33866-63-6

Upstream product

• 1144516-35-7 BrH*C₁₃H₁₅NO₂S 
• 676438-30-5 [(4,5-dihydro-3H-pyrrol-2-ylsulfanyl)]-phenyl-acetic acid methyl ester 
• 2295-35-4 pyrrolidin-2-thione 
• 37167-62-7 bromo-phenyl-acetic acid methyl ester 

Relevant academic research and scientific papers

The influence of the ring size of thiolactams in the Eschenmoser coupling reaction in presence of DBU. Formation of bicyclic thiazolidinones or thioimines

The different behaviors of pyrrolidin-2-thione and piperidin-2-thione under a modified Eschenmoser sulfur contraction reaction protocol using DBU as base was observed. The pyrrolidin-2-thione 1b follows the expected reaction course, leading to thioimines

Studies on the Eschenmoser coupling reaction and insights on its mechanism. Application in the synthesis of Norallosedamine and other alkaloids

The conditions of the Eschenmoser coupling reaction were studied. The formation of the α-thioiminium ion was achieved faster in the presence of an additive (NaI) and dry chloroform as the preferred solvent. The developed conditions were used for the second part of the reaction (the sulfur extrusion itself). The present protocol avoids the formation of byproducts, which were previously described as a major drawback to be overcome. Electrospray ionization tandem mass spectrometry was used to characterize some aspects (intermediates) of the first step of the reaction mechanism. Some reduction conditions were properly tested and the selected conditions were applied to the synthesis of the natural alkaloid Norallosedamine and other derivatives.