Baseninduzierte umlagerungen von 3,9 dioxatricyclo[3.3.1.02,4]nonan-7-onen zu m-hydroxyphenylcarbonyl-verbindungen

Föhlisch, Baldur; Herrscher, Otto

doi:10.1016/s0040-4020(01)96563-9

Cited by 12 publications

(5 citation statements)

References 14 publications

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“…The general procedure used for the synthesis of the target benzylimidazolines in Table is shown in Scheme . Nearly all of the requisite benzoic acid ( 36 ), benzyl alcohol ( 38 ), benzyl halide ( 39 ), and phenylacetonitrile ( 40 ) precursors were commercially available; the substituted benzaldehydes and benzoic acids necessary for the preparation of 17 − 19 , 30 , and 31 were synthesized according to literature methods. − In general, the intermediate benzyl alcohols 38 were prepared by reduction of the corresponding aldehydes 37 or acids 36 with NaBH 4 or LiAlH 4 , respectively. The alcohols were converted to the benzyl halides 39 by standard methods, and the halides were treated with NaCN to afford nitriles 40 .…”

Section: Chemistrymentioning

confidence: 99%

Benzylimidazolines as h5-HT_1B/1D Serotonin Receptor Ligands: A Structure−Affinity Investigation

et al. 1998

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Benzylimidazolines may represent a class of 5-HT1D ligands that has yet to be exploited. On the basis of a previous report that the 2-(substituted-benzyl)imidazoline alpha-adrenergic agonist oxymetazoline (8) binds with high affinity at calf brain 5-HT1D receptors, we explored the structure-affinity relationships of a series of related derivatives. Each of the aromatic substituents was removed and then reinstated in a systematic manner to determine the influence of the individual substituents on binding. It was found that all of the aromatic substituents of 8 act in concert to impart high affinity. However, although the 3-hydroxy group could be removed without significantly reducing affinity for h5-HT1D (i.e., human 5-HT1Dalpha) receptors, this modification reduced h5-HT1B (i.e., human 5-HT1Dbeta) receptor affinity by nearly 50-fold. The 2, 6-dimethyl groups also contribute to binding but seem to play a greater role for h5-HT1B binding than h5-HT1D binding. With the appropriate structural modifications, several compounds were identified that display 20- to >100-fold selectivity for h5-HT1D versus h5-HT1B receptors. Preliminary functional data suggest that these compounds behave as agonists. Given that 5-HT1D agonists are currently being explored for their antimigraine action and that activation of h5-HT1B receptors might be associated with cardiovascular side effects, h5-HT1D-selective agents may offer a new lead for the development of therapeutically efficacious agents.

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Section: Chemistrymentioning

confidence: 99%

Benzylimidazolines as h5-HT_1B/1D Serotonin Receptor Ligands: A Structure−Affinity Investigation

et al. 1998

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“…The unsatisfactory yields of [4+3] cycloadducts obtained from the heterosubstituted furans 1i − m prompted us to find a way to functionalize the exocyclic double bond in the alkenyl-substituted oxabicycles derived from the furans 1d,e,g and 1h . It was recorded earlier that m -chloroperbenzoic acid (MCPBA) readily epoxidizes the 6,7-double bond of bicyclo[3.2.1]oct-6-en-3-one and its 8-oxa derivatives …”

mentioning

confidence: 99%

Improved Syntheses and Some Selective Transformations of 2,2,4,4-Tetrachloro-8-oxabicyclo[3.2.1]oct-6-en-3-ones

et al. 1999

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The methyl- and alkenyl-substituted furans 1b-h react with pentachloroacetone (2) and sodium 2,2,2-trifluoroethoxide solution to form the title compounds 3b-h in good yield. With the furans 1i-m bearing an oxygen or a sulfur heteroatom in the side chain, moderate yields are obtained. Dechlorination of the [4+3] cycloadducts 3 with the Zn-Cu couple leads to the corresponding oxabicyclic ketones 4. On catalytic hydrogenation of the tetrachlorooxabicyclooctenones 3a-c hydrogenolysis of the exo-carbon-chlorine bonds occurs, leading to the endo-2,endo-4-dichloro-8-oxabicyclooctan-3-ones 8a-c. With lithium aluminum hydride and Grignard reagents, 8a and 3a form the endo-3-alcohols 12a-c and 13, respectively, the latter with uncertain configuration at C-3, in a highly stereoselective manner. The ether bridge in the dechlorinated oxabicyclooctenones 4b, 4f, and 4g can be cleaved by means of trimethylsilyl triflate/triethylamine to produce the tropones 5b, 5f, and 5g. Hydrogenation of 1,5-dimethyl-8-oxabicyclo[3.2.1]oct-6-en-3-one (4c), followed by Wolff-Kishner reduction, affords 1,5-dimethyl-8-oxabicyclo[3.2.1]octane (7). m-Chloroperbenzoic acid epoxidizes the alkenyl side chain of the tetrachlorinated oxabicycles 3d, 3e, 3g, and 3h in a site-selective reaction. In contrast, from the dehalogenated oxabicyclic ketone 4g the bis(epoxide) 14 is obtained.

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“…85-87°C (pentane) {lit. 97-98.5°C [ethyl acetate, [58] 93°C (CCl 4 ) [59] ]}. Spectral properties were in accordance with previous literature reports; [58,59] …”

Section: (-)-(5s)-5-tert-butyloxepan-2-one (7b)mentioning

confidence: 99%

Stereoselective Desymmetrizations by Recombinant Whole Cells Expressing the Baeyer–Villiger Monooxygenase from Xanthobacter sp. ZL5: A New Biocatalyst Accepting Structurally Demanding Substrates

et al. 2008

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In this work the substrate profile and stereoselectivity of engineered whole cells overexpressing the Baeyer–Villiger monooxygenase from Xanthobacter sp. ZL5 with respect to biotransformations of prochiral substrates is characterized. This enzyme catalyzes the desymmetrization of cyclic ketones bearing different chemical features with stereoselectivity similar to that obtained with a related protein fromAcinetobacter as a prototype representative of the cyclohexanone monooxygenase enzyme cluster. Moreover, this biocatalyst is able to convert sterically demanding substrates previously not transformed by other enzymes with excellent enantioselectivities. These results expand the repertoire of optically pure lactones accessible by whole‐cell biotransformation processes, which are useful intermediates for the synthesis of natural and bioactive products. In addition, we observed a remarkable epoxidation reaction of a non‐activated C=C bond catalyzed by this monooxygenase.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

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Baseninduzierte umlagerungen von 3,9 dioxatricyclo[3.3.1.02,4]nonan-7-onen zu m-hydroxyphenylcarbonyl-verbindungen

Cited by 12 publications

References 14 publications

Benzylimidazolines as h5-HT_1B/1D Serotonin Receptor Ligands: A Structure−Affinity Investigation

Benzylimidazolines as h5-HT_1B/1D Serotonin Receptor Ligands: A Structure−Affinity Investigation

Improved Syntheses and Some Selective Transformations of 2,2,4,4-Tetrachloro-8-oxabicyclo[3.2.1]oct-6-en-3-ones

Stereoselective Desymmetrizations by Recombinant Whole Cells Expressing the Baeyer–Villiger Monooxygenase from Xanthobacter sp. ZL5: A New Biocatalyst Accepting Structurally Demanding Substrates

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Baseninduzierte umlagerungen von 3,9 dioxatricyclo[3.3.1.02,4]nonan-7-onen zu m-hydroxyphenylcarbonyl-verbindungen

Cited by 12 publications

References 14 publications

Benzylimidazolines as h5-HT1B/1D Serotonin Receptor Ligands: A Structure−Affinity Investigation

Benzylimidazolines as h5-HT1B/1D Serotonin Receptor Ligands: A Structure−Affinity Investigation

Improved Syntheses and Some Selective Transformations of 2,2,4,4-Tetrachloro-8-oxabicyclo[3.2.1]oct-6-en-3-ones

Stereoselective Desymmetrizations by Recombinant Whole Cells Expressing the Baeyer–Villiger Monooxygenase from Xanthobacter sp. ZL5: A New Biocatalyst Accepting Structurally Demanding Substrates

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Benzylimidazolines as h5-HT_1B/1D Serotonin Receptor Ligands: A Structure−Affinity Investigation

Benzylimidazolines as h5-HT_1B/1D Serotonin Receptor Ligands: A Structure−Affinity Investigation