. 2020 Aug 11;5(33):21094–21103. doi: 10.1021/acsomega.0c02744

Table 2. pK_a Values of Individual Nitrogen Atoms of Kanamycin B Determined Using ¹H, ¹³C, and ¹⁵N HMBC NMR Spectroscopy and Then Compared with the Published Data, as Indicated.

	individual nitrogen atoms pK_a
method	N-1	N-3	N-2′	N-6′	N-3″
¹H NMR^a	8.12	6.04		9.03	7.46
¹H NMR^b	8.16	6.71	7.35	8.93^c	7.60
¹³C NMR^b	8.10	6.80	7.40	9.10	7.70
¹⁵N HMBC NMR^b	8.05	6.85	7.35	8.90	7.65

pK_a values of individual nitrogen atoms of kanamycin A (note, which lacks an N-2′ amine) determined using ¹H NMR spectroscopy in D₂O relative to TSP at 25 °C.¹⁵ Note also that there are no literature data for the pK_a values of kanamycin B.

This work.

The pK_a value of N-6′ of kanamycin B determined using ¹H NMR spectroscopy (in this work) is the average pK_a of the values of N-6′ obtained using ¹H NMR spectroscopic data for 6′a (8.95) and 6′b (8.90).

Table 2. pKa Values of Individual Nitrogen Atoms of Kanamycin B Determined Using 1H, 13C, and 15N HMBC NMR Spectroscopy and Then Compared with the Published Data, as Indicated.

Table 2. pK_a Values of Individual Nitrogen Atoms of Kanamycin B Determined Using ¹H, ¹³C, and ¹⁵N HMBC NMR Spectroscopy and Then Compared with the Published Data, as Indicated.