(1H, q, J = 6.3 Hz, H-1Љ), 4.66 and 4.30 (1H, d, J = 7.8 Hz,
H-1β), 4.06 (3H, s, OMe), 3.89 and 3.58 (1H, dd, J = 2.4 and
12.0 Hz, H-6), 3.70 and 3.49 (1H, dd, J = 5.7 and 12.0 Hz,
H-6Ј), 3.45–3.21 (3H, m, H-2, H-3, H-4), 3.20–3.09 (1H, m,
H-5), 1.70 and 1.68 (3H, d, J = 6.3 Hz, H-2Љ). 13C-NMR for
pairs of diastereomers (75 MHz, CD3OD) δ 165.6, 142.3, 141.6,
133.4–127.8 (m, 10C), 101.9 and 101.2 (C-1β), 76.9 and 76.8,
76.7 and 76.6, 74.3 and 74.2, 71.9, 70.5 and 70.4, 61.6 and 61.3
(C-1Ј), 52.0 (OMe), 23.1 and 21.7 (C-2Ј). Electrospray HR-MS
(positive mode): m/z calcd. for C22H25N2O8 (M ϩ H)ϩ 445.1611,
found 445.1598 (100%).
(positive mode): m/z calcd. for C18H19N2O6 (M ϩ H)ϩ 359.1243,
found 359.1266 (100%).
2-(ꢁ-L-6-Deoxygalactopyranosyl)phenazine (17). 68% yield,
mp 219–220 ЊC (decomp.). Anal. HPLC (215 nm) >95%.
1H-NMR (300 MHz, CD3COOD) δ 8.38–8.30 (3H, m, H-4Ј, H-
6Ј, H-9Ј), 7.98–7.85 (3H, m, H-1Ј,H-7Ј, H-8Ј), 7.71 (1H, dd, J =
2.7 and 9.6 Hz, H-3Ј), 5.38 (1H, d, J = 7.5 Hz, H-1β), 3.94–3.85
(3H, m, H-2, H-3, H-4), 3.46 (1H, m, H-5), 1.46 (3H, d, J = 6.3
Hz, H-6). 13C-NMR (75 MHz, CD3COOD) δ 159.6, 143.8,
142.3, 141.6, 140.5, 131.8, 130.4, 129.9, 128.7, 127.6, 126.9,
107.8 (C-1Ј), 100.0 (C-1β), 76.4, 75.3, 73.8, 72.3, 17.1. Electro-
spray HR-MS (positive mode): m/z calcd. for C18H19N2O5 (M ϩ
H)ϩ 343.1294, found 343.1205 (100%).
Methyl 6-[(R/S )-1-(ꢁ-D-galactopyranosyl)ethyl]phenazine-1-
carboxylic ester (13). 97% yield, pure β, 1 : 1 mixture of
diastereomers (β-glycosides of both enantiomers of saphenic
acid), mp 210–211 ЊC. Anal. HPLC (215 nm) >95%. 1H-NMR
for pairs of diastereomers (300 MHz, CD3OD) δ 8.42 and 8.40
(1H, dd, J = 1.5 and 4.2 Hz, H-4Ј), 8.30–8.17 (3H, m, H-2Ј, H-
9Ј, H-7Ј), 7.98–7.90 (2H, m, H-3Ј and H-8Ј), 6.41 and 6.28 (1H,
q, J = 6.9 Hz, H-1Љ), 4.61 and 4.25 (1H, d, J = 7.8 Hz, H-1β),
4.07 (3H, s, OMe), 3.82–3.32 (6H, m, H-2, H-3, H-4, H-5, H-6,
H-6Ј), 1.70 and 1.68 (3H, d, J = 6.3 Hz, H-2Љ). 13C-NMR (75
MHz, CD3OD) δ 167.6, 143.4, 141.8, 133.5, 133.4, 132.0, 131.5,
131.4, 129.3, 129.2, 128.5, 128.2, 126.2, 101.8 (C-1β), 75.4 and
75.3, 73.9 and 73.8, 72.0 and 71.7, 71.6 and 70.3, 69.1 and 69.0,
61.3 and 60.9 (C-1Ј), 52.0 (OMe), 23.2 and 21.8 (C-2Ј). Electro-
spray HR-MS (positive mode): m/z calcd. for C22H25N2O8
(M ϩ H)ϩ 445.1611, found 445.1613 (100%).
General procedure for the methyl ester hydrolysis
The methyl ester (12, 13 or 14) and LiOHؒH2O (5 equiv.) were
dissolved in MeOH–H2O (3 : 1) and stirred at room temper-
ature for 19 h. The reaction mixture was acidified to pH 4 with
HCl (aq. 4 M), evaporated to dryness, and purified by column
chromatography on a Biotage QUAD3ϩ (eluting with CH2Cl2–
MeOH 85 : 15 or 90 : 10) to give the free acids 18–20.
6-[(R/S )-1-(ꢁ-D-Glucopyranosyl)ethyl]phenazine-1-carboxylic
acid (18). Quant. yield, 1 : 1 mixture of diastereomers (β-
glycosides of both enantiomers of saphenic acid), oil. Anal.
1
HPLC (215 nm) >95%. H-NMR (300 MHz, CD3OD) δ 8.66
(1H, br d, J = 6.9 Hz, H-2Ј), 8.45 (1H, br d, J = 8.7 Hz, H-4Ј),
8.34 and 8.23 (1H, d, J = 6.9 Hz, H-9Ј), 8.14–7.97 (3H, m, H-3Ј,
H-7Ј,H-8Ј), 6.38 and 6.24 (1H, q, J = 6.3 Hz, H-1Љ), 4.70 and
4.35 (1H, d, J = 7.2 Hz, H-1β), 3.90 and 3.61 (1H, dd, J = 2.4
and 12.0 Hz, H-6), 3.73 and 3.50 (1H, dd, J = 5.4 and 12.0 Hz,
H-6Ј), 3.49–3.27 (3H, m, H-2, H-3, H-4), 3.20 (1H, m, H-5),
1.70 and 1.69 (3H, d, J = 6.3 Hz, H-2Љ). 13C-NMR for pairs
of diastereomers (75 MHz, CD3OD) δ 174.7, 143.6, 142.7,
140.6, 140.1, 136.1, 134.9, 133.3, 130.1, 128.7, 128.4, 126.9,
126.6, 101.9 and 101.2 (C-1β), 76.9 and 76.8, 76.7 and 76.6,
74.3 and 74.2, 71.8, 70.5 and 70.4, 61.6 and 61.4 (C-1Ј), 23.2
and 21.8 (C-2Ј). Electrospray HR-MS (positive mode): m/z
calcd. for C21H23N2O8 (M ϩ H)ϩ 431.1454, found 431.1453
(100%).
Methyl 6-[(R/S )-1-(6-deoxy-ꢁ-L-glucopyranosyl)ethyl]phen-
azine-1-carboxylic ester (14). 85% yield, pure β, 1 : 1 mixture of
diastereomers (β-glycosides of both enantiomers of saphenic
acid), mp 182–183 ЊC. Anal. HPLC (215 nm) >95%. 1H-NMR
for pairs of diastereomers (300 MHz, CDCl3) δ 8.30 and 8.26
(1H, d, J = 7.2 Hz, H-4Ј), 8.16–8.10 (2H, m, H-9Ј, H-7Ј), 7.97–
7.91 (1H, d, J = 7.8 Hz, H-2Ј), 7.77–7.69 (2H, m, H-3Ј, H-8Ј),
6.13 (1H, m, H-1Љ), 4.57 and 4.37 (1H, d, J = 9.8 Hz, H-1β), 4.01
(3H, s, OMe), 3.50–3.08 (4H, m, H-2, H-3, H-4, H-5), 1.67 and
1.60 (3H, d, J = 7.2 Hz, H-2Љ), 1.25 (3H, d, J = 2.4 Hz, H-6).
13C-NMR for pairs of diastereomers (75 MHz, CDCl3) δ 167.2,
143.9, 142.0, 141.9, 140.9, 140.8, 139.0, 133.7, 131.4, 130.2,
130.1, 129.3, 128.3, 89.2 (C-1β), 75.5, 75.4, 72.2, 72.1, 60.6
(C-1Ј), 52.9 (OMe), 22.8 (C-2Ј), 17.9 (C-6). Electrospray HR-
MS (positive mode): m/z calcd. for C22H25N2O7 (M ϩ H)ϩ
429.1662, found 429.1670 (100%).
6-[(R/S )-1-(ꢁ-D-Galactopyranosyl)ethyl]phenazine-1-carb-
oxylic acid (19). 97% yield, 1 : 1 mixture of diastereomers
(β-glycosides of both enantiomers of saphenic acid), oil. Anal.
1
HPLC (215 nm) >95%. H-NMR for pairs of diastereomers
2-(ꢁ-D-Glucopyranosyl)phenazine (15). 95% yield, mp 236–
237 ЊC (decomp.). Anal. HPLC (215 nm) >95%. 1H-NMR (500
MHz, CD3COOD) δ 8.33–8.26 (3H, 3d, J = 7–8 Hz, H-4Ј, H-6Ј,
H-9Ј), 7.95 (1H, br s, H-1Ј), 7.91 (1H, br t, J = 6.8 Hz, H-7Ј/8Ј),
7.86 (1H, br t, J = 6.8 Hz, H-7Ј/8Ј), 7.69 (1H, br d, J = 7.8 Hz,
H-3Ј), 5.41 (1H, d, J = 7.5 Hz, H-1β), 4.10 (1H, br d, J = 12.4
Hz, H-6), 3.98 (1H, dd, J = 3.0 and 12.4 Hz, H-6Ј), 3.93–3–77
(4H, m, H-2, H-3, H-4, H-5). 13C-NMR (75 MHz, CD3COOD)
δ 160.3, 144.8, 143.4, 142.5, 141.4, 130.9, 130.8, 129.5, 129.4,
128.5, 128.2, 109.0 (C-1Ј), 100.9 (C-1β), 86.4, 77.2, 77.1, 74.4,
70.6. Electrospray HR-MS (positive mode): m/z calcd. for
C18H19N2O6 (M ϩ H)ϩ 359.1243, found 359.1232 (100%).
(300 MHz, CD3OD) δ 8.55–8.18 (4H, m, H-2Ј, H-4Ј, H-9Ј,
H-3Ј), 8.10–7.91 (2H, m, H-7Ј,H-8Ј), 6.41 and 6.28 (1H, q,
J = 6.1 Hz, H-1Љ), 4.62 and 4.65 (1H, d, J = 7.2 Hz, H-1β), 3.90–
3.18 (6H, m, H-6, H-6Ј, H-2, H-3, H-4, H-5), 1.71 and 1.69 (3H,
d, J = 6.3 Hz, H-2Љ). 13C-NMR for pairs of diastereomers (75
MHz, CD3OD) δ 172.1, 143.3, 142.1, 141.7, 140.7, 138.5, 137.8,
134.8, 131.1, 130.1, 128.1, 127.9, 127.1, 102.8 and 101.8 (C-1β),
75.4 and 75.3, 73.9 and 73.8, 71.7 and 71.6, 70.6, 69.1 and 68.9,
61.2 and 60.8 (C-1Ј), 23.2 and 21.8 (C-2Ј). Electrospray HR-MS
(positive mode): m/z calcd. for C21H23N2O8 (M ϩ H)ϩ 431.1454,
found 431.1443 (100%).
6-[(R/S )-1-(6-Deoxy-ꢁ-D-glucopyranosyl)ethyl]phenazine-1-
carboxylic acid (20). Quant. yield, 1 : 1 mixture of diastereo-
mers (β-glycosides of both enantiomers of saphenic acid), mp
2-(ꢁ-D-Galactopyranosyl)phenazine (16). 74% yield, mp 230–
231 ЊC (decomp.). Anal. HPLC (215 nm) >95%. 1H-NMR (500
MHz, CD3COOD) δ 8.36–8.29 (3H, 3d, J = 7–8 Hz, H-4Ј, H-6Ј,
H-9Ј), 8.01 (1H, br s, H-1Ј), 7.93 (1H, br t, J = 7.9 Hz, H-7Ј/8Ј),
7.89 (1H, br t, J = 7.5 Hz, H-7Ј/8Ј), 7.73 (1H, br d, J = 8.0 Hz,
H-3Ј), 5.37 (1H, d, J = 7.5 Hz, H-1β), 4.23–4.08 (3H, m, H-6,
H-6Ј, H-2), 4.03–3.95 (2H, m, H-3, H-4), 3.79 (1H, m, H-5).
13C-NMR (75 MHz, CD3COOD) δ 159.6, 145.1, 144.3, 143.9,
143.0, 141.0, 140.8, 136.7, 133.8, 133.5, 131.8, 108.9 (C-1Ј),
100.0 (C-1β), 83.9, 80.9, 77.9, 71.4, 63.4. Electrospray HR-MS
1
131–133 ЊC. Anal. HPLC (215 nm) >95%. H-NMR for pairs
of diastereomers (300 MHz, CD3OD) δ 8.80 (1H, br d, H-2Ј),
8.56 and 8.52 (1H, br d, H-4Ј), 8.34 and 8.20 (1H, d, J = 7.2 Hz,
H-9Ј), 8.22–8.00 (3H, m, H-3Ј, H-7Ј, H-8Ј), 6.31 and 6.21 (1H,
q, J = 6.3 Hz, H-1Ј), 4.62 and 4.28 (1H, d, J = 7.2 Hz, H-1β),
3.40–2.28 (4H, m, H-2, H-3, H-4, H-5), 1.70 and 1.68 (3H, d,
J = 6 Hz, H-2Љ), 1.29 and 0.92 (3H, d, J = 6 Hz, H-6). 13C-NMR
for pairs of diastereomers (75 MHz, CD3OD) δ 167.0, 143.9,
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 3 1 4 7 – 3 1 5 3
3152