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CHEMISTRY & BIODIVERSITY – Vol. 11 (2014)
Frs. 6.1–6.16. Fr. 6.4 was purified by CC (Sephadex LH-20; MeOH) to afford five subfractions,
Frs. 6.4.1–6.4.5. Fr. 6.4.1 was separated by CC (ODS; MeOH/H2O 80 :20), and then further purified by
CC (SiO2; petroleum ether/AcOEt 5 :3) to furnish 5 (46.0 mg) and 6 (22.0 mg). Fr. 6.4.3 was separated by
CC (ODS; MeOH/H2O 40 :60) to give 3 (350 mg) and 10 (9.5 mg). Fr. 7 (1.03 g) was submitted to CC
(Sephadex LH-20, MeOH) to afford eleven fractions, Frs. 7.1–7.11. Fr. 7.4 was subjected to CC (ODS;
MeOH/H2O 40 :60), and then further purified by CC (SiO2; CH2Cl2/MeOH 40 :1) to yield 4 (80 mg).
Ethyl Homononactate (¼ Ethyl (2S)-2-{(2S,5R)-Tetrahydro-5-[(2R)-2-hydroxybutyl]furan-2-yl}pro-
panoate; 1): Colorless oil. [a]2D0 ¼ þ28.9 (c¼0.95, MeOH). IR (KBr): 3329, 2926, 2854, 1739, 1454,
1260, 1093, 1029. 1H- and 13C-NMR: see Table 2. ESI-MS: 267 ([MþNa]þ ), 511 ([2MþNa]þ ), 245
([MþH]þ ). HR-ESI-MS: 267.1562 ([MþNa]þ , C13H24NaOþ4 ; calc. 267.1572).
Ethyl Nonactate (¼ Ethyl (2S)-2-{(2S,5R)-Tetrahydro-5-[(2R)-2-hydroxypropyl]furan-2-yl}propa-
noate; 2): Colorless oil. [a]2D0 ¼ þ9.2 (c¼0.55, MeOH). IR (KBr): 3449, 2972, 2935, 1735, 1461, 1376,
1191, 1092, 1060. 1H- and 13C-NMR: see Table 2. ESI-MS: 231 ([MþH]þ ), 253 ([MþNa]þ ), 483 ([2Mþ
Na]þ ), 269 ([MþK]þ ). HR-ESI-MS: 253.1418 ([MþNa]þ , C12H22NaOþ4 ; calc. 253.1410).
Homononactyl Nonactate (¼ rac-(2R)-2-{(2R,5S)-Tetrahydro-5-[(2S)-2-{[(2S)-2-{(2S,5R)-tetrahy-
dro-5-[(2R)-2-hydroxypropyl]furan-2-yl}propanoyl]oxy}butyl]furan-2-yl}propanoic Acid; 5): Colorless
oil. [a]2D0 ¼ ꢀ7.63 (c¼3.10, MeOH). 1H- and 13C-NMR: see Tables 3 and 4. ESI-MS: 401 ([MþH]þ ), 418
([MþNH4]þ ), 423 ([MþNa]þ ), 818 ([2MþNH4]þ ), 823 ([MþNa]þ ), 399 ([MꢀH]ꢀ ), 799 ([2Mꢀ
H]ꢀ ).
Homononactyl Homononactate (¼ rac-(2R)-2-{(2R,5S)-Tetrahydro-5-[(2S)-2-{[(2S)-2-{(2S,5R)-5-
[(2R)-tetrahydro-2-hydroxybutyl]furan-2-yl}propanoyl]oxy}butyl]furan-2-yl}propanoic Acid; 6): Color-
1
less oil. [a]2D0 ¼0 (c¼0.80, MeOH). IR (KBr): 3422, 2968, 2936, 1729, 1462, 1383, 1197, 1064. H- and
13C-NMR: see Tables 3 and 4. ESI-MS: 415 ([MþH]þ ), 437 ([MþNa]þ ), 413 ([MꢀH]ꢀ ). HR-ESI-MS
413.2537 ([MꢀH]ꢀ , C22H37Oꢀ7 ; calc. 413.2539).
Ethyl Homononactyl Nonactate (¼(2S)-1-{(2S,5R)-5-[(2R)-1-Ethoxy-1-oxopropan-2-yl]tetrahydro-
furan-2-yl}butan-2-yl (2S)-2-{(2S,5R)-Tetrahydro-5-[(2R)-2-hydroxypropyl]furan-2-yl}propanoate; 7):
Colorless oil. [a]2D0 ¼ ꢀ12.53 (c¼0.76, MeOH). IR (KBr): 3461, 2971, 2937, 1733, 1460, 1377, 1191,
1
1091, 1062. H- and 13C-NMR: see Tables 3 and 4. ESI-MS: 429 ([MþH]þ ), 446 ([MþNH4]þ ), 451
([MþNa]þ ), 874 ([2MþNH4]þ ). HR-ESI-MS: 451.2680 ([MþNa]þ , C23H40NaOþ7 ; calc. 451.2672).
Ethyl Homononactyl Homononactate (¼(2S)-1-{(2S,5R)-5-[(2R)-1-Ethoxy-1-oxopropan-2-yl]tetra-
hydrofuran-2-yl}butan-2-yl (2S)-2-{(2S,5R)-Tetrahydro-5-[(2R)-2-hydroxybutyl]furan-2-yl}propanoate;
8): Colorless oil. [a]2D0 ¼0 (c¼0.25, MeOH). IR (KBr): 3449, 2969, 2932, 1732, 1459, 1388, 1193, 1066. 1H-
and 13C-NMR: see Tables 3 and 4. ESI-MS: 443 ([MþH]þ ), 460 ([MþNH4]þ ), 465 ([MþNa]þ ). HR-
ESI-MS: 465.2831 ([MþNa]þ , C24H42NaO7þ ; calc. 465.2823).
Ethyl Nonactyl Nonactate (¼(2S)-1-{(2S,5R)-5-[(2R)-1-Ethoxy-1-oxopropan-2-yl]tetrahydrofuran-
2-yl}propan-2-yl (2S)-2-{(2S,5R)-Tetrahydro-5-[(2R)-2-hydroxypropyl]furan-2-yl}propanoate; 9): Col-
orless oil. [a]2D0 ¼0 (c¼0.15, MeOH). IR (KBr): 3448, 2973, 1734, 1459, 1377, 1192, 1090, 1059. 1H- and
13C-NMR: see Tables 3 and 4. ESI-MS: 415 ([MþH]þ ), 437 ([MþNa]þ ). HR-ESI-MS: 415.2702 ([Mþ
H]þ , C22H39Oþ7 ; calc. 415.2696).
Bishomononactic Acid (¼ rac-(2S)-2-{(2S,5R)-Tetrahydro-5-[(2S)-2-hydroxy-3-methylbutyl]furan-
1
2-yl}propanoic Acid; 10): Colorless oil. H-NMR (300 MHz, CD3OD): 3.96–4.00 (m, 1 H); 3.86–3.90
(m, 1 H); 3.39–3.45 (m, 1 H); 2.32–2.37 (m, 1 H); 1.87–1.96 (m, 2 H); 1.36–1.65 (m, 5 H); 1.01 (d, J¼
6.9, 3 H); 0.80 (d, J¼7.2, 6 H). 13C-NMR (75 MHz, CD3OD): 181.6; 82.0; 78.0; 74.6; 47.1; 42.3; 35.3; 32.5;
29.6; 19.2; 17.9; 14.0. ESI-MS: 253 ([MþNa]þ ), 229 ([MꢀH]ꢀ , 459 ([2MꢀH]ꢀ ). The spectral
properties were identical to those reported in [6].
Synthesis of 3a and 3b. Homononactic acid (3; 18 mg) and l-phenylalanine methyl ester (25 mg)
were dissolved in 5 ml of CH2Cl2, then 25 mg of N,N’-dicyclohexylcarbodiimide (DCC) and 16 mg of 4-
(dimethylamino)pyridine (DMAP) were added, and the mixture was stirred at r.t. for 48 h for the
preparation of homonoactic amide derivatives. Completion of the reaction was monitored by TLC. HCl
(1n, 10 ml) was added with vigorous stirring to quench the reaction. The org. layer was separated, and the
aq. layer was extracted with CH2Cl2 (2ꢁ10 ml). The combined org. extracts were washed with brine
(30 ml) and dried (Na2SO4). After filtration and evaporation in vacuo, the residue was purified by prep.