410075-01-3Relevant academic research and scientific papers
An entry to 7-amino- and to 2-ethoxycarbonyl-5-dethia-5-oxa-cephams from 1,3-alkylidene-l-erythritol
Danh, Tong Thanh,Borsuk, Katarzyna,Solecka, Jolanta,Chmielewski, Marek
, p. 10928 - 10936 (2007/10/03)
The alkoxyallene derived from 1,3-benzylidene-l-erythritol when treated with chlorosulfonyl isocyanate provided diastereomeric β-lactams with moderate stereoselectivity. After the intramolecular alkylation of the nitrogen atom, these afforded compounds ha
5-Dethia-5-oxacephams: Toward correlation of absolute configuration and chiroptical properties
Lysek, Robert,Borsuk, Katarzyna,Chmielewski, Marek,Kaluza, Zbigniew,Urbanczyk-Lipkowska, Zofia,Klimek, Agata,Frelek, Jadwiga
, p. 1472 - 1479 (2007/10/03)
The relationship between chiroptical properties of differently substituted 5-dethia-5-oxacephams and their respective molecular structures was investigated. The amide chromophore of the β-lactam unit in these compounds was found to be nonplanar with a shallow pyramidal configuration at the nitrogen atom. Due to the nonplanarity, the β-lactam system becomes inherently dissymmetric, which is supported by a high magnitude of the n → π* CD band. It was also found that the helicity of the lactam moiety in investigated oxacephams is controlled by the absolute configuration at the C(6) carbon atom. On this basis, a helicity rule correlating a positive (negative) sign of the n → π* Cotton effect with a negative (positive) O=C-N-C(6) torsional angle for policyclic β-lactam derivatives possessing a nonplanar amide chromophore was formulated.
