177172-48-4Relevant articles and documents
Continuous-Flow Amide and Ester Reductions Using Neat Borane Dimethylsulfide Complex
?tv?s, Sándor B.,Kappe, C. Oliver
, p. 1800 - 1807 (2020/02/27)
Reductions of amides and esters are of critical importance in synthetic chemistry, and there are numerous protocols for executing these transformations employing traditional batch conditions. Notably, strategies based on flow chemistry, especially for amide reductions, are much less explored. Herein, a simple process was developed in which neat borane dimethylsulfide complex (BH3?DMS) was used to reduce various esters and amides under continuous-flow conditions. Taking advantage of the solvent-free nature of the commercially available borane reagent, high substrate concentrations were realized, allowing outstanding productivity and a significant reduction in E-factors. In addition, with carefully optimized short residence times, the corresponding alcohols and amines were obtained in high selectivity and high yields. The synthetic utility of the inexpensive and easily implemented flow protocol was further corroborated by multigram-scale syntheses of pharmaceutically relevant products. Owing to its beneficial features, including low solvent and reducing agent consumption, high selectivity, simplicity, and inherent scalability, the present process demonstrates fewer environmental concerns than most typical batch reductions using metal hydrides as reducing agents.
General strategy for large-scale synthesis of (+)-rivastigmine and (+)-NPS R-568
Rao, Ramakrishna,Shewalkar, Mukesh Padmakar,Nandipati, Ramadevi,Yadav, Jhillu Singh,Khagga, Mukkanti,Shinde, Devanand Baburao
experimental part, p. 589 - 598 (2011/11/29)
An economically viable strategy for the total synthesis of (+)-rivastigmine and (+)-NPS R-568 has been reported. The strategy involves regioselective hydrogenation of diastereomerically pure bis amine to realize the desired a-methyl chiral substituted benzyl amine. The route is economical, scalable, and versatile enough to be adapted to similar classes of compounds. Taylor & Francis Group, LLC.
Chemoenzymatic synthesis of the calcimimetics (+)-NPS R-568 via asymmetric reductive acylation of ketoxime intermediate
Han, Kiwon,Kim, Yunwoong,Park, Jaiwook,Kim, Mahn-Joo
scheme or table, p. 3536 - 3537 (2010/08/07)
A practical and efficient procedure for the synthesis of a potent calcimimetic (+)-NPS R-568 was developed. This procedure includes as the key step the asymmetric reductive acylation of a ketoxime intermediate catalyzed by a Pd nanocatalyst and a lipase i
