4,6,7,8,9,10-hexahydro-1H-6,10-methanopyrazino[2,3-h][3]benzazepine-2,3-dione.

Chemical structures of Varenicline Tartrate and degradant product (DP-I).........4,6,7,8,9,10-hexahydro-1H-6,10-methanopyrazino[2,3-h][3]benzazepine-2,3-dione.

(A) ¹H NMR spectrum of DP-I. (B) Proton decoupled ¹³C NMR spectrum of DP-I.


UHPLC-ToF MS⁺ of DP-I.

The impurity obtained as pale white crystals. mp 71–73. 

RP-UHPLC, tR = 1.8 min (98.5% purity).

MS (ESI, 70 eV): [M + H⁺] m/z 244. 

FT-IR (KBr), v, cm⁻¹ 3371, 3319, 3279, 3173, 3005, 2808, 1696, 1678, 1588, 1406, 1388, 1338, 1305, 1264, 1135, 1067, 873, 790, 680, 569, 485.

¹H NMR (400 MHz, DMSO-d₆ +D₂O, TMS): δ 7.2 (s, 2H, H-7,8), 3.1–3.4 (m, 6H, H-11,13,14 & 16),2.3 (m, 1H, H-12), 2.0 (d, 1H, 11.2 Hz, H-12).

¹³C NMR (100 MHz, DMSO-d₆, TMS): δ 173.8 (C-2,3), 155.1 (C-5,6), 137.6 (C-9,10), 125.1 (C-7,8), 38.8 (C-11), 37.9 (C-12), 38.8 (C-13), 45.8 (C-14), 48.6 (C-16).

UHPLC ToF MS+: m/z [M + H⁺].Calcd for C₁₃H₁₃N₃O₂: 244.1086; found: 244.1082.

Based on the above spectral data, the molecular formula of DP-I is C₁₃H₁₃N₃O₂ and the corresponding structure was characterized as 4,6,7,8,9,10-hexahydro-1H-6,10-methanopyrazino[2,3-h][3]benzazepine-2,3-dione.

PMC full text:

Sci Pharm. 2012 Apr-Jun; 80(2): 329–336. Published online 2012 Mar 20. doi:  10.3797/scipharm.1201-08

http://dx.doi.org/10.3797/scipharm.1201-08