Delcorinine, a new alkaloid from Delphinium corymbosum

Article abstract of DOI:10.1023/A:1012582410576

The aerial part of D. corymbosum yielded delcoridine and a new C₁₉-norditerpenoid alkaloid delcorinine. The structure of delcorinine was established using spectral data and correlation with delcorine and delsoline.

Full text of DOI:10.1023/A:1012582410576

Chemistry of Natural Compounds, Vol. 37, No. 3, 2001
DELCORININE, A NEW ALKALOID FROM
B. T. Salimov
Delphinium corymbosum
UDC 547.944/945
The aerial part of D. corymbosum yielded delcoridine and a new C19-norditerpenoid alkaloid delcorinine.
The structure of delcorinine was established using spectral data and correlation with delcorine and delsoline.
Key words:
Delphinium corymbosum, new C19-norditerpenoid alkaloid delcorinine.
Separation of the total alkaloids (CHCl ) of the aerial part of D. corymbosum collected during flowering near
3
1
Pokatilovka (Republic of Kazakhstan, Dzhungarskii Alatau) [1] yielded delcoridine and a new base C24H37NO7 ( ), mp 226-
-1
o
1
228 C (acetone), called delcorinine. The IR spectrum of contains absorption bands at 3470, 3330 (OH), and 1090 cm (C–O
ether). The PMR spectrum exhibits signals for N-ethyl (1.07, t, J = 7.0 Hz, 3H), two methoxyls (3.31 and 3.33, s, 3H each),
+
1
and methylenedioxy group (5.07 and 5.12, s, 1H each). The mass spectrum of gives peaks with m/z 451 [M (46)], 436 (33),
434 (100), 421 (87), 406 (33), 404 (25), 395 (17), 392 (50), 390 (25), 378 (19), 376 (25), 374 (8), 364 (19), 362 (17), 360 (8),
332 (4).
1
The composition and spectral data indicate that is a C19-norditerpenoid alkaloid with the lycoctonine skeleton and
the following structural formula: C19H21(N–C2H5)(OH)3(OCH3)2(–O–CH2–O–).
1
2
A comparison of the structural formulas of and delcorine ( ) [3] (four methoxyls and one hydroxyl) indicates that
they differ in the number of methoxyls and hydroxyls whereas the total number of these substituents is the same. Methylation
+
1
3
4
of by methyliodide in dioxane in the presence of NaH gave the dimethyl ether , M 479, and 6-O-methyldelcorine ( ) [4].
3
5
Reaction of with H SO (10%) afforded the known alkaloid delsoline ( ) [5]. The correlation confirms the presence of the
2
4
1
lycoctonine skeleton in and reveals the position and configuration of the substituents, indicating a OH on C-1 and
methylenedioxy group on C-7 and C-8. The relative position of the remaining substituents was solved as follows.
OR
OCH
2
3
16
OR
OH
N
17 12
OCH
OCH
14
8
3
3
15
1
N
4
11
6
O
OH
OH
O
18
19
OR
OCH
1
3
H CO
H CO
3
3
5
1: R = R = R = H
1
2
2: R = R = CH ; R = H
2
3
1
3: R = H; R = R = CH
1
2
3
4: R =R = R = CH
1
2
3
6: R = R = R = COCH
1
2
3
1
6
6
Acetylation of by acetic anhydride in pyridine gave the triacetyl derivative . The PMR spectrum of has a 1H
singlet at 5.42. This signal for 1 appears at 4.32, which is characteristic for H-6 [6], and places the second hydroxyl on
C-6. Furthermore, a 1H triplet with J = 5.0 Hz for H-14 appears at 3.66 in the PMR spectrum of 6 [7], which indicates that
one of the methoxyls occurs on C-14.
+
+
The mass spectrum of 1 contains peaks for [M - 56] and [M - 87] , which is due to the locations of the -hydroxyl
S. Yu. Yunusov Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan,
Tashkent, fax (99871) 120 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 231-232, May-June, 2001.
Original article submitted June 4, 2001.
0009-3130/01/3703-0272$25.00 ©2001 Plenum Publishing Corporation
272

and methoxyl at the 1- and 18-positions, respectively [8]. Therefore, the 16-position is the only one possible for the third
hydroxyl. Thus, delcorinine has structure 1.
A characteristic feature of the mass spectra of C(6)-methoxy and C(7)-C(8)-methylenedioxy lycoctonine compounds
+
is the presence of a peak for [M - 45] , which is due to loss of methyl from C(6)-OCH and formaldehyde from methylenedioxy
3
+
group [9]. Transformation from 4 to 3 sharply increases the strength of the [M - 45] peak whereas that of the peak caused by
loss of substituent from C-1 decreases significantly. This indicates that the hydroxyl on C-1 in lycoctonine compounds that have
+
C(6)-methoxy and C(7)-C(8)-methylenedioxy groups enhances formation of [M - 45] ions.
EXPERIMENTAL
The purity of the compounds was checked by TLC on KSK silica gel using C H —CH OH (4:1), CHCl —CH OH
6
6
3
3
3
(20:1, 9:1, 4:1), and CHCl —C H OH (9:1), and on aluminum oxide using CHCl , CHCl —CH OH (50:1), and ether—hexane
3
2
5
3
3
3
(3:1). IR spectra were recorded on a UR-20 instrument in KBr pellets; PMR spectra, on a JNM-4H-100/100 MHz spectrometer
in CDCl with HMDS internal standard; mass spectra, in an MX-1310 instrument equipped with a direct probe into the ion
3
source.
Isolation of Delcorinine (1) and Delcoridine. The total alkaloids (CHCl ) [1] were chromatographed over a column
3
of deactivated Al O (1:10) (CHCl eluent, 300 mL fraction volume). Fractions 1-15 (8.4 g) were rechromatographed on a
2
3
3
column of deactivated Al O (1:30) [CHCl eluent, fractions 1-45; CHCl —CH OH (100:1), fractions 46-105; fraction volume
2
3
3
3
3
200 mL]. Acidification of the alcoholic solution of fractions 9-12 by alcoholic HClO (10%) gave delcoridine perchlorate
4
(0.15 g). Fractions 51-59 afforded delcorinine (0.29 g) upon treatment with acetone.
Triacetyldelcorinine (6). A mixture of 1 (0.05 g), acetic anhydride (5.0 mL), and pyridine (0.5 mL) was left at room
+
temperature for 4 d. Usual work up gave 6 (0.056 g), M 577. PMR spectrum: 2.0 (9H, 3×COCH ).
3
Methylation of 1. A mixture of 1 (0.078 g) in dioxane (20.0 mL), CH I (2.0 mL), and NaH (0.02 g) was boiled and
3
stirred for 16 h. The NaH was removed. The filtrate was evaporated to dryness. The solid was dissolved in H SO (5%),
2
4
washed with ether, basicified with soda, and shaken with CHCl . The CHCl extracts were dried over Na SO and evaporated.
3
3
2
4
The solid (0.082 g) was chromatographed over a column of deactivated Al O (1:20) [eluent: hexane—ether (3:1), fraction
2
3
+
volume 1.0 mL]. Fractions 17-24 gave 6-O-methyldelcorine (0.012 g), mass spectrum, m/z: 493 M (13), 478 (24), 463 (23),
462 (100), 448 (67), 446 (24), 434 (11), 432 (53), 420 (24), 418 (44), 416 (40), 404 (33), 402 (49), 374 (13). Fractions 38-63
+
gave 3 (0.03 g), mass spectrum, m/z: 479 M (16), 462 (56), 449 (12), 434 (100), 432 (20), 423 (14), 420 (12), 418 (80), 406
(24), 404 (72), 402 (32), 392 (16), 390 (48), 388 (28), 360 (24).
Acid Hydrolysis of 3. A solution of 3 (0.025 g) in H SO (50.0 mL, 10%) was heated on a water bath for 10 h, cooled
2
4
to room temperature, diluted with water, and worked up as usual to give delsoline (0.01 g), mp 205-211oC (acetone).
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1.
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5.
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