Spurenanalyse physiologisch aktiver, einfacher Indolderivate

Stahl, Egon; Kaldewey, Harald

doi:10.1515/bchm2.1961.323.1.182

Cited by 104 publications

(13 citation statements)

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“…This is the second report of sesterterpenes having the same carbon skeleton as variecolin (1). The absolute configurations of 1- 3 have not yet been determined.…”

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confidence: 82%

“…Further purification of the extract using lowpressure liquid chromatography (LPLC) yielded another new sesteterpene, designated variecolactone (3), having an orange coloration on spraying with modified Ehrlich's reagent. 1 We now report the structure determination of 2 and 3.The molecular formulas of variecolol (2) and variecolactone (3) were determined by HREIMS as C 25 H 38 O 2 and C 25 H 36 O 3 , respectively. The 1 H NMR signals of 2 were similar to those of variecolin (1), except for the appearance of two signals (δ 4.45 and 4.62) instead of the aldehyde proton at δ 9.13 in 1.…”

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confidence: 98%

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Two New Sesterterpenes from the Ascomycetous Fungus Emericella purpurea

et al. 1999

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Two new sesterterpenes, designated variecolol (2) and variecolactone (3), were isolated from the mycelium of Emericella purpurea, along with a sesterterpene, variecolin (1), which was recently isolated from Emericella variecolor as an angiotensin II receptor binding inhibitor, and an indoloditerpene, emindole PA. The structures of 2 and 3 were confirmed by spectroscopic investigation and chemical correlation with 1, and the direct X-ray analysis of 3, respectively.During a search for fungal indoloditerpenes, three components, one with a reddish coloration and the other two bluish when sprayed with modified Ehrlich's reagent, 1 were detected on TLC of a mycelial CH 2 Cl 2 extract of Emericella purpurea Samson & Mouchacca (Eurotiaceae) (IFO 30849). The former compound was an indoloditerpene, emindole PA, 2 whereas one of the other compounds was identical with variecolin (1), a sesterterpene recently isolated from E. variecolor Berkeley & Broome and shown to be an angiotensin II receptor binding inhibitor. 3 The third compound was a new sesterterpene designated variecolol (2). Further purification of the extract using lowpressure liquid chromatography (LPLC) yielded another new sesteterpene, designated variecolactone (3), having an orange coloration on spraying with modified Ehrlich's reagent. 1 We now report the structure determination of 2 and 3.The molecular formulas of variecolol (2) and variecolactone (3) were determined by HREIMS as C 25 H 38 O 2 and C 25 H 36 O 3 , respectively. The 1 H NMR signals of 2 were similar to those of variecolin (1), except for the appearance of two signals (δ 4.45 and 4.62) instead of the aldehyde proton at δ 9.13 in 1. The signals of 3 were also similar to those of 1, except for the absence of the aldehyde proton in 1. The vinylic proton signal at δ 6.97 in 1 was shifted upfield (δ 5.44) in 2, but this proton showed almost the same chemical shift (δ 6.96) in 3. From comparison of the molecular ion peaks in EIMS of 2 and 3 with 1, it was clear that 2 and 3 had two more hydrogens and one more oxygen, respectively, than 1. Therefore, we assumed that 2 and 3 had a carbinol group and a carboxylate residue, respectively, instead of the aldehyde residue in 1.Crystals of variecolactone (3) grew as colorless plates (MeOH) suitable for X-ray single crystallographic analysis. The crystal structure of 3 was established to be as shown in Figure 1. Two molecules of 3 existed independently in an asymmetric unit. These two molecules are tightly packed by two sets of hydrogen bonding between the oxygen atoms of the lactone carbonyl and the hydroxyl groups of the hemiketal [O(3)sH-O(2a) (2.923 Å) and O(3a)sH-O(2) (2.866 Å)]. Conformations of two molecules of 3 are quite similar, including the eight-membered rings, from the comparison of the torsion angles. Bond lengths and angles are not significantly different from those expected. 4 The relative structure of variecolactone was consequently established as shown in 3.To confirm the structure of 2, 1 was treated with sodium borohydride to obtain 2. T...

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“…This is the second report of sesterterpenes having the same carbon skeleton as variecolin (1). The absolute configurations of 1- 3 have not yet been determined.…”

mentioning

confidence: 82%

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confidence: 98%

Two New Sesterterpenes from the Ascomycetous Fungus Emericella purpurea

et al. 1999

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“…Thin layer chromatography was on precoated silica gel plates (F-254, Merck) using the following solvent systems: (a) ethyl acetate-methyl ethyl ketone-ethanol-water (5: Indolylic compounds were visualized using an Ehrlich spray reagent (20) or a modified Salkowski spray reagent (24). For general detection of organic compounds the plates were charred at 105 C for 15 min following spraying with concentrated sulfuric acid.…”

Section: Methodsmentioning

confidence: 99%

Purification and Partial Characterization of a Glucan Containing Indole-3-acetic Acid

Piskornik

Bandurski

1972

Plant Physiol.

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The "bound auxin" of Zea mays, first described by Berger and Avery (Amer. J. Bot. 1944; 31: 199-203) has been purified and partially characterized. It is an indole-3-acetic acidcontaining, high molecular weight, lipophilic cellulosieglucan. The indole-3-acetic acid is in ester linkage as evidenced by indoleacetamide formation upon ammonolysis. The glucan is of variable chain length and comprises, in general, 35 to 50 per cent of the dry weight of the compound. The glucosidic residues are ,8 1 -e 4 linked and are hydrolyzed by cellulase. Mild acid hydrolysis produces cellobiose and cellotriose. Other components, as yet unidentified, of the compound are described.Recent studies from this laboratory have been concerned with the characterization of the low molecular weight, watersoluble compounds of IAA isolated from the kernels of Zea mays (4,12,13,15,(25)(26)(27). These compounds, designated the B compounds by Labarca et al. (13), comprise almost one-half of the total indolylic compounds of corn and were found to be esters of IAA and either myoinositol or myoinositol glycosides. The remaining approximately one-half of the esterified IAA, the A fraction of Labarca et al. (13), has not been intensively studied in recent years. This, apparently high molecular weight and lipid-soluble fraction, was the original "bound auxin" of Berger and Avery (3, 5) and 9). These workers demonstrated that hydrolysis of the bound auxin by alkali or by passage through the human digestive tract led to the liberation of free IAA. This earlier work was confirmed and extended by Hemberg (11), Hamilton et al. (10), Labarca (12) and by Takano et al. (23). Collectively these workers demonstrated that the A fraction was probably of high molecular weight and that subsequent to alkaline hydrolysis, IAA was obtained from the fraction.We wish, in the present work, to describe methods for purification of the A fraction; to present evidence that the A-compound is an ester of IAA and a glucan of variable numbers of glucose residues; to present some properties of components of the compound other than IAA and glucan; and to demonstrate that the glucan is a cellulosic polysaccharide containing / 1 ->

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“…The corresponding migration positions were detected under U.V. light at 254 nm and by spraying with Van Urk's reagent (Stahl& Kaldewey, 1961). Ethyl acetate extracts were applied to a silica gel 60 column (SOX 5 cm) to obtain a larger amount of metabolites for spectroscopic studies.…”

Section: Salcher a N D F L I N G E N Smentioning

confidence: 99%