Über eine neuartige Synthese von β‐Ketoallenen durch Reaktion von tertiären Acetylencarbinolen mit Vinyläthern eine ergiebige methode zur darstellung des Pseudojonons und verwandter verbindungen

Saucy, G.; Marbet, R.

doi:10.1002/hlca.19670500423

Cited by 111 publications

(28 citation statements)

References 20 publications

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“…Position 4 is furthermore completely deuterated and position 2 only 50% deuterated. These results are to be expected on the basis of the synthetic pathway (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21). Whether position 3 is deuterated cannot be decided from the 1H NMR spectrum because of the overlap with the H20 peak at this 8.…”

Section: Methodssupporting

confidence: 55%

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Location of the cyclohexene ring of the chromophore of bacteriorhodopsin by neutron diffraction with selectively deuterated retinal

Seiff

Westerhausen²,

Wallat³

et al. 1986

Proc. Natl. Acad. Sci. U.S.A.

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We report on the location of the cyclohexene ring of the retinylidene chromophore of bacteriorhodopsin projected onto the plane of the membrane. For this purpose, partially deuterated retinal was synthesized containing 11 deuterons at the following positions ofthe cyclohexene ring: one at C-2, two at C-4, three at C-16, three at C-17, and two at C-18. The partially deuterated retinal was incorporated biosynthetically during growth of the bacteria by using the mutant JW5, which is deficient in the synthesis of retinal. Undeuterated samples were prepared in the same way. Characterization by x-ray diffraction and absorption spectroscopy showed that these samples are identical to native purple membranes as judged by these criteria. A Fourier difference map was calculated from the differences in in-plane diffraction intensities between the deuterated and undeuterated darkadapted membrane samples. Model calculations showed that the observed difference density had the amplitude expected for a label containing 11 deuterons. At 8.7 A resolution, the map shows one major peak with the center of mass of the deuterated ring in the interior of the molecule between helices 3, 4, 5, and 6. Based on this result and on our previous work on the location of the middle of the polyene chain, we conclude that the COOH-terminal helix G, to which retinal is attached at lysine-216, is either helix 2 or helix 6.The chromophore of bacteriorhodopsin is of central importance in the photochemistry and in the charge cycle of this light-driven proton pump (1). Fluorescence energy transfer (2, 3) and neutron diffraction with perdeuterated retinal (4,5) have been used in attempts to determine the location of retinal in the projected density of bacteriorhodopsin. Since retinal is 15 A long in its all-trans form and since its polyene chain makes an angle of =20°with the plane of the membrane (6), the mass density of retinal projected onto the plane of the membrane will be smeared out and elongated. Low-resolution neutron diffraction experiments with perdeuterated retinal (28 deuterons) will therefore determine only the center of deuteration of this delocalized mass distribution. More detailed structural information about the location of the various parts of retinal may be obtained by using partially deuterated retinal. This method was recently applied with a synthetic retinal containing 10 deuterons to determine the position of the middle of the polyene chain (C-11) (7). In the present work, we continue this approach with a synthetic retinal that was selectively labeled with 11 deuterons in the cyclohexene ring to find the location of the ring (Fig. 1). Taken together, the results of these two studies provide a low-resolution map of the arrangement and orientation of the chromophore within bacteriorhodopsin and allow an estimate to be made of the position of the Schiffs base nitrogen. The result limits the assignment of helix G of the sequence to which the chromophore is attached at lysine-216 to helix 2 or 6 of the structure. MATERIALS AND...

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Section: Methodssupporting

confidence: 55%

“…The [2,4,4,16,16,16,17,17,17,18,18-2H11]retinal ( Fig. 1) was synthesized according to the methods described (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21). The product was purified by chromatography (5% ether/hexane; silica gel, <230 mesh) and characterized by UV spectroscopy, 1H NMR and mass spectroscopy.…”

Section: Methodsmentioning

confidence: 99%

Location of the cyclohexene ring of the chromophore of bacteriorhodopsin by neutron diffraction with selectively deuterated retinal

Seiff

Westerhausen²,

Wallat³

et al. 1986

Proc. Natl. Acad. Sci. U.S.A.

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“…Allenes have long been versatile platforms for reaction discovery and development . They form the basis of a number of widely used transformations which include: cyclizations, annulations, photocycloadditions, hydro‐heterofunctionalizations, and rearrangements . Their ease of preparation, combined with their broad applications in stereoselective catalysis has greatly increased their utility as building blocks in organic synthesis .…”

Section: Methodsmentioning

confidence: 99%

Ir‐Catalyzed Enantioconvergent Synthesis of Diversely Protected Allenylic Amines Employing Ammonia Surrogates

Glatz¹,

Petrone²,

Carreira³

2020

Angew Chem Int Ed

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The first iridium catalyzed, enantioconvergent amination of allenylic carbonates is reported. This process utilizes various commercially available carbamates and sulfonamides to generate allenylic amines including commonly employed protected groups (Boc, Fmoc, Cbz, Ts, Ns) in 62–82 % yield and 87–98 % ee. The products generated through this scalable procedure serve as effective linchpins for the rapid, enantiospecific synthesis of a wide range of complex structures.

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“…Treatment of the product 13 with 2-methoxyprop-1-ene 10 upon acid catalyzed condition afforded 3,7-dimethyl-3-(prop-1-en-2-yloxy)oct-6-en-1-yne 14 , which underwent a Cope rearrangement to give the allenic ketone 15 . Compound 15 is isomerized to pseudoionone 16 [ 78 ]. Pseudoionone 16 is cyclized into β-ionone 17 in the presence of sulphuric acid.…”

Section: Hoffmann-la Roche Dsmmentioning

confidence: 99%

Synthesis and Use of Stable Isotope Enriched Retinals in the Field of Vitamin A

Dawadi

Lugtenburg

2010

Molecules

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Abstract:The role of vitamin A and its metabolites in the life processes starting with the historical background and its up to date information is discussed in the introduction. Also the role of 11Z-retinal in vision and retinoic acid in the biological processes is elucidated. The essential role of isotopically enriched systems in the progress of vision research, nutrition research etc. is discussed. In part B industrial commercial syntheses of vitamin A by the two leading companies Hoffmann-La Roche (now DSM) and BASF are discussed. The knowledge obtained via these pioneering syntheses has been essential for the further synthetic efforts in vitamin A field by other scientific groups. The rest of the paper is devoted to the synthetic efforts of the Leiden group that gives an access to the preparation of site directed high level isotope enrichment in retinals. First the synthesis of the retinals with deuterium incorporation in the conjugated side chain is reviewed. Then, 13 C-labeled retinals are discussed. This is followed by the discussion of a convergent synthetic scheme that allows a rational access to prepare any isotopomer of retinals. The schemes that provide access to prepare any possible isotope enriched chemically modified systems are discussed. Finally, nor-retinals and bridged retinals that give access to a whole (as yet incomplete) library of possible isotopomers are reviewed.

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Über eine neuartige Synthese von β‐Ketoallenen durch Reaktion von tertiären Acetylencarbinolen mit Vinyläthern eine ergiebige methode zur darstellung des Pseudojonons und verwandter verbindungen

Cited by 111 publications

References 20 publications

Location of the cyclohexene ring of the chromophore of bacteriorhodopsin by neutron diffraction with selectively deuterated retinal

Location of the cyclohexene ring of the chromophore of bacteriorhodopsin by neutron diffraction with selectively deuterated retinal

Ir‐Catalyzed Enantioconvergent Synthesis of Diversely Protected Allenylic Amines Employing Ammonia Surrogates

Synthesis and Use of Stable Isotope Enriched Retinals in the Field of Vitamin A

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