Table 5.

Chemical shifts of the product 6 in ¹H and ¹³C NMR spectrum of Fraction 2 obtained from the heat treatment of kojibiose under weak alkaline condition.

Sugar ring	Position	α-Furanose (29 %)					β-Furanose (71 %)
		13C	1H				13C	1H
		δ (ppm)	δ (ppm)	Shape	J (Hz)		δ (ppm)	δ (ppm)	Shape	J (Hz)
I	1	98.2	5.49	d	5.2		103.6	5.40	d	5.2
	2	80.5	4.23	t-like	5.0		84.0	4.14	t-like	5.0
	3	81.9	4.71	t-like	4.6		82.0	4.75	t-like	4.7
	4	83.8	4.64	t-like	4.6		83.1	4.78	t-like	4.8
	5	74.0	4.44a	m			74.2	4.40a	m
	6	74.1	3.99	dd	7.8, 8.6		74.4	4.06	dd	6.5, 9.0
	6′		3.93	dd	6.8, 8.6			3.64a	m
II (αGlc)	1	102.0	5.12	d	3.6		100.7	5.08	d	3.7
	2	75.7	3.57a				76.2	3.56a
	3	75.2	3.84a				74.9	3.76a
	4	72.3	3.44a				72.2	3.47a
	5	75.4	nd				75.4	3.67a
	6	65.0	nd				65.0	3.85a
	6′		nd					3.80a

The terms I and II indicate the first (3,6-anhydro-D-mannofuranose) and second (α-D-glucopyranose) residues from the reducing end, respectively. Bolds and bold italics represent HMBC correlations between the anomeric proton and carbon of α-D-glucopyranose and the carbon and proton of 3,6-anhydro-D-mannofurnose, respectively. nd, these values cannot be determined due to overlapping signals. ^a, these signals were assigned by HSQC spectrum. The ¹H and ¹³C NMR spectra were shown in Supplementary material; Figs. S5 and S6.