178946-64-0

Upstream product

• 98-59-9 p-toluenesulfonyl chloride 
• 10019-95-1 N-tosylpyrrolidinone 
• 178946-63-9 methanesulfonic acid (R,S)-1-(4-methyl-phenylsulfonyl)-2-oxo-pyrrolidin-3-yl ester 
• 1643-19-2 tetrabutylammomium bromide 

Downstream Products

• 17330-25-5 methyl 1-p-tosylazetidine-2-carboxylate 
• 10019-95-1 N-tosylpyrrolidinone 
• 39897-13-7 1-(p-tolylsulfonyl)azetidine-2-carboxylic acid 

Relevant academic research and scientific papers

Synthesis of 2-carboxylated aza-ring derivatives through α-monohalogenation/ring-contraction of N-sulfonyl lactams

2-Carboxylated aza-rings have been synthesized in two steps through a highly selective monohalogenation of 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 a ring opening/ring closing reaction in the presence of various alcohols or anilines under basic conditions affording 2-carboxylated aza-rings, such as azetidine, pyrrolidine or piperidine derivatives in high yields (24 examples, 61–99%).

Robust synthesis of N-sulfonylazetidine building blocks via ring contraction of α-bromo N-sulfonylpyrrolidinones

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 in good yields by monobromination of cheap and easily available N-sulfonyl-2-pyrrolidinone derivatives.

Cephalosporin antibiotics

The present invention relates to compounds of the formula STR1 wherein R1 is an acyl group derived from a carboxylic acid, hydrogen, or an amino protecting group; R2 is hydrogen, hydroxy, lower alkyl-Qp -, cycloalkyl, lowe