V. Sunjic, A. Lisini, A. Sega, T. Kovac, F. Kajfez, and B. Ruscic, J. Heterocyclic Chem. 16, 757-761 (1979)

Conformation of 7-Chloro-5-phenyl-d₅-3(S)-methyldihydro-1,4-benzodiazepin-2-one in Solution

V. Šunjić,^a A. Lisini,^a,b A. Sega,^a T. Kovač,^a F. Kajfež,^a and B. Ruščić^c

^a Department of Biomedical and Biochemical Research, CRC-Chemical Research Company, San Giovanni al Natisone, Italy
^b Istituto di Chimica, Universitá degli Studi di Trieste, Trieste, Italy
^c Rugjer Bošković Institute, Zagreb, Croatia

J. Heterocyclic Chem. 16(4), 757-761 (1979)

7-Chloro-5-phenyl-d₅-3(S)-methyldihydro-1,4-benzodiazepin-2-one (1a) was synthesized by cyclocondensing N-carbobenzoxy-S-alanine with 5,2-Cl(H₂N)C₆H₃COC₆D₅, which was obtained by Grignard reaction of C₆D₅Br with 6-chloro-2-methyl-4H-3,1-benzoxazin-4-one and hydrolysis. The conformation of 1a in solution was determined using a computer-assisted LIS-NMR method. With Pr(fod)-d₂₇ as a shift reagent, it was found that a lanthanide coordinates to a carbonyl oxygen at a 2.02 Å distance (bond angle 158.07°, torsional angle 39.53°), while the substrate 1a adopts an expected quasi-boat conformation with a C(3)-methyl group exposed in a quasi-equatorial position.