Stereochemistry and chiroptical properties of the nonplanar nitrosamine group in N-nitrosoaziridines

(S)-N-Nitrosoazetidine-2-carboxylic acid

“…Since the molecular geometry of these compounds critically in¯uences their biological activity, the stereochemistry of N-nitrosamines has been studied using various experimental techniques (Poøon  ski et al, 1996, and references therein). Particularly, non-planarity and, connected with it, inherent chirality of the N-nitrosamine chromophore strongly in¯uence the circular dichroism spectra (Shustov et al, 1992). As a correct interpretation of these spectra is assisted by a detailed knowledge of the chromophore geometry, we performed an X-ray crystallographic study of (S)-N-nitrosoazetidine-2-carboxylic acid, (I).…”

Enantioselective Inclusion Complexation ofN-Nitrosopiperidines by Steroidal Bile Acids

“…On the other hand, it is known that the nitrosamine CD is extremely sensitive to any deviations of the chromophore from planarity. [15] An inherent chirality of the twisted NNO group may exert a strong contribution to the CE, which often overweighs the contribution of the dissymmetrically placed substituents and thus governs the sign of the CE. [16] Indeed, the X-ray crystallographic data revealed small distortions of the nitrosamine group from planarity in 1-CA and 2-CA, as indicated by the corresponding torsional angles: C(2)-N-N-O 175.6 (5)8 (1-CA), 175.5(4)8 (2-CA); C(6)-N-N-O À 3.2(9)8 (1-CA), 8.3(7)8 (2-CA).…”

Stereochemistry and chiroptical properties of 1,3-dialkylaziridinones (α-lactams). Chiral rules for the nonplanar amide chromophore

“…The method used to calculate oscillator and optical rotatory MHz, in CDC13 from TMS), and optical rotation angles were deterstrengths is the same as was used previously (5,21,22) and has been mined on Autopol 111 and Polamat A polarimeters. described in detail elsewhere (23).…”