Tobacco Chemistry. 65. Two New 7,8-Epoxycembranoids from Tobacco.

Wahlberg, Inger; Eklund, Ann-Marie; Vogt, Carmen; Enzell, Curt R.; Berg, Jan-Eric; Ljungqvist, Anders

doi:10.3891/acta.chem.scand.40b-0855

Cited by 13 publications

(15 citation statements)

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“…-Die erste Verbindung rnit 7-0xabicyclo[2.2.l]heptan-Gerust und prasumptiver Carotinoid-Herkunft wurde von Wahlberg et al [2] sowie von Takagi und Mitarbeitern [3] aus den Aromastoffen von fermentiertem Tabak in Form der optisch aktiven Verbindung 1 isoliert. Eine erste Partialsynthese liess sich durch Saurebehandlung am ebenfalls aus Tabak isolierten Violaxanthin-Abbauprodukt 2 ausfuhren [2] (Schema I ) . Hauptprodukt dieser Reaktion war allerdingswas nicht erstauntdas furanoide 5,g-Epoxid 3.…”

Section: Carotinoide Rnit 7-0xabicyclo[22l]heptyl-endgruppenunclassified

“…Bei 6 und 7 wurde zudem eine Verknupfung mit (3R,3'R)-Zeaxanthin erreicht. Die bei 2 erwahnte Umwandlung in 1 [2] ist bei den Carotinoiden 5-7, deren Vorlaufer bekannt sind, noch nicht durchgefuhrt worden. In Frage kamen Capsanthin-5,6-epoxid -+ 5, Antheraxanthin -+ 6, Violaxanthin -+ 7 -+ 8.…”

Section: Carotinoide Rnit 7-0xabicyclo[22l]heptyl-endgruppenunclassified

“…s, OH); 2,28 (s,CH,(19)); 2,67 (br. s, OH); 4, OO (ddd, Jax = 12,4, J,, = 3,6, J = 3,3, H-C(3)); = 9,4,4,4,); 1,91 (ddd, *J = 13,2, 3J = 10, 8, 4,6, H,,-C(5)); 2,Ol (ddd, *J = 13,5, 'J = 9,4, 4,6, (CH,-C(4)); 16,3 (2 CH,-C(7)); 28,5 (C(5)); 30,3 (C(6)); 52,O (COOCH,); 53,7 (C(4)); 54,3 (C (7)); 90,7 C(1)); (7)).…”

Section: Methyl-camphanoat ( = Methyl-477-trimethyl-3-oxo-2-oxabicymentioning

confidence: 99%

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Carotinoide mit 7‐Oxabicyclo[2.2.1]heptyl‐Endgruppen. Teil I. Versuch einer Synthese von Cycloviolaxanthin (= (3S,5R,6R,3′S,5′R,6′R)‐3,6:3′,6′‐Diepoxy‐5,6,5′,6′‐tetrahydro‐β,β‐carotin‐5,5′‐diol)

Gmünder

Eugster

1990

Helvetica Chimica Acta

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Carotenoids with 7‐Oxabicyclo[2,2.1]heptyl End Groups. Attempted Synthesis of Cycloviolaxanthin ( = (3S,5R,6S,3′S,5′R,6′R)‐3,6:3′,6′‐ Diepoxy‐5,6,5′,6′‐tetrahydro‐β,β‐carotin‐5,5′‐diol) Starting from our recently described synthon (+)‐24, the enantiomerically pure 3,6:4,5:3′,6′:4′,5′‐tetraepoxy‐4,5,4′,5′‐tetrahydro‐ε,ε‐carotene (34) and its 15,15′‐didehydro analogue 32 were synthesized in eleven and nine steps, respectively (Scheme 4). Chiroptical data show, in contrast to the parent ε,ε‐carotene, a very weak interaction between the chiral centers at C(5), C(5′), C(6), C(6′), and the polyene system. Diisobutylaluminium hydride reduction of 32 lead rather than to the expected 15,15′‐didehydro analogue 35 of Cycloviolaxanthin (8), to the polyenyne 36 (Scheme 5). We explain this reaction by an oxirane rearrangement leading to a cyclopropyl ether followed by a fragmentation to an aldehyd on the one side and an enol ether on the other (Scheme 6). This complex rearrangement includes a shift of the whole polyenyne chain from C(6), C(6′) to C(5), C(5′) of the original molecule.

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Section: Carotinoide Rnit 7-0xabicyclo[22l]heptyl-endgruppenunclassified

Section: Methyl-camphanoat ( = Methyl-477-trimethyl-3-oxo-2-oxabicymentioning

confidence: 99%

See 1 more Smart Citation

Carotinoide mit 7‐Oxabicyclo[2.2.1]heptyl‐Endgruppen. Teil I. Versuch einer Synthese von Cycloviolaxanthin (= (3S,5R,6R,3′S,5′R,6′R)‐3,6:3′,6′‐Diepoxy‐5,6,5′,6′‐tetrahydro‐β,β‐carotin‐5,5′‐diol)

Gmünder

Eugster

1990

Helvetica Chimica Acta

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“…These compounds are present in the cuticular wax of the leaf and flower and include as the major components the (4S,6R)-and (4R,6R)-diols (2) and (3) (Wahlberg & Enzell, 1987). The (7S,8S)-epoxide (1) (2), and their absolute configurations have been determined by chemical correlation with this diol (Wahlberg, Eklund, Vogt, Enzell & Berg, 1986). …”

mentioning

confidence: 99%

“…The isolation of 3.7 mg of (1) from a chloroform extract of flowers of Greek tobacco has been described previously (Wahlberg, Eklund, Vogt, Enzell & Berg, 1986). A single crystal was obtained by recrystallization from a mixture of hexane and (2) 3.58 (7) 0(2) -4414 (3) -1476 (7) - 5346 (2) 3.93 (8) 0(3) -2715 (2) -1218 (7) - 3252 (2) 4.78 (8) 0(4) -8619 (3) 2484 (7) - 5332 (2) 4.45 (8) Table 2.…”

mentioning

confidence: 99%