Synthese von <i>rac</i>‐Detoxinin

Häusler, Johannes

doi:10.1002/jlac.198319830611

Cited by 24 publications

(10 citation statements)

References 22 publications

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“…Using a two-step procedure of column chromatography on A1203 with different eluents, 3,6-dimethyl-9-phenyl-l,3,4,5,6,8,9,10octahydropyrano-[4,3-b:4',3'-e]-pyridine-1,8-dione (3) was isolated from the original reaction mixture in small yields. 4 The assumed structure of this compound is strongly supported by the results of elemental analysis and 'H-NMR and IR spectroscopic measurements. As expected, the UV spectrum of compound 3 contains the intensive long-wavelenght absorption band of 1,2dihydropyridines at 357 nm indicating a T, T* transition.…”

Section: 1 O-octahydropyrano-[43-b:4/3'-e]-pyridine-18-dione (3)mentioning

confidence: 78%

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Photophysics and photochemical reactions with electron acceptors of an anellated HANTZSCH-ester

Ulrich

Timpe²

1995

J. Prakt. Chem.

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3,6-Dimethyl-9-phenyl-l,3,4,5,6,8,9,1O-octahydropyrano-[4,3-b:4',3'-e]-pyridine-l,8-dione (3) was prepared as first derivative of a novel substance class exhibiting a 1,4dihydropyridine structural element. Diazonium, iodonium, sulfonium and phosphonium salts act as electron acceptors both for ground state charge transfer complex formation and in single electron transfer processes (SET) with excited states of compound 3. Solvents strongly influence the rate constants of fluorescence quenching. Those containing a hydroxyl group decrease these rate constants as well as the quantum yields of SET due to higher solvent reorganization energies. Some expressions have been developed to describe the strong solvent effect. Due to a less effective population of the triplet state, the quantum yields of the SET'S are low.

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Section: 1 O-octahydropyrano-[43-b:4/3'-e]-pyridine-18-dione (3)mentioning

confidence: 78%

“…Experimental 6-Methyltetrahydropyane-2,4-dione (4) was prepared according to a procedure given in ref. [4] (m. p. 121-123°C). 2.58 g (0.02 mol) of this dione were heated for 3 h together with 1.06 g (0.01 mol) freshly distilled benzaldehyde and 2.31 g (0.03 mol) ammonium acetate in 75 ml methanol.…”

mentioning

confidence: 99%

Photophysics and photochemical reactions with electron acceptors of an anellated HANTZSCH-ester

Ulrich

Timpe²

1995

J. Prakt. Chem.

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“…Glasshouse tests have shown that detoxins decrease the phytotoxicity of the rice blast fungicide Blasticidin S—a nucleoside antibiotic—without interfering with its desired properties. Total syntheses of racemic14 and enantiopure detoxinine15 have been reported. In general, these involve many steps with complex reagents, since the dense sequence of functional groups and the three stereogenic centers of the natural product are rather challenging.…”

Section: Resultsmentioning

confidence: 99%

A Stereoselective and Short Total Synthesis of the Polyhydroxylated γ‐Amino Acid (−)‐Detoxinine, Based on Stereoselective Preparation of Dihydropyrrole Derivatives from Lithiated Alkoxyallenes

Flögel

Amombo

Reißig

et al. 2003

Chemistry A European J

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Based on our earlier results employing lithiated methoxyallene 2 as C(3) building block and imines 3 for the synthesis of dihydropyrrole derivatives 5, we have investigated chiral imines 6, 10, and 15 as electrophilic components. Combined with lithiated alkoxyallenes, these imines provide the corresponding primary adducts and finally the dihydropyrrole derivatives 8, 12, 17, 20, and 22 in good yields and with high to excellent syn selectivities. This stereochemical outcome is interpreted as a result of alpha-chelate control. Treatment with hydrochloric acid converted syn-8 and syn-12 into bicyclic compounds 9 and 13, whereas under more mildly acidic conditions adduct syn-17 was transformed into diol syn-18. The total synthesis of the uncommon gamma-amino acid (-)-detoxinine could be achieved by starting from (S)-malic acid, which was converted into imine 15 in four steps. Lithiated benzyloxyallene added to imine 15 and efficiently furnished the crucial dihydropyrrole derivative syn-22. The hydrogenolysis of this compound did not directly provide the protected triol 29 as anticipated, but a stepwise protocol made the triol available in a fairly satisfactory manner. A second crucial step of the synthesis was the selective oxidation of 29, which could be achieved by employing platinum dioxide and oxygen. The resulting bicyclic lactone 30 was smoothly transformed into enantiopure (-)-detoxinine. Thus, a fairly short synthesis of this natural product based on a lithiated alkoxyallene could be performed, demonstrating the potential of these intermediates for syntheses of interesting functionalized heterocyclic compounds.

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“…Das Diastereomere 15a mit freier Hydroxygruppe an C-7 wurde nun in den THP-Ether 17 ubergefiihrt und dieser nachfolgend der Ringoffnungs-, Veresterungs-und Acetylierungsprozedur unterworfen, die sich bei den Hydroxypyronen (3aR*,7R*,7aR*) -7-Acetyloxy-l-tert-butyloxycarbonyl-l,2,3,3a,S,6,7,7a-octahydropyra- no[3,2-b] 20 H 6.99 N 4.78 (3aR*,7R*,2,3,3a,S,~,7, ( 3 R*) -3 -I 2R* ,3 R*) -3- Acetoxy-1 -tert-hutyloxycurbonyl-2-pyrrolidinyl/-3- 4) in fast quantitativer Ausbeute kristallin an. Zu einer Suspension von 1.35 g (5.0 mmol) Trifluoracetat und 2.56 g (5.3 mmol) (S)-N-(Benzyioxycarbonyl)valin-anhydrid3) in 25 ml wasserfreiem Acetonitril wurdcn bei -5°C 1.1 1 g (1 1.0 (3aR,7S,7aR) -I -[ (2S)-2-Benzyloxycarbonylamino-3-methyl-i-oxobutyl I- 1,2,3,3a,5,6,7,7aoctahydro-7-hydroxypyrano(3,2-b/pyrvol-S-o~ 1-((2S/-2-Acetylamino-3-methyl-~-oxobutyl]-i,2,3,3a,5,6,7,7a-octahydro-7 Das ((3aS,7R,7aS) (3aR,7S, 7aRj -1 -((2S) -2-Benzyloxycarbonylamino-3-methyl-l-oxobutyl]-l,2,3.3a,5,6,7aoctahydro-7-(tetrahydropyran-2-yloxy)pyrano[3,2-b]pyrro1-5-on (17 C2SH34N207 (474.5) Ber.…”

Section: Synthese Des Detoxin Dunclassified

Synthese von (−)‐Detoxin D₁

Häusler

1986

Liebigs Ann. Chem.

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Untersuchungen an den Oxylactonen 3-8 zeigen, daB sich mit waBriger Alkalilauge lediglich bei den Hydroxylactonen 3 und 4 sowie beim Tetrahydropyranylether 8 der Lactonring ohne P-Eliminierung des 7-Oxyrests offnen laBt, nicht jedoch bei den empfindlicheren Acyloxylactonen 5-7. Die bei der Lactonringoffnung von 4, 8 und 14 anfallenden Alkalicarboxylate werden mit Benzylbromid verestert und gegebenenfalls acetyliert (Produkte 9, 12, 13 und 23). Abspaltung der Schutzgruppe von 13 liefert neben wenig Umacylierungsprodukt 11 den Hydroxyester 10. -Acylierung von racemischem Detoxininlacton 3 mit (S)-Valin ergibt das Diastereomerengemisch der Valyldetoxininlactone 15a und b, das aufgetrennt wird. Das naturlich konfigurierte 15a wird analog zur Darstellung von 10 aus 4 zum Valyldetoxinin 19 umgesetzt. Diese Syntheseschritte verlaufen jedoch uneinheitlicher (Eliminierungsprodukte 22a und 24). Der Aufbau der Seitenkette fuhrt schlieBlich uber 20 und 21 zur Titelverbindung 1. Synthesis of (-)-Detoxine D,Experiments with the oxylactones 3-8 show that on treatment with alkaline solution lactone ring opening occurs without p-elimination of the 7-oxy substituent only with the hydroxylactones 3 and 4 and the tetrahydropyranyl ether 8, but not with the more sensitive acyloxylactones 5-7. The alkali carboxylates produced by the ring opening of the lactones 4,8, and 14 are esterified with benzyl bromide and are subsequently acylated in some cases (products 9, 12, 13, and 23). Cleavage of the protection group in 13 yields the hydroxy ester 10 besides of a little transacylated product 11. -Acylation of the racemic detoxinine lactone 3 with (S)-valine leads to a diastereomeric mixture of the valyldetoxinine lactones 15a and b which are separated. Analogously to the synthesis of 10 from 4, the naturally configurated 15a is transformed into the valyldetoxinine 19. These synthetic steps proceed less homogenously (elimination products 22a and 24). The completion of the side chain via 20 and 21 finally leads to the title compound 1.Detoxin D1 (l), der Hauptvertreter einer Gruppe nahe verwandter Depsipeptide aus Streptomyces caespitosus var. detoxicus wurde vom Arbeitskreis urn Kakinuma') isoliert und strukturell aufgeklart. Es zeigt potente antagonistische Aktivitat gegen eine durch Blasticidin S in lebenden Zellen verursachte Toxizitat la).Den zentralen Baustein von 1 bildet die cyclische y-Amino-0-bdihydroxycarbonsaure Detoxinin (2), deren Stickstoff den (S)-Valylrest und deren Sauerstoffe den Acetyl-bzw. N-[(S)-2-Methyl-l -oxobutyl]-(S)-phenylalanin-Rest tragen. Vor kurzem fanden wir einen synthetischen Zugang zum racemischen 2*) und berichten nun uber den Aufbau der Titelverbindung 1. Wesentlich fur die Synthese war,

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Synthese von rac‐Detoxinin

Cited by 24 publications

References 22 publications

Photophysics and photochemical reactions with electron acceptors of an anellated HANTZSCH-ester

Photophysics and photochemical reactions with electron acceptors of an anellated HANTZSCH-ester

A Stereoselective and Short Total Synthesis of the Polyhydroxylated γ‐Amino Acid (−)‐Detoxinine, Based on Stereoselective Preparation of Dihydropyrrole Derivatives from Lithiated Alkoxyallenes

Synthese von (−)‐Detoxin D₁

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Synthese von rac‐Detoxinin

Cited by 24 publications

References 22 publications

Photophysics and photochemical reactions with electron acceptors of an anellated HANTZSCH-ester

Photophysics and photochemical reactions with electron acceptors of an anellated HANTZSCH-ester

A Stereoselective and Short Total Synthesis of the Polyhydroxylated γ‐Amino Acid (−)‐Detoxinine, Based on Stereoselective Preparation of Dihydropyrrole Derivatives from Lithiated Alkoxyallenes

Synthese von (−)‐Detoxin D1

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Synthese von (−)‐Detoxin D₁