performed, taking approximately 4 minutes collect. The spectral width was set at 20.0 ppm
with a 5.0 ppm centre. 13C NMR were collected at 15 MHz with a lock on the CD3OD signal;
20 480 scans with a 0.2 second delay were performed, taking approximately 16 hours to collect.
The spectral width was set at 220 ppm with 100 ppm centre. The spectra were processed using
Mestrelab’s MNova software.
Results and Discussion:
The NMR data for 1 are shown in Table 1 and the spectra are shown in Figure 2. The 1H NMR
showed 3 peaks, a triplet at = 3.66 (J = 5.4 Hz); a singlet at = 3.46 ppm; and a second triplet
at = 2.63 (J = 5.4 Hz). The relative integral ratios were 1:1:1 for each peak. These peaks are
consistent with the literature data. There were some trace impurities in the sample associated
with the manufacturing of 1. The 13C NMR spectrum also showed the 3 expected peaks from
1 (Table 1b). These also match the literature data for 1.
The NMR data for the spent scavengers were more complex, showing a mixture of products
(Figure 3). All spent scavengers showed an identical spectral profile. In the 1H NMR spectrum
there were two large multiplets (Peaks 3E and 3F) at = 3.77 – 3.45 ppm and = 3.25 – 2.82
ppm. There were 4 singlets, Peaks 3A, 3B, 3C, and 3D, at = 4.48 ppm, 4.29 ppm, 4.13 ppm,
and 3.95 ppm respectively. The expected final product, dithiazine (3), was identified by the
presence of Peaks 3A and 3C in the 1H NMR. The chemical shifts of these peaks were = 4.48
and 4.13 ppm, respectively, which is consistent with the literature values for the ring protons
on 3. These two peaks showed a relative integral ratio of 2:1, further supporting the assignment
that Peak 3A is the methylene protons between the N and S atoms on the ring, while Peak 3C
is the methylene protons between the S atoms. The presence of 3 was also supported by the 13C
NMR data, summarised in Table 2. The 13C spectrum showed a peak at = 33.0 ppm, consistent
13
with the methylene carbon between the two S atoms. Peaks 4G, 4H, and 4J in the C NMR
spectrum were also consistent with the literature values of the carbons in 3.
The reaction intermediate, thiadiazine (2), was also observed in the NMR spectra. The singlets
3B and 3D ( = 4.29 and 3.95 ppm) in the 1H NMR spectra were consistent with the literature
values for the ring protons in 2. The relative integral ratio between the two peaks was 2:1,
13
further supporting the assignment of these two peaks. The signal at = 73.7 ppm in the C
NMR is consistent with a carbon between two nitrogen atoms but was slightly lower field in
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