1072 J. Agric. Food Chem., Vol. 47, No. 3, 1999
Jacobs and Metzler
42%) of an orange gum. The product was refluxed with Raney
nickel (made of 13.6 g of nickel-aluminum alloy) in absolute
ethanol (55 mL) for 5 h to yield 625 mg of trans-3,4-bis-(3-
hydroxybenzyl)-γ-butyrolactone (ENL; quantitative yield). Af-
ter crystallization from chloroform, the purity of ENL was
>99% according to GC/MS.
(t, 7′), 38.71 (t, 7), 42.46 (d, 8), 45.75 (d, 8′), 72.32 (t, 9), 113.86
(d), 115.01 (d), 115.92 (d), 116.31 (d), 118.07 (d), 120.43 (d),
125.72 (s), 130.03 (d), 140.70 (s), 149.03 (s), 150.11 (s), 157.43
(s), 181.18 (s, 9′).
trans-3-(2,3-Dihydroxybenzyl)-2-(3-hydroxybenzyl)-γ-butyro-
lactone. Mass spectrum (EI, 70 eV) m/z (% relative abun-
dance): 530 (100, M+), 515 (25), 351 (4), 335 (16), 268 (45,
McLafferty rearrangement product), 179 (12, benzylic frag-
mentation), 73 (9). 1H NMR (MeOD) δ (ppm): 2.46-2.98 (6H,
m, 7, 7′, 8, 8′), 3.92 (1H, dd, 9A), 4.07 (1H, dd, 9B), 6.48-7.02
(7H, m). 13C NMR (MeOD) δ (ppm): 33.95 (t, 7′), 35.04 (t, 7),
42.78 (d, 8), 46.82 (d, 8′), 71.92 (t, 9), 112.88 (d), 114.63 (d),
120.15 (d), 120.34 (d), 122.40 (d), 125.35 (d), 130.46 (d), 145.00
(s), 146.37 (s), 153.02 (s), 153.44 (s), 157.21 (s), 180.36 (s, 9′).
trans-3-(3,4-Dihydroxybenzyl)-2-(3-hydroxybenzyl)-γ-butyro-
lactone. Mass spectrum (EI, 70 eV) m/z (% relative abun-
dance): 530 (85, M+), 515 (4), 293 (21), 268 (100, McLafferty
rearrangement product), 179 (16, benzylic fragmentation), 73
(31). 1H NMR (MeOD) δ (ppm): 2.24-2.70 (4H, m, 7, 8, 8′),
2.79-2,99 (2H, m, 7′), 3.87 (1H, dd, 9A), 4.06 (1H, dd, 9B),
6.37-7.14 (7H, m). 13C NMR (MeOD) δ (ppm): 35.81 (t, 7′),
38.61 (t, 7), 42.90 (d, 8), 47.54 (d, 8′), 72.84 (t, 9), 114.76 (d),
116.49 (d), 116.84 (d), 117.31 (d), 121.06 (d), 121.76 (d), 130.62
(d), 131.45 (s), 140.94 (s), 145.01 (s), 146.32 (s), 158.71 (s),
181.44 (s, 9′).
trans-3-(2,5-Dihydroxybenzyl)-2-(3-hydroxybenzyl)-γ-butyro-
lactone. Mass spectrum (EI, 70 eV) m/z (% relative abun-
dance): 530 (100, M+), 515 (5), 335 (63), 293 (7), 268 (64,
McLafferty rearrangement product), 180 (10, McLafferty re-
arrangement product), 73 (9). 1H NMR (CDCl3/MeOD) δ
(ppm): 2.55-2.95 (6H, m, 7, 7′, 8, 8′), 3.97 (1H, dd, 9B), 4.11
(1H, dd, 9A), 6.43-6.84 (6H, m), 7.10-7.14 (1H, m). 13C NMR
(CDCl3/MeOD) δ (ppm): 32.98 (t, 7′), 35.08 (t, 7), 40.54 (d, 8),
47.08 (d, 8′), 72.48 (t, 9), 114.31 (d), 114.79 (d), 116.42 (d),
116.97 (d), 117.74 (d), 121.63 (d), 126.97 (s), 130.14 (d), 139.86
(s), 148.70 (s), 150.09 (s), 157.34 (s), 180.99 (s, 9′).
For the synthesis of 2,3-bis-(3-hydroxybenzyl)-butane-1,4-
diol (END) according to Groen and Leemhuis (1980), 0.77
mmol (230 mg) of ENL dissolved in 5 mL of dry THF was
added to 5.7 mmol (216 mg) of lithium aluminum hydride in
30 mL of dry THF and stirred for 1 h at room temperature
before the mixture was refluxed for 2.5 h. The reduction gave
END in quantitative yield with a purity >99% according to
GC/MS.
The same procedure was used at a 1 mg scale for the
chemical reduction of trans-2-(2,3-dihydroxybenzyl)-3-(3-hy-
droxybenzyl)-γ-butyrolactone, trans-3-(3,4-dihydroxybenzyl)-
2-(3-hydroxybenzyl)-γ-butyrolactone, and trans-2-(2,5-dihy-
droxybenzyl)-3-(3-hydroxybenzyl)-γ-butyrolactone to obtain
2-(2,3-dihydroxybenzyl)-3-(3-hydroxybenzyl)-butane-1,4-diol,
2-(3,4-dihydroxybenzyl)-3-(3-hydroxybenzyl)-butane-1,4-diol, and
2-(2,5-dihydroxybenzyl)-3-(3-hydroxybenzyl)-butane-1,4-diol, re-
spectively.
Seven monohydroxylation products of ENL, viz., trans-2-
(2,3-dihydroxybenzyl)-3-(3-hydroxybenzyl)-γ-butyrolactone (yield
15%, purity 97%), trans-2-(3,4-dihydroxybenzyl)-3-(3-hydroxy-
benzyl)-γ-butyrolactone (yield 21%, purity 96%), trans-2-(3,5-
dihydroxybenzyl)-3-(3-hydroxybenzyl)-γ-butyrolactone (yield
15%, purity 97%), trans-2-(2,5-dihydroxybenzyl)-3-(3-hydroxy-
benzyl)-γ-butyrolactone (yield 29%, purity 98%), trans-3-(2,3-
dihydroxybenzyl)-2-(3-hydroxybenzyl)-γ-butyrolactone (yield
7%, purity 58%), trans-3-(3,4-dihydroxybenzyl)-2-(3-hydroxy-
benzyl)-γ-butyrolactone (yield 23%, purity 96%), and trans-3-
(2,5-dihydroxybenzyl)-2-(3-hydroxybenzyl)-γ-butyrolactone (yield
21%, purity 94%) were synthesized in the same manner
(Figure 1) from the respective bis(phenylthio)acetals and
benzyl bromides, which were prepared from the respective
benzylated hydroxybenzaldehydes purchased from Fluka (Dei-
senhofen, Germany), Lancaster (Mu¨hlheim, Germany), or
Aldrich (Steinheim, Germany). These and the other chemicals
used were of the highest purity available.
1
The synthesis and characterization of the materials by H
and 13C NMR spectroscopy and by GC/MS (after derivatization
with N,O-bis(trimethylsilyl)acetamide, BSA) are described in
detail elsewhere (J acobs, 1998). A brief account of the spec-
troscopic data of the monohydroxylated ENL compounds is
given below. NMR signals for ENL were assigned according
to Cooley et al. (1984); see Figure 4 for the numbering of
positions.
trans-3,4-Bis(3-hydroxybenzyl)-γ-butyrolactone (ENL). Mass
spectrum (EI, 70 eV) m/z (% relative abundance): 442 (67, M+),
263 (10), 217 (8), 205 (5), 180 (100, McLafferty rearrangement
product), 165 (6), 73 (7). 1H NMR (CDCl3/MeOD) δ (ppm):
2.40-2.65 (4H, m, 7, 8, 8′), 2.90 (1H, dd, 7′A), 3.00 (1H, dd,
7′B), 3.85 (1H, dd, 9A), 4.15 (1H, dd, 9B), 6.45-6.76 (6H, m),
7.11-7.20 (2H, m). 13C NMR (CDCl3/MeOD) δ (ppm): 35.35
(t, 7′), 38.73 (t, 7), 41.85 (d, 8), 46.94 (d, 8′), 72.20 (t, 9), 114.12
(d), 114.39 (d), 116.05 (d), 116.66 (d), 120.48 (d), 121.20 (d),
130.22 (2d), 139.85 (s), 140.36 (s), 157.72 (2s), 180.58 (s, 9′).
trans-2-(2,3-Dihydroxybenzyl)-3-(3-hydroxybenzyl)-γ-butyro-
lactone. Mass spectrum (EI, 70 eV) m/z (% relative abun-
dance): 530 (15, M+), 515 (5), 351 (100), 335 (5), 179 (12,
benzylic fragmentation), 73 (6). 1H NMR (MeOD) δ (ppm):
2.40-2.87 (6H, m, 7, 7′,8, 8′), 3.47 (1H, dd, 9A), 3.87 (1H, dd,
9B), 6.43-7.12 (7H, m).
trans-2-(3,4-Dihydroxybenzyl)-3-(3-hydroxybenzyl)-γ-butyro-
lactone. Mass spectrum (EI, 70 eV) m/z (% relative abun-
dance): 530 (100, M+), 515 (5), 267 (46, benzylic fragmenta-
tion), 205 (6), 179 (15, benzylic fragmentation), 73 (6). 1H NMR
(MeOD) δ (ppm): 2.27-2.79 (6H, m, 7, 7′, 8, 8′), 3.75 (1H, dd,
9A), 3.92 (1H, dd, 9B), 6.38-7.01 (7H, m). 13C NMR (MeOD) δ
(ppm): 39.14 (t, 7′), 39.52 (t, 7), 42.40 (d, 8), 47.74 (d, 8′), 72.75
(t, 9), 113.25 (d), 114.54 (d), 116.61 (d), 117.52 (d), 120.94 (d),
121.94 (d), 130.75 (d), 141.46 (s), 145.12 (s), 146.32 (s), 158.61
(s), 158.69 (s), 181.52 (s, 9′).
trans-2-(3,5-Dihydroxybenzyl)-3-(3-hydroxybenzyl)-γ-butyro-
lactone. Mass spectrum (EI, 70 eV) m/z (% relative abun-
dance): 530 (51, M+), 515 (8), 293 (3), 268 (100, McLafferty
rearrangement product), 253 (3), 73 (3). 1H NMR (MeOD) δ
(ppm): 2.34-2.98 (6H, m, 7, 7′, 8, 8′), 3.88 (1H, dd, 9A), 4.55
(1H, dd, 9B), 6.17-7.10 (7H, m). 13C NMR (MeOD) δ (ppm):
35.96 (t, 7′), 39.16 (t, 7), 42.70 (d, 8), 47.41 (d, 8′), 72.75 (t, 9),
102.09 (d), 108.91 (d), 108.91 (d), 114.52 (d), 116.57 (d), 120.96
(d), 130.69 (d), 140.91 (d), 141.50 (s), 141.57(s), 158.64 (s),
159.76(s), 181.35 (s, 9′).
trans-2-(2,5-Dihydroxybenzyl)-3-(3-hydroxybenzyl)-γ-butyro-
lactone. Mass spectrum (EI, 70 eV) m/z (% relative abun-
dance): 530 (71, M+), 515 (5), 351 (100), 335 (16), 267 (6,
benzylic fragmentation), 73 (6). 1H NMR (CDCl3/MeOD) δ
(ppm): 2.34 (1H, dd, 7′A), 2.61-2.82 (4H, m, 7, 8, 8′), 3.24 (1H,
dd, 7′B), 3.89 (1H, dd, 9B), 4.13 (1H, dd, 9A), 6.52-6.70 (6H,
m), 7.05-7.08 (1H, m). 13C NMR (CDCl3/MeOD) δ (ppm): 30.22
2,3-Bis(3-hydroxybenzyl)-butane-1,4-diol (END). Mass spec-
trum (EI, 70 eV) m/z (% relative abundance): 500 (27, M+
-
TMSOH), 410 (100, M+ - 2TMSOH), 231 (25), 217 (22), 205
(4), 194 (10), 180 (48, McLafferty rearrangement product), 73
(11). 1H NMR (DMSO-d6) δ (ppm): 1.90 (2H, m, 8), 2.37-2.63
(4H, m, 7), 3.37 (4H, m, 9), 6.54-6.57 (6H, m), 6.99-7.06 (2H,
m), 9.20 (2H, s). 13C NMR (DMSO-d6) δ (ppm): 33.86 (t, 7),
42.43 (d, 8), 59.99 (t, 9), 112.38 (d), 115.78 (d), 119.49 (d),
128.80 (d), 142.92 (s), 156.99 (s).
2-(2,3-Dihydroxybenzyl)-3-(3-hydroxybenzyl)-buta ne-1,4-
diol. Mass spectrum (EI, 70 eV) m/z (% relative abundance):
678 (3, M+), 588 (22, M+ - TMSOH), 498 (95, M+ - 2TMSOH),
268 (26), 231 (87), 180 (100), 73 (10).
2-(3,4-Dihydroxybenzyl)-3-(3-hydroxybenzyl)-buta ne-1,4-
diol. Mass spectrum (EI, 70 eV) m/z (% relative abundance):
678 (11, M+), 588 (72, M+ - TMSOH), 498 (70, M+
2TMSOH), 268 (90), 231 (41), 180 (100), 73 (4).
-
2-(2,5-Dihydroxybenzyl)-3-(3-hydroxybenzyl)-buta ne-1,4-
diol. Mass spectrum (EI, 70 eV) m/z (% relative abundance):
678 (41, M+), 588 (100, M+ - TMSOH), 498 (55, M+
2TMSOH), 268 (14), 231 (16), 180 (6), 73 (15).
-