Synthesis of the dioxabicyclononane unit of tirandamycin

KELLY, T. R.; Chandrakumar, Nizal S.; Cutting, J. D.; Goehring, R. Richard; Weibel, Franz R.

doi:10.1016/s0040-4039(00)98954-8

Cited by 22 publications

(3 citation statements)

References 20 publications

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“…The acid-catalyzed apomorphine rearrangement or vinyl ether hydrolysis during 3-O-demethylation was prevented by unusual protecting group chemistry. [12,25] Our method employs protection of the cyclohexadiene moiety in thebaine 1 with either iron(0) pentacarbonyl developed by Birch [19,20] or as a bicyclic dihydrothiopyran-Diels-Alder adduct. [21][22][23][24]…”

Section: Introductionmentioning

confidence: 99%

Conversion of Thebaine to Oripavine and Other Useful Intermediates for the Semisynthesis of Opiate‐Derived Agents: Synthesis of Hydromorphone

et al. 2014

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Thebaine was converted to oripavine in three steps by employing two different modes of protection of the diene moiety; as an iron tricarbonyl complex and as a Diels-Alder adduct with thioformyl cyanide. The two C-ring-protected thebaine derivatives were subjected to 3-O-demethylation by four different protocols, providing oripavine derivatives, which yielded oripavine after deprotection. Oripavine was then converted to hydromorphone by a three-step process of ketalization, hydrogenation, and deprotection, without the isolation of intermediates.

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Section: Introductionmentioning

confidence: 99%

Conversion of Thebaine to Oripavine and Other Useful Intermediates for the Semisynthesis of Opiate‐Derived Agents: Synthesis of Hydromorphone

et al. 2014

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“…The 4-aminothiazoles were constructed as shown in Scheme 4 . Treatment of acetonitrile with LDA followed by addition of epoxide 5 gave trans -alcohol 24 [ 14 ]. The nitrile group was converted to a thioamide using ammonium sulfide [ 15 ].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and enzymatic evaluation of 2- and 4-aminothiazole-based inhibitors of neuronal nitric oxide synthase

Lawton¹,

Ji²,

Martásek³

et al. 2009

Beilstein J. Org. Chem.

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SummaryHighly potent and selective inhibitors of neuronal nitric oxide synthase (nNOS) possessing a 2-aminopyridine group were recently designed and synthesized in our laboratory and were shown to have significant in vivo efficacy. In this work, analogs of our lead compound possessing 2- and 4-aminothiazole rings in place of the aminopyridine were synthesized. The less basic aminothiazole rings will be less protonated at physiological pH than the aminopyridine ring, and so the molecule will carry a lower net charge. This could lead to an increased ability to cross the blood-brain barrier thereby increasing the in vivo potency of these compounds. The 2-aminothiazole-based compound was less potent than the 2-aminopyridine-based analogue. 4-Aminothiazoles were unstable in water, undergoing tautomerization and hydrolysis to give inactive thiazolones.

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“…In their publication, Ramig and co-workers did not mention the use of magnesium for the cyclization step but mentioned two papers which described magnesium-metal based cyclizations to γ-lactones in moderate yields. , A number of researchers have found ways to utilize Grignard reagents in the preparation of ketones from carboxylic acid derivatives by various methods . The large-scale use of magnesium rather than zinc is advantageous due to fewer disposal issues with magnesium salt wastes.…”

Section: Introductionmentioning

confidence: 99%

Enantioselective Synthesis of a Key Intermediate in a New Process for Orlistat Using Asymmetric Hydrogenation and a Grignard Reagent Promoted Lactone Cyclization

Schwindt

Fleming

Han

et al. 2007

Org. Process Res. Dev.

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A new enantioselective synthesis of Orlistat suitable for largescale preparation is described. Therein, the first isolated key intermediate (R)-3-hexyl-5,6-dihydro-4-hydroxy-6-undecyl-2Hpyran-2-one (12) is prepared via (a) the asymmetric hydrogenation of methyl 3-oxotetradecanoate to (S)-3-hydroxytetradecanoate (9); (b) the acylation of 9 with 2-bromooctanoyl halide (bromide/chloride) to (R)-3-[(2-bromo-1-oxooctyl)oxy]-tetradecanoic acid methyl ester (11) and finally (c) the tert-butyl magnesium chloride promoted cyclization of 11 to the single enantiomer 12. The single enantiomer intermediate 12, previously published as a mixture of enantiomers 2, has been carried on through several steps to Orlistat (1) without any process changes.

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Synthesis of the dioxabicyclononane unit of tirandamycin

Cited by 22 publications

References 20 publications

Conversion of Thebaine to Oripavine and Other Useful Intermediates for the Semisynthesis of Opiate‐Derived Agents: Synthesis of Hydromorphone

Conversion of Thebaine to Oripavine and Other Useful Intermediates for the Semisynthesis of Opiate‐Derived Agents: Synthesis of Hydromorphone

Synthesis and enzymatic evaluation of 2- and 4-aminothiazole-based inhibitors of neuronal nitric oxide synthase

Enantioselective Synthesis of a Key Intermediate in a New Process for Orlistat Using Asymmetric Hydrogenation and a Grignard Reagent Promoted Lactone Cyclization

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