A simple and robust one-pot nucleophilic addition–ring contraction of α-bromo N-sulfonylpyrrolidinones has been achieved toward α-carbonylated N-sulfonylazetidines. In the presence of potassium carbonate, various nucleophiles, such as alcohols, phenols or anilines, have been efficiently incorporated into the azetidine derivatives. Moreover, the α-bromopyrrolidinone precursors could be selectively obtained
The synthesis of benzosultams has been achieved through a gold(I)-catalyzed ammonium formation strategy. Starting from easily available N-(2-alkynyl)phenylsulfonyl azetidine derivatives, a cyclization reaction generated a spiroammonium gold intermediate that was ring-opened by nucleophilic alcohol or indole. This new methodology is compatible with the large variation in the substrates and nucleophiles
N-sulfonylated lactams of various ring sizes (from 5- to 8-membered rings) followed by a ring contraction reaction. The selective monohalogenation of N-sulfonyl lactams has been achieved in modest to excellent yields (9 examples, 39–96%) using N-halogenosuccinimides via the in situ generation of trimethylsilyl ketene aminal derivatives. The so-obtained α-halogeno N-sulfonyl lactams were engaged in
efficiently synthesized from readily available 1-(N-sulfonylazetidin-2-yl) ynones via gold(I)-catalyzedcyclization/nucleophilic substitution in the presence of various nucleophiles, such as water, alcohols, or indoles. Additionally, 3-iodopyrrolin-4-one derivatives have also been obtained under the same reaction conditions upon addition of 1.2 equiv of N-iodosuccinimide.
There is disclosed are an enzyme preparation characterized by a polymer carrier having fine pores with average radius of 200-500 Å and the enzyme is capable of converting an N-substituted cyclic imino ester into an (S)—N-substituted cyclic imino acid, thereby an (S)—N-substituted cyclic imino acid is preferentially produced, and has an amino acid sequence as set forth in SEQ ID NO: 1 or the like.
本发明公开了一种酶制剂,其特征在于具有平均半径为200-500Å的细孔的聚合物载体,并且该酶能够将N-取代的环状亚氨酸酯转化为(S)-N-取代的环状亚氨酸,从而优先产生(S)-N-取代的环状亚氨酸,并具有SEQ ID NO:1或类似的氨基酸序列。