Citrus‐Carotinoide. 2. Mitteilung. Synthese von (3R)‐β‐Citraurin, (3R)‐β‐Citraurol und (3R)‐β‐Citraurinin; Aufklärung der Konfiguration von Citrus‐Carotinoiden

Pfander, Hanspeter; Lachenmeier, A.; Hadorn, M.

doi:10.1002/hlca.19800630604

Cited by 28 publications

(17 citation statements)

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“…␤-vinylionol (5, 5.5 g, 25 mmol) and 6 (8.55 g, 25 mmol) in 100 ml of methanol were allowed to react at room temperature for 48 h by the literature procedure (14,17). During this time, the triphenylphosphonium bromide dissolved, and the solution turned yellow.…”

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confidence: 99%

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Synthesis and characterization of a novel retinylamine analog inhibitor of constitutively active rhodopsin mutants found in patients with autosomal dominant retinitis pigmentosa

Snider

Oprian

1997

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

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Two different mutations of the active-site Lys-296 in rhodopsin, K296E and K296M, have been found to cause autosomal dominant retinitis pigmentosa (ADRP). In vitro studies have shown that both mutations result in constitutive activation of the protein, suggesting that the activated state of the receptor may be responsible for retinal degeneration in patients with these mutations. Previous work has highlighted the potential of retinylamine analogs as active-site directed inactivators of constitutively active mutants of rhodopsin with the idea that these or related compounds might be used therapeutically for cases of ADRP involving mutations of the active-site Lys. Unfortunately, however, amine derivatives of 11-cis-retinal, although highly effective against a K296G mutant of rhodopsin, were without affect on the two naturally occurring ADRP mutants, presumably because of the greater steric bulk of Glu and Met side chains in comparison to Gly. For this reason we synthesized a retinylamine analog one carbon shorter than the parent 11-cis-retinal and show that this compound is indeed an effective inhibitor of both the K296E and K296M mutants. The 11-cis C19 retinylamine analog 1 inhibits constitutive activation of transducin by these mutants and their constitutive phosphorylation by rhodopsin kinase, and it does so in the presence of continuous illumination from room lights.

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confidence: 99%

“…A solution of phosphonium salt 7 (12.5 g, 23 mmol) in 50 ml of anhydrous dimethylformamide under N 2 was cooled to 0°C. 6.0 g (28 mmol) of aldehyde 10 (18) was added, and 5 ml of 1,2-butene oxide was added dropwise (14,17,19). The mixture was stirred for 16 h at room temperature and then for 4 h at 60°C.…”

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confidence: 99%

Synthesis and characterization of a novel retinylamine analog inhibitor of constitutively active rhodopsin mutants found in patients with autosomal dominant retinitis pigmentosa

Snider

Oprian

1997

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

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“…Both isomers 14b and 14c could be transformed (64% from 14b; 70% from 14c) into the desired all-E one 14a by palladium-catalyzed isomerization. 17) Finally, C 25 -apocarotenal 14a was condensed with C 15 -Wittig salt 17, 18) which was prepared from trienoate 9 by reduction with LiAlH 4 followed by treatment with PPh 3 · HBr, to give the condensed products (quant. ), which was purified by preparative HPLC to afford all-E capsanthin (42%).…”

Section: )mentioning

confidence: 99%

Total Synthesis of Capsanthin Using Lewis Acid-Promoted Regio- and Stereoselective Rearrangement of Tetrasubstituted Epoxide.

Yamano

Ito

2001

CHEMICAL & PHARMACEUTICAL BULLETIN

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The synthesis of capsanthin 1 was accomplished via the C 15 -cyclopentyl ketone 13 prepared by Lewis acid-promoted regioand stereoselective rearrangement of the epoxide 12.Key words capsanthin; tetrasubstituted epoxide; regio-and stereoselective rearrangement; total synthesis Previously, we reported 1) the first biomimetic type total synthesis of both crassostreaxanthin B 2 (Fig. 1) possessing a novel acyclic-tetrasubstituted olefinic end group and mytiloxanthin 3 containing a cyclopentyl enolic b-diketone group applying stereoselective rearrangement of tetrasubstituted epoxide.2) In these syntheses, we employed epoxides, in which substituents at the C-63) position were alkyl groups having an oxygen functional group as shown in Chart 1.Capsanthin 1 (Fig. 1), having a k-end group, is a main pigment of red paprika Capsicum annuum and has become the center of attention due to its strong antioxidant activities. 4) There has been only one report by Weedon's group 5) concerning its synthesis. Here, we describe the total synthesis of 1 via regio-and stereoselective rearrangement of the C 15 -epoxide 12 (Chart 3) having a conjugated olefinic group at C-6, which was efficiently derived from the optically active (4R,6R)-4-hydroxy-2,2,6-trimethylcyclohexanone. 6) It has been known that the rearrangement of the epoxide 4b 7) (Chart 2) only provided the flanoid 5b by opening of C-6-oxygen bond of the oxirane ring (route a) and subsequent migration of the 7,8-double bond, whereas that of the epoxide 4a 8) predominantly produced the cyclopentyl ketone 6a by cleavage of the oxirane ring at the C-5 position (route b) and successive ring contraction. It is considered that the selective cleavage of epoxide 4a at C-5 was promoted by destabilization of the cation at C-6 due to the electron deficiency of 7(b)-carbon on a,b-unsaturated carbonyl group.Thus, the reaction of epoxides 4c-e 9) having an olefinic group conjugated to a carbonyl group at C-6 (Chart 2) was investigated toward the synthesis of 1. As a result, treatment of the epoxide 4d with SnCl 4 was found to give predominantly the desired cyclopentyl ketone 6d (91%). On the other hand, the reaction of the epoxides 4c and 4e with SnCl 4 preferentially provided flanoids 5c (86%; 5,8-trans 10) : 5,8-cis 10) ϭ8 : 1) and 5e (53%; 5,8-trans : 5,8-cisϭ5 : 1). These results show that the direction of C-O bond cleavage in the oxirane ring depends upon both the length of conjugated double bond system and the electron-withdrawing ability of the substituent adjacent to the double bond.In order to synthesize 1, C 15 -epoxide 12 was prepared via stereo-controlled cross-coupling reaction of the vinylstannane 8 with the vinyl triflate 15 11) as shown in Chart 3. The known 12) terminal alkyne 7, prepared (62%) from (4R,6R)-4-hydroxy-2,2,6-trimethylcyclohexanone, 6) was heated at 130°C for 20 min with an excess amount (4 eq) of Bu 3 SnH in the presence of a catalytic amount of azobisisobutyronitrile (AIBN) 13) to give stereoselectively the E-vinylstannane 8 in 88% yield. Cross-coupling rea...

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“…IR (Film): 2920s, 28603, 17303, 1450m, 1360m, 1230s, 1190w, 1160m, 1 IOOs, 1040s, Y70m, 84Ow. ( (7), 89 (62), 84 (12), 73 (6), 59 (100). (7), 54 (IOO), 45 (15).…”

Section: Essigsiiure-{ ( 3 R) -3-/3'-( (2-methoxyethoxy) Methoxy)methmentioning

confidence: 99%

C₄₅‐ und C₅₀‐Carotinoide. 5. Mitteilung

Wolleb

Pfander

1986

Helvetica Chimica Acta

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The synthesis of the optically active C,,-building block (R)-16 and of the optically active Cso-carotenoid C.p. 173 (1) starting from (-)-b-pinene is reported.Einleitung. -Aus Corynebacterium poinsettiae wurden vor einiger Zeit die beiden Zyclischen C,,-Carotinoide C.p. 450 und C.p. 473 isoliert [2] [3]. Neuere Untersuchungen :4-6] zeigten, dass dem C.p. 450 die Struktur von (2R,2'R)-2,2'-Bis(4-hydroxy-3-methylbut-2-enyl)-P,P-carotin und dem C.p. 473 (1) diejenige von (2R,2'S)-3',4'-Didehydro-1 ',2'-dihydro-2-(4-hydroxy-3-methylbut-2-enyl)-2'-(3-methylbut-2-enyl)-~, Y-carotin-1'-01 zukommt. Kurzlich haben wir uber die Synthese von zwei optisch aktiven C,,-Bausteinen sowie des C,,-Carotinoids C.p. 450 in optisch aktiver Form ausgehend von (-)$-Pinen berichtet [ 11.-1 In der vorliegenden Arbeit berichten wir uber die Synthese von optisch aktivem C.p. 473 (1) sowie eines weiteren optisch aktiven C,,-Bausteins, welcher, wie ursprunglich fur C.p. 450 vorgeschlagen [2] [3], zwei potentielle OH-Gruppen in der Prenyl-Seitenkette aufweist . Ergebnisse und Diskussion. -1. Synthese des optisch aktiven C,-Bausteins (R) -16. Das Ausgangsmaterial (R)-2 (hergestellt aus (-)$-Pinen in 11 Stufen gemass [l]) wurde zunachst mit Ac,O/Pyridin und 4-(Dimethy1amino)pyridin als Katalysator zu (R)-3 ') 4. Mitteilung, s. [I].

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Citrus‐Carotinoide. 2. Mitteilung. Synthese von (3R)‐β‐Citraurin, (3R)‐β‐Citraurol und (3R)‐β‐Citraurinin; Aufklärung der Konfiguration von Citrus‐Carotinoiden

Cited by 28 publications

References 4 publications

Synthesis and characterization of a novel retinylamine analog inhibitor of constitutively active rhodopsin mutants found in patients with autosomal dominant retinitis pigmentosa

Synthesis and characterization of a novel retinylamine analog inhibitor of constitutively active rhodopsin mutants found in patients with autosomal dominant retinitis pigmentosa

Total Synthesis of Capsanthin Using Lewis Acid-Promoted Regio- and Stereoselective Rearrangement of Tetrasubstituted Epoxide.

C₄₅‐ und C₅₀‐Carotinoide. 5. Mitteilung

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Citrus‐Carotinoide. 2. Mitteilung. Synthese von (3R)‐β‐Citraurin, (3R)‐β‐Citraurol und (3R)‐β‐Citraurinin; Aufklärung der Konfiguration von Citrus‐Carotinoiden

Cited by 28 publications

References 4 publications

Synthesis and characterization of a novel retinylamine analog inhibitor of constitutively active rhodopsin mutants found in patients with autosomal dominant retinitis pigmentosa

Synthesis and characterization of a novel retinylamine analog inhibitor of constitutively active rhodopsin mutants found in patients with autosomal dominant retinitis pigmentosa

Total Synthesis of Capsanthin Using Lewis Acid-Promoted Regio- and Stereoselective Rearrangement of Tetrasubstituted Epoxide.

C45‐ und C50‐Carotinoide. 5. Mitteilung

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C₄₅‐ und C₅₀‐Carotinoide. 5. Mitteilung