Abstract:Sunzmavy. From whole plants of Bulbocodtum veritum L. the flavonc luteoline (1) and the alkaloids colchicinc (11), N-form)]-l;-deacctyl-colchicine (111). 3-demethplcolchicinc (V), ( + )-bulbocodine (IX) ancl ( -)-kreysigine (XI) wcre isolatcd in crystals. The presence of 2-demcthylcolchicinc (IV), p-(VII) a n d y-lumicolchicinc (VIII), dcniecolcinc (VI) and five not identified alkaloids was demonstrated b y thin-laycr chromatography. On t h e basis of ultraviolet, infrared anti mass spectra, 1'MR.-analysis (Ov… Show more
“…Aus der Tabelle 1 ist zu ersehen, daB die Knollen des C. autumnale L. Unterschiedlich verhalt sich jedoch C. macedonicum, welches zum Unterschied von den obengenannten Arten zu Ende des Frühjahrs (Juni) blüht. Im neutralphenolischen Anteil wurden zwar die üblichen Tropolonalkaloide gefunden, der basische Anteil wies jedoch, ahnlich wie beispielsweise jener von C. vernale [21] (das ebenfalls im Die Extraktion der einzelnen getrockneten und gemahlenen Pflanzenproben erfolgte so wie in der Arbeit [12] beschrieben wurde und die Saulenchromatographie nach der in den Arbeiten [12,15,17,18,19, 221 beschriebenen Methode. Zur Dünnschichtchromatographie [12], sei es der analytischen oder der praparativen, wurden Kieselgel C und die nachstehenden Losungsmittelsysteme verwendet:…”
SUBSTANZEN V O N ARTEN DER UNTERFAMILIE WURMBAEOIDEAE U N D IHRE DERIVATE. LXXXI' Alkaloide aus Colchicum autumnale L. (T a r a) , C. latifolium S. S. und C. macedonicum KoS. jugosIawischen Ursprungs Substances of species of the subfamily Wurmbaeoideae and their derivatives. L X X X I Alkaloids o f Colchicum autumnale, C. latifolium and C. macedonicum of Yugoslavian origin2 Von O. GASIE", H. POTEXILOVA~ und F. SANTA+ A bstract From the corms, .flowers and flower stalks of the plants C o 1 c h i c u m a u t u mn a l e L. (Tara), C. l a t i f o l i u m S. S., and C. m a c e d o n i c u m Kos'. o f Yugoslavian origin there were isolated and by thin-layer chromatography demonstrated (using several solvent systems and material for comparison) the alkaloids which, together with their hRrz-values, were listed in Table 1. Zn the flowers and the flower stalks of C. 1 a t i f O 1 i u m. colchiciline and 10,ll-epoxycolchicine could also be demonstrated. The basic extract of C. m a c e d O n i c u m was not found to contain substances with a tropolone ring but the alkaloid floramultine (bechuanine). Zusammenfassung Die aus den Knollen, Bliiten und Bliitenstengeln der PfZanzen C o 1 c h i c u m a u t u m n a l e L. (Tara), C. l a t i f o l i u m S.S. und C. m a c e d o n i c u m Kos'. jugoslawischen Ursprungs isolierten oder diinnschichtchromatographisch unter Verwendung einiger Losungsmittelsysteme und Testsubstanzen nachgewiesenen Alkaloide wurden mit Angabe ihrer ~R F-W e r t e zusammengefa/3t. In den Bliiten-' LXXX. Mitteilung: Collection Czechoslov. Chem. Commun. 41 (1976). Vorlaufige Mitteilungen von Doc. Dr. O. GAXIC siehe [l]. Auf dem Gebiet von Jugoslawien wachsen C.
“…Aus der Tabelle 1 ist zu ersehen, daB die Knollen des C. autumnale L. Unterschiedlich verhalt sich jedoch C. macedonicum, welches zum Unterschied von den obengenannten Arten zu Ende des Frühjahrs (Juni) blüht. Im neutralphenolischen Anteil wurden zwar die üblichen Tropolonalkaloide gefunden, der basische Anteil wies jedoch, ahnlich wie beispielsweise jener von C. vernale [21] (das ebenfalls im Die Extraktion der einzelnen getrockneten und gemahlenen Pflanzenproben erfolgte so wie in der Arbeit [12] beschrieben wurde und die Saulenchromatographie nach der in den Arbeiten [12,15,17,18,19, 221 beschriebenen Methode. Zur Dünnschichtchromatographie [12], sei es der analytischen oder der praparativen, wurden Kieselgel C und die nachstehenden Losungsmittelsysteme verwendet:…”
SUBSTANZEN V O N ARTEN DER UNTERFAMILIE WURMBAEOIDEAE U N D IHRE DERIVATE. LXXXI' Alkaloide aus Colchicum autumnale L. (T a r a) , C. latifolium S. S. und C. macedonicum KoS. jugosIawischen Ursprungs Substances of species of the subfamily Wurmbaeoideae and their derivatives. L X X X I Alkaloids o f Colchicum autumnale, C. latifolium and C. macedonicum of Yugoslavian origin2 Von O. GASIE", H. POTEXILOVA~ und F. SANTA+ A bstract From the corms, .flowers and flower stalks of the plants C o 1 c h i c u m a u t u mn a l e L. (Tara), C. l a t i f o l i u m S. S., and C. m a c e d o n i c u m Kos'. o f Yugoslavian origin there were isolated and by thin-layer chromatography demonstrated (using several solvent systems and material for comparison) the alkaloids which, together with their hRrz-values, were listed in Table 1. Zn the flowers and the flower stalks of C. 1 a t i f O 1 i u m. colchiciline and 10,ll-epoxycolchicine could also be demonstrated. The basic extract of C. m a c e d O n i c u m was not found to contain substances with a tropolone ring but the alkaloid floramultine (bechuanine). Zusammenfassung Die aus den Knollen, Bliiten und Bliitenstengeln der PfZanzen C o 1 c h i c u m a u t u m n a l e L. (Tara), C. l a t i f o l i u m S.S. und C. m a c e d o n i c u m Kos'. jugoslawischen Ursprungs isolierten oder diinnschichtchromatographisch unter Verwendung einiger Losungsmittelsysteme und Testsubstanzen nachgewiesenen Alkaloide wurden mit Angabe ihrer ~R F-W e r t e zusammengefa/3t. In den Bliiten-' LXXX. Mitteilung: Collection Czechoslov. Chem. Commun. 41 (1976). Vorlaufige Mitteilungen von Doc. Dr. O. GAXIC siehe [l]. Auf dem Gebiet von Jugoslawien wachsen C.
“…The irradiation of colchicine leads to the formation of β- and γ-lumicolchicine (β- and γ-LCC; 3 and 4 ; Chart ). Prolonged irradiation times lead to the formation of α-lumicolchicine ( 2 ) (Chart ). − 1 The Photoisomerization of Colchicine…”
The photochemical reaction of colchicine to β- and γ-lumicolchicine, through a mechanism involving a disrotatory cyclization, is studied by theoretical methods. The energetics of the reaction, including one or two methanol solvent molecules, are studied at the DFT-B3LYP and multireference perturbation levels of theory using the 6-31G(d) basis set. The results show that, in agreement with experimental results, the first excited state of colchicine at ∼3.6 eV can lead to both β- and γ-lumicolchicine, whose energy is about 15 kcal mol(-)(1) above the colchicine energy. Owing to the high steric tension of the condensed four- and five-atom rings arising from cyclization, the two trans-lumicolchicines are higher in energy (>60 kcal mol(-)(1)), and their formation appears much less probable. A partial inclusion of the solvent effects through the addition of two solvent molecules does not alter the general conclusions based on the free energy in the gas phase. The photochemical reaction path is studied by choosing the distance between the two carbon atoms which form the new σ bond as the leading coordinate of the minimum-energy path of both the ground and the first singlet excited states. The energies are computed by Multi Configurational self-consistent-field calculations on a model molecule, retaining those atoms that presumably play an active role in the reaction. A reasonable mechanism starting from colchicine in the first singlet excited state and leading to γ-lumicolchicine is proposed. On the contrary, a high-energy transition state is found for trans-lumicolchicines, whose formation, although not strictly forbidden for energetic reasons, appears to be rather improbable.
“…The irradiation of colchicine leads to the formation of β- and γ-lumicolchicine ( 3 and 4 ) (Scheme ). Prolonged irradiation times lead to the formation of α-lumicolchicone ( 2 ) (Scheme ). − β-Lumicolchicine is a biologically active compound 1 Photoisomerization of Colchicine …”
mentioning
confidence: 99%
“…Prolonged irradiation times lead to the formation of R-lumicolchicone (2) (Scheme 1). [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] β-Lumicolchicine is a biologically active compound. 22 Previous photolysis studies indicated that the quantum yield of colchicine conversion depends on solvent polarity.…”
The photochemical reactivity of colchicine and thiocolchicine is described. Although the irradiation of colchicine gave a well-known transposition reaction to -and γ-lumicolchicines, thiocolchicine did not react. Femtosecond transient spectroscopy of colchicine showed a strong band with maximum at 510 nm appearing at τ ) 0. It disappeared within few hundred femtoseconds, leaving a broad structureless band with a maximum around 470 nm. A second band is observed around 410 nm. The analysis in time showed that the 510-nm component appeared instantaneously and decayed following a biexponential low with time constants of 300 ( 100 fs and 40 ps. The kinetics at 420 nm has a measurable rise time of 300 ( 150 fs. Quantum mechanical calculations on colchicine showed that this absorption is due to a S 1 f S 11 transition. In thiocolchicine, the instantaneous formation of a structure with maxima out of the investigated spectral region was observed. A strong absorption around 650 nm indicated the presence of a band with a maximum at longer wavelengths (> 700 nm) and a peak around 380 nm, which partially coincides with the ground-state absorption and therefore strongly affected by its bleaching. The instantaneous formation of an absorption around 650 nm and its rapid (∼500 fs) decay was observed. At shorter wavelengths (400 nm), the decay was fitted with a biexponential curve with the first time constant of about 80 ps. The second part of the decay had a very long tail up to 500 ps. Transient spectroscopy and configuration interaction calculations are in agreement with a mechanism involving a disrotatory cyclization of colchicine in its first excited singlet state. The lack of reactivity observed in thiocolchicine was explained by considering the presence of efficient ISC to the triplet state.Colchicine (1) is the major alkaloid of Colchicum autumnale (autumn crocus) and Gloriosa superba (flory lily), Liliacee. It is an ancient drug used in medicine for its antimitotic, antiinflammatory, and antineoplastic effects. 1,2 It has been used as a neurotoxin in animal models of Alzheimer's disease and epilepsy. 3 Several derivatives have been synthesized in order to improve antitumor activity. [4][5][6] The irradiation of colchicine leads to the formation of -and γ-lumicolchicine (3 and 4) (Scheme 1). Prolonged irradiation times lead to the formation of R-lumicolchicone (2) (Scheme 1). 7-21 -Lumicolchicine is a biologically active compound. 22 Previous photolysis studies indicated that the quantum yield of colchicine conversion depends on solvent polarity. 23 This behavior was explained by assuming the formation of a solvation complex in the ground state. The nature of the excited state responsible for the formation of photoproducts has not been determined; the authors proposed that colchicine isomerization occurs from the triplet excited state. However, in a subsequent study, they did not observe any quenching effect of several triplet acceptors on the reactivity. 24 In a previous paper, we found that transient absorption spectrosc...
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