28022-43-7Relevant articles and documents
Synthesis of N,O-acetals by net amide C[sbnd]N bond insertion of aldehydes into N-acyl phthalimides and N-acyl azoles
Enright, Robert N.,Grinde, Jeffrey L.,Wurtz, Lincoln I.,Paeth, Matthew S.,Wittman, Tekoa R.,Cliff, Emily R.,Sankari, Yessra T.,Henningsen, Lucas T.,Tan, Chuchen,Scanlon, Joseph D.,Willoughby, Patrick H.
, p. 6397 - 6408 (2016)
We found that N-acyl phthalimides and several N-acylated azoles are capable of reacting with aldehydes to form O-acyl-N,O-acetals in an apparent amide C[sbnd]N bond insertion. In the context of N-acyl phthalimides, the reaction is mediated by substoichiometric amounts of sodium iodide and potassium phthalimide. DFT computations supported a proposed mechanism and provided insights into the effect of the alkali metal additive. This strategy could be used to prepare a myriad of N,O-acetals from a range of aldehydes. A one-pot procedure was also developed in which N-acyl phthalimide was generated in situ prior to forming the N,O-acetal product. The one-pot strategy was used to demonstrate that activated amides derived from imidazole, pyrazole, (benzo)triazole, and tetrazole are also amenable substrates. Collectively, these studies provide an approach to the synthesis of a variety of N,O-acetals under mild conditions from inexpensive starting materials.
Preparation method of levocetirizine
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Paragraph 0008; 0021, (2020/04/17)
The invention provides a preparation method of levocetirizine. The method comprises the following steps of: the step 1, carrying out a cyclization reaction on (R)-4-chlorodiphenyl methylamine and tris(2-chloroethyl)amine to obtain a compound represented by a formula (I); 2, performing condensation reaction of the compound shown in the formula (I) and 2-ethyl glycolate to obtain a compound shown ina formula (II); and the step 3, converting the compound shown in the formula (II) into levocetirizine. According to the preparation method, (R)-4-chlorodiphenyl methylamine and tris(2-chloroethyl)amine are taken as the initial raw materials, and cyclization reaction, condensation reaction and hydrolysis reaction are carried out so as to obtain levocetirizine. The synthetic route provided by the invention is short, the yield is high, and experimental results show that the yield of the levocetirizine prepared by the method provided by the invention can reach 47%, and the purity can reach 99.7%.
Enantioselective Hydrogenation of Diarylmethanimines for Synthesis of Chiral Diarylmethylamines
Kong, Duanyang,Li, Meina,Zi, Guofu,Hou, Guohua,He, Yong
, p. 6640 - 6648 (2016/08/16)
An enantioselective hydrogenation of N-substituted diarylmethanimines under mild conditions has been first realized by using an iridium catalyst with a chiral f-spiroPhos ligand. This method provides an efficient access to the asymmetric synthesis of a variety of chiral diarylmethylamines and their derivatives with excellent enantioselectivities (up to 99.4% ee) and high turnover numbers (TON up to 4000).
