Assign. Shift(ppm) A 11. B 8.125 C 7.624 D 7.356 E 7.142 F 2.352 ABOVE IS PROTON NMR OF ASPIRIN AND ITS INTERPRETATION
o-acetoxybenzoic acid C9H8O4 (Mass of molecular ion: 180)
Source Temperature: 170 °C Sample Temperature: 100 °C DIRECT, 75 eV
|C9 H8 O4||0.039 g : 0.5 ml CDCl3|
ppm Int. Assign. 170.20 450 1 169.76 510 2 151.28 560 3 134.90 924 4 132.51 1000 5 126.17 986 6 124.01 974 7 122.26 397 8 20.99 674 9
CAS NO. 50-78-2, Acetylsalicylic acid H-NMR spectral analysis
CAS NO. 50-78-2, Acetylsalicylic acid C-NMR spectral analysis
H, H-COSY spectrum
In H, H-COSY spectrum are on both axes, the 1 H chemical shifts plotted; In principle, both the axes 1 to see H-NMR spectra. Thus, there is a symmetric to the diagonal diagram.
1 H-NMR spectrum of acetylsalicylic acid
H, H-COSY spectrum of acetylsalicylic acid
In the spectrum, only the range from 7.0 to 8.2 ppm is applied, because only here HH scalar couplings can be expected.
There are two types of signals:
In general it can be seen in the COSY spectrum each scalar coupling between two nuclei at four signals (two cross and two diagonal peaks) resulting connected a square; in the following example, the vicinal coupling between the H atoms is highlighted 3 and 4.
With good resolution of the COSY spectrum, the coupling constants can be determined from the fine structure of the cross and diagonal signals, but this is rarely done because of the 1-D H-NMR spectra is easily possible.DRUG APPROVALS BY DR ANTHONY MELVIN CRASTO .....FOR BLOG HOME CLICK HERE
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