The mass spectrum of 5 at high mass numbers exhibits a peak for the molecular ion with m/z 624 and several peaks
formed from loss of several waters and benzoic acid: m/z 642 [M + NH ], 625 [MH], 607 [MH - H O], 589 [MH - 2H O], 571
4
2
2
[MH - 3H O], 520 [M + NH - C H O ], 503, 502, 485, 467.
2
4
7 6 2
According to IR, mass, and PMR spectra, 5 was identified as 20-hydroxyecdysone-2,3-monoacetonide-22-benzoate,
which was synthesized previously from 20-hydroxyecdysone-22-benzoate [1].
Hydrolysis of 5 with dilute acetic acid produced 6, the IR spectrum of which had absorption bands at 1710 and 1285
-1
(ester) and 1610, 1587, and 720 cm (benzene ring). This is also consistent with signals for five aromatic protons in the PMR
spectrum (Table 1).
Taken together, the results indicate that the benzoic acid is bonded to the C-22 hydroxyl.
Thus, 6 is 20-hydroxyecdysone-22-benzoate. This compound was synthesized for the first time [1].
EXPERIMENTAL
PMR spectra were recorded on a Bruker WM 250 MHz instrument in CD OD using TSP-d as a standard; IR spectra,
3
4
on a Perkin—Elmer System 2000 FTIR Fourier-spectrometer in KBr disks; mass spectra, on a JEOLJMS-700 instrument using
ammonia as the reactive gas.
The following solvent systems were used for chromatography: CHCl :CH OH (25:1, 1; 50:1, 2; 9:1, 3).
3
3
2,3;20,22-Diacetonide-20-hydroxyecdysone (2). Asuspension of1(1.2g)in anhydrousacetone(170mL)wastreated
with phosphomolybdic acid (24 mg), shaken at room temperature until 1 had completely dissolved, concentrated in vacuum to
a small volume, diluted with water, and neutralized with NaHCO solution. The neutral solution was extracted with
3
ethylacetate. The extract was chromatographed over a silica-gel column. Elution using system 1 afforded 2 (0.95 g, 70%),
20
-1
C H O , mp 230-232°C (ether:acetone), [α]
+36.8 ± 2° (c 0.30, CH OH). IR spectrum (KBr, ν, cm ): 3460 (OH), 1670
3
33 52
7
D
(7-en-6-ketone). Mass spectrum (m/z): 578 [M + NH ], 561 [MH], 543 [MH - H O], 538 [M + NH - C H O], 521 [MH -
4
2
4
2 6
C H O], 503 [MH - C H O - H O], 480, 447, 445, 380, 364, 304, 279, 234, 193, 160, 132, 78.
2
6
2
6
2
20-Hydroxyecdysone-2,3-monoacetonide (3) and 20-Hydroxycdysone-20,22-monoaceonide (4). Compound 2
(0.9 g) was hydrolyzed with acetic acid (70 mL) in aqueous CH OH (12:19) at room temperature for 4 h. The reaction mixture
3
was diluted with water and neutralized with NaHCO solution. The neutral solution was extracted with ethylacetate. The
3
extract was chromatographed over a column usingsystem 2 toafford 3 (135 mg, 15%), C H O , mp 242-244°C (ethylacetate),
30 48
7
20
[α]
+59.2 ± 2° (c 0.32, CH OH). UV spectrum (EtOH, λ , nm): 246 nm (log ε 4.00).
IR spectrum (KBr, ν, cm ): 3400-3450 (OH), 1650 (7-en-6-ketone). Mass spectrum (m/z): 538 [M + NH ], 521 [MH],
D
3
max
-1
4
503 [MH - H O], 485 [MH - 2H O], 467 [MH - 3H O], 404, 387, 330, 318, 279, 232, 186, 156, 130, 101, 99, 84.
2
2
2
Further elution of the column using system 2 afforded 4 (155 mg, 17%) [9]. Mass spectrum (m/z): 505, 502, 487, 469,
462, 445, 429, 427, 411, 409, 363, 345, 329, 327, 301, 300, 201, 161, 143, 125, 102, 99, 81.
20-Hydroxyecdysone-2,3-monoacetonide-22-benzoate (5). Compound 3 (125 mg) was dissolved in dry pyridine
(20 mL) and benzoylated with benzoyl chloride (3 mL) at room temperature for 24 h. After solvent was removed, the solid was
chromatographed over a silica-gel column with elution using system 2 to afford 5 (55 mg, 37%), C H O , mp 242-244°C
37 52
8
(CHCl ). Mass spectrum (m/z): 642 [M + NH ], 625 [MH], 607, 589, 571, 520, 503, 502, 485, 467, 420, 409, 362, 282, 247,
3
4
203, 163, 99, 78.
20-Hydroxyecdysone-22-benzoate (6). Compound 5 (45 mg) was hydrolyzed with acetic acid (6 mL) in aqueous
CH OH (2.6 mL) at room temperature for 3 h. The reaction mixture was worked up as described above. Chromatography over
3
a column using system 3 afforded 6 (24 mg, 56%) [1], C H O , mp 202-205°C. Mass spectrum (m/z): 602 [M + NH ], 585
34 48
8
4
[MH], 567 [MH - H O], 549 [MH - 2H O], 531 [MH - 3H O], 520 [M + NH - C H O ], 502, 486, 467, 445, 444, 427, 409,
2
2
2
4
7 6 2
353, 346, 282, 247, 240, 166, 140, 105, 99, 78.
REFERENCES
1.
2.
Z. Saatov, M. B. Gorovits, N. K. Melibaev, and N. K. Abubakirov, Khim. Prir. Soedin., 77 (1986).
N. Sh. Ramazanov, E. S. Maksimov, Z. Saatov, and N. D. Abdullaev, Khim. Prir. Soedin., 59 (1996).
490