The crystal and molecular structure of dl-betaprodine hydrobromide

Abstract

The crystal structure of the hydrobromide of d/-betaprodine (beta d/-1,3-dimethyl-4-phenyl-4-propionoxypiperidine) has been determined by the heavy-atom method from three-dimensional intensity data collected with a scintillation-counter diffraetometer. The structure has been refined by three cycles of differential syntheses to an R-factor of 0-10, and the hydrogen atoms of the molecule of betaprodine have been located from a three-dimensional difference synthesis. In the betaprodine molecule the piperidine ring has the chair form with the phenyl ring equatorial and the propionoxy chain axial as in the alpha isomer, but the methyl group on C(3) now is axial, instead of equatorial, and is cis to the phenyl ring on C(4).

The Molecular Conformation of 1e,2a,6e-Trimethyl-4e-phenyl-4a-acetoxypiperidine Hydrobomide in the Crystalline State

“…The bond lengths involving the hydrogen atoms are listed in Table 4. The mean C-C single bond length in the piperidine ring is 1.53 1 A and agrees well with the corresponding values found in the similar piperidine rings (7,8,10,11). The three C-N single bond lengths average 1.521 A and are rather long.…”

The crystal and molecular structure ofdl-betaprodine hydrochloride

“…'s (Ahmed & Cruickshank, 1953), and the bond angles are shown in Fig. 1 in the same diagrammatic form as by Kartha, Ahmed & Barnes (1960) and Ahmed, Barnes & Masironi (1963). The e.s.d.…”

“…The integrated intensities and background at each site were measured in the same way as for dl-betaprodine hydrobromide (Ahmed, Barnes & Masironi, 1963), and 2108 reflections (60%) were observed. The intensities were corrected by the appropriate 1/Lp factors, but no absorption corrections were considered necessary.…”

“…Crystals of dl-betaprodine (fl-dl-1,3-dimethyl-4-phenyl-4-propionoxypiperidine).hydrochloride are monoclinic, space group P21/c, as are those of the hydrochloride and hydrobromide of dl-alphaprodine, whereas dlbetaprodine hydrobromide is orthorhombic, space group Pbca (Ahmed, Barnes & Masironi, 1963). The present investigation of the crystal structure of dlbetaprodine hydrochloride was undertaken because of the importance of the configuration and conformation of the betaprodine molecule (Kartha, Ahmed & Barnes, 1960;Ahmed, Barnes & Masironi, 1963), and to be certain that no molecular changes occur when HBr is replaced by HC1 in the crystals of the hydrohalide salt.…”

“…The present investigation of the crystal structure of dlbetaprodine hydrochloride was undertaken because of the importance of the configuration and conformation of the betaprodine molecule (Kartha, Ahmed & Barnes, 1960;Ahmed, Barnes & Masironi, 1963), and to be certain that no molecular changes occur when HBr is replaced by HC1 in the crystals of the hydrohalide salt. It was also hoped that it might be possible to locate the hydrogen atom of the hydrohalide in the hydrochloride because it did not appear unequivocally in the final difference maps of the hydrobromide.…”