4-Het(aryl)-2-pyrrolidone-3(5)-carboxylic acid alkyl(hetaryl)idenecarbohydrazides: synthesis and structure

Synthesis, structure, and biological activity of 4-hetaryl-2-pyrrolidones containing a pyrazole ring

“…Indeed, the spin-spin coupling constants of 3,4-CH methine protons ( 3 J 3-4 = 10.7–11.2 Hz) in 1 Н NMR spectra of compounds 5a – e and 4,5-CH methine protons ( 3 J 4-5 = 8.2–8.7 Hz) in the spectra of compounds 6a – g indicated their trans and cis orientation relative to the lactam ring plane. This orientation corresponded to (3 R* ,4 S* ) and (4 R *,5 R *) configurations of the chiral centers and was in good agreement with the spin-spin coupling соnstants established by us for the starting carbohydrazides 1a – e , 2a – g , 20 – 22 as well as the literature data available for trans- and cis- isomers of similar molecules. 23 – 25 …”

“…The synthesis of (3 R *,4 S *)-4-hetaryl-2-pyrrolidone-3-carbohydrazides 1a – e , (4 R *,5 R *)-4-hetaryl-2-pyrrolidone-5-carbohydrazides 2a – g , and 2-[4-aryl-2-pyrrolidon-1-yl]acetohydrazides 3a – d was accomplished by following published procedures. 20 – 22 …”

“…The starting materials 1a – e , 2a – g , and 3a – d were synthesized according to our previously developed procedures. 20 – 22 …”