Nmr Spectral Data (Δ Ppm) of Sd8 and Reference Compound

HMBC also showed the interaction of this proton with C-6b, C-11a and C-8. With the above data analysis and comparison with published references, it was possible to identify compound SD8 as dehydrocrebanin [123] ( Figure 3.9 ).

Figure 3.9. Structure of compound SD8

3.1.2.9. Compound SD9

Compound SD9 was isolated as a white solid. The ESI-MS spectrum showed a pseudomolecular ion peak at m/z 120.8 [MH] - consistent with the molecular formula C 7 H 6 O 2 . 1 H-NMR (500 MHz, CD 3 OD) and 13 C-NMR (125 MHz, CD 3 OD) spectra:

See table 3.9 .

Table 3.9. NMR spectral data ( δ ppm) of SD9 and reference compounds

Location

a CD 3 OD, b 500 MHz, c 125 MHz

# δ C of 4-hydroxybenzaldehyde measured in CD 3 OD [125]

= 9.0 Hz, H-2, H-6) and 6.92 (2H, d, J = 9.0 Hz, H-3, H-5) characterize the aromatic ring system of AAʹBBʹ type. In addition, the proton spectrum also showed the signal of the aldehyde group at δ H 9.77 (1H, s, H-7). The 13 C-NMR and DEPT spectra showed the signals of 7 carbons, of which 6 carbons of the aromatic ring at δ C 130.0 (C-1), 133.4 (C-2, C-6), 117.0 (C-3, C-5) and 165.7 (C-4). The signal at δ C 192.7 (C-7) characterizes the aldehyde group.

With the above spectral data analysis and comparison with published references, SD9 can be identified as 4-hydroxybenzaldehyde [125] ( Figure 3.10 ).

Figure 3.10. Structure of compound SD9

3.1.2.10. Compound SD10

Compound SD10 was isolated as a white amorphous powder. The ESI-MS spectrum showed a pseudomolecular ion peak at m/z 292.9 [M+Na] + consistent with the molecular formula C13H18O6 . The 1 H-NMR (500 MHz , CD3OD ) and 13 C-NMR (125 MHz, CD3OD) spectra were obtained .

MHz, CD 3 OD): See table 3.10 .

Table 3.10. NMR spectral data ( δ ppm) of SD10 and reference compounds

Location

a CD 3 OD, b 500 MHz, c 125 MHz

# δ C of benzyl β-D-glucopyranoside measured in CD 3 OD [126]

The 1 H-NMR spectrum showed signals of 5 aromatic protons at δ H 7.41 (2H, m, H-2, H-6), 7.31 (2H, m, H-3, H-5) and 7.26 (1H, m, H-4) suggesting the presence of a substituted benzene ring at position 1. In addition, the proton spectrum also showed signals of the oxymethylene group at δ H 4.66 (1H, d, J = 12.0 Hz, H-7) and 4.92 (1H, d, J = 12.0 Hz, H-7). In addition, the presence of β -D-glucopyranosyl sugar group was also shown through the signals of anomeric protons with large coupling constants [ δ H 4.35 (1H, d, J = 8.0 Hz)], hydroxymethylene group protons [ δ H 3.69 (1H, d, J = 6.0; 12.0 Hz), 3.89 (1H, d, J = 2.5; 12.0 Hz)] and hydroxymethin group protons [ δ H 3.23 – 3.34 (4H, m)]. The 13 C-NMR spectrum showed signals of 13 carbons, of which 6 carbons of β -D-glucopyranosyl sugar group [ δ C 103.2, 75.1, 77.9, 71.6, 78.0 and 62.8]. The position of this sugar moiety was determined at C-7 through the HMBC interaction between H-1′ ( δ H 4.35) and C-7 ( δ C 71.7). With the above spectral data analysis and comparison with published references, compound SD10 can be identified as benzyl β- D-glucopyranoside [126] ( Figure 3.11 ).

Figure 3.11. Structure of compound SD10

3.1.2.11. Compound SD11

Compound SD11 was obtained as a white amorphous powder. The ESI-MS spectrum showed a pseudomolecular ion peak at m/z 409 [M+Na] + consistent with the molecular formula C19H30O8 . The 1 H-NMR ( 500 MHz , CD3OD ) and 13 C - NMR (125 MHz,

The 1 H-NMR spectrum of compound SD11 showed the signals of an olefin proton of the form C=CH at δ H 5.89 (1H, br s, H-4) and a doubly different double bond (CH=CH) of the trans form at δ H 6.99 (1H, d, J = 15.5 Hz, H-7) and 5.75 (1H, dd, J = 15.5 Hz, H-8); 3 tertiary methyl groups [ δ H 1.03 (3H, s, H-12), 1.06 (3H, s, H-11) and 1.96 (3H,

The 13 C-NMR and HSQC spectra of compound SD11 showed resonance signals of 19 carbons, including 13 carbons characteristic of the megastigman framework: 1 carbonyl group at δ C 201.2 (C-3), 2 methine olefin groups of the double bond (CH=CH) at δ C 133.7 (C-7)/133.7 (C-8), 2 other olefin carbon signals of the double bond CH=C at 127.1 (C-4)/167.0 (C-5), 4 methyl groups at δ C 19.5 (C-13), 22.2 (C-10), 23.4 (C-11),

The 6 R , 9 S configuration was determined based on the chemical shifts of carbon at positions C-7, C-8 and C-9 ( Table 3.11 ). From the above analysis combined with comparison of NMR spectral data with the previously published compound (6 R , 9 S )-roseoside [127], it can be confirmed that SD11 is (6 R , 9 S )-roseoside ( Figure 3.12 ).