products of transamidation. In a second procedure, N-acyl-N,N-dialkylformamidines are generated in situ and, without isolation, are subjected to transamidation in the presence of zirconium chloride (0.5 equiv) and an amine (typically 2 equiv). A variety of different primary amides and amines are found to undergo efficient transamidation using the methods described.
Biocatalytic aminolysis of ethyl (S)-mandelate by lipase from Candida antarctica
Lima, Rafaely N.,Porto, André L.M.
, p. 157 - 163 (2017/07/12)
Enzymes play many roles in the advancement of biotechnology, discovery of new therapeutic agents and industrial processes. In this perspective, aminolysis reactions using lipase from Candida antarctica (CAL-B) were performed from ethyl (S)-mandelate and several aliphatic amines (45 °C, hexane, 3–6 h). By means of optimized conditions, amides with excellent isolated yields (60–97%) were synthetized. The biotechnological potential of CAL-B as a promising approach for the synthesis of organic compounds in a more sustainable, rapid, efficient and green chemistry perspective was verified on these results.
Enantioselective Synthesis of α-Hydroxy Amides and β-Amino Alcohols from α-Keto Amides
Mamillapalli, N. Chary,Sekar, Govindasamy
, p. 18584 - 18588 (2016/01/25)
Synthesis of enantiomerically enriched α-hydroxy amides and β-amino alcohols has been accomplished by enantioselective reduction of α-keto amides with hydrosilanes. A series of α-keto amides were reduced in the presence of chiral CuII/(S)-DTBM-SEGPHOS catalyst to give the corresponding optically active α-hydroxy amides with excellent enantioselectivities by using (EtO)3SiH as a reducing agent. Furthermore, a one-pot complete reduction of both ketone and amide groups of α-keto amides has been achieved using the same chiral copper catalyst followed by tetra-n-butylammonium fluoride (TBAF) catalyst in presence of (EtO)3SiH to afford the corresponding chiral β-amino alcohol derivatives.
