The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Molecular Basis for the Stereoselective Ammonolysis of N-Alkyl Aziridine-2-Carboxylates Catalyzed by Candida antarctica Lipase B》. Authors are Park, Jae-Hoon; Ha, Hyun-Joon; Lee, Won Koo; Genereux-Vincent, Tobie; Kazlauskas, Romas J..The article about the compound:(S)-Propane-1,2-diamine dihydrochloridecas:19777-66-3,SMILESS:C[C@H](N)CN.[H]Cl.[H]Cl).Reference of (S)-Propane-1,2-diamine dihydrochloride. Through the article, more information about this compound (cas:19777-66-3) is conveyed.
Candida antarctica lipase B was used to catalyzed a stereoselective ammonolysis of N-(alkyl)aziridine-2-carboxylates in tert-butanol with ammonia and yielded (2S)-2-aziridinecarboxamide and remaining (2R)-2-aziridinecarboxylic acid ester. Varying the N-1 substituent on the aziridine ring changed the rate and stereoselectivity of the reaction. Substrates with a benzyl substituent or a (1R)-1-phenylethyl substituent reacted approx. ten times faster than substrates with a (1S)-1-phenylethyl substituent. Substrates with a benzyl substituent showed little stereoselectivity (E = 5-7) while substrates with either a (1R)-1-phenylethyl or (1S)-1-phenylethyl substituent showed high stereoselectivity (D > 50). Mol. modeling by using the current paradigm for enantioselectivity-binding of the slow enantiomer by an exchange-of-substituents orientation-could not account for the exptl. results. However, modeling an umbrella-like-inversion orientation for the slow enantiomer could account for the exptl. results. Steric hindrance between a Me group in the (1S)-1-phenylethyl substituent and Thr138 and Ile189 in the acyl-binding site likely accounts for the slow reaction. Enantioselectivity likely stems from an unfavorable interaction of the methine hydrogen with Thr40 for the slow enantiomer and from subtle differences in the orientations of the other three substituents. This success in rationalizing the enantioselectivity supports the notion that an umbrella-like-inversion orientation can contribute to enantioselectivity in lipases.
In some applications, this compound(19777-66-3)Reference of (S)-Propane-1,2-diamine dihydrochloride is unique.If you want to know more details about this compound, you can contact with the author or consult more relevant literature.
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Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider