Nefopam methohalide

Dimethyl-l-phenyl-3,4,5,6-tetrahydro-l//-2,5-benzoxazocinium halide [nefopam methohalide] (methiodide, 19) (methobromide, 21) and (methochloride, 22)... 

A cp/mas VACP 13C-NMR study was made of these three pseudopolymorphic crystals (19, 21, and 22).29 The prefix pseudo is affixed to polymorph to describe this series of nefopam methohalide crystals since the anions therein are different. The results of this solid-state 13C-NMR study are presented in Table 3 along with the solution-state 13C chemical shifts. The cp/mas 13C-NMR spectra of crystalline 19, 21, and 22 are illustrated in Fig. 5. It is seen that the C(4) peak (<5 58.51) in the cp/mas 13C-NMR spectrum of the methochloride (22) is sharp due to the sole presence of the immobile BB conformation quaternary ammonium cation in the crystal. However, the C(4) peak (V) 59.42) in the methobromide (21) spectrum was markedly lower in intensity and broad, and in the methiodide (19) spectrum it was just a broad shoulder at 5 62.29 Therefore, as the C(4) nucleus becomes more site-disordered in the crystal due to conformational interconversion, its cp/mas peaks show lower intensities and greater line-broadening. 

Table 3. Selected solution- and solid-state cp/mas 13C-NMR spectral parameters for nefopam methohalide quaternary ammonium salts (19,21 and 22) ...

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