Pyrrolylpolyenes. Part 2. Stereochemistry of Wallemia A and synthesis of its (E)-isomer and other models

Badar, Yasmeen; Chopra, Akash K.; Dias, Hanwellage W.; Hursthouse, Michael B.; Khokhar, Abdul R.; Ito, Masayoshi; Toube, T. P.; Weedon, B. C. L.

doi:10.1039/p19770001372

Cited by 13 publications

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“…The following research 64,65 has expanded the range of obtainable enediones (Scheme 26). An analogous reaction conducted by Badar et al 66 led to the formation of enedione 2 containing a pyrrole fragment (R 1 = i-Pr, R 3 = 2-pyrrolyl) in a low unspecified yield.…”

Section: Synthesismentioning

confidence: 90%

Hemicurcuminoids (1-styryl-1,3-diketones) – valuable multi-faceted building blocks for organic synthesis

et al. 2023

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Section: Synthesismentioning

confidence: 90%

Hemicurcuminoids (1-styryl-1,3-diketones) – valuable multi-faceted building blocks for organic synthesis

et al. 2023

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“…film) 2 963, 1 675, 1 585, and 1 096 cm-l; 6 0.92 (t, J 7 Hz, 3 H), 1.17 (s, 9 H), 1.2-1.5 (m, 4 H), 2.70 (t, J 7 Hz, 2 H), 2.64 (s, 3 H), and 2.62 (s, 1 H); m / z 198 (M"; Calc. for C12H2,02: m/z 198, lo), 166 ( M -31, 5), 151 ( M -31 -15, 5), 141 ( M -57, loo), and 57 (8). (18).-Substitution of ethanol for methanol in the previous experiment gave the enol ether (2.2 g); h,,,.…”

Section: 26-trimet/~y1-6-piualoyloxyoct-7-en-4-yn-3-olmentioning

confidence: 93%

Carotenoids and related compounds. Part 40. Synthesis of trikentriorhodin and other β-diketones

Chopra¹,

Moss²,

Weedon³

1988

J. Chem. Soc., Perkin Trans. 1

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Three routes to polyene 0-diketones are described.Condensation of 8'-apo-P-carotenal (4) and of 8,8 '-diapo-carotene-8,8'-dial (6) with butylamine in the presence of tri-isobutyl borate gave the Schiff's bases (5) and ( 7 ) respectively. These reacted with the boric oxide complex of acetylacetone t o give the polyene B-diketones (8) and ( 9).Reaction of the di-lithium salt of 3-methylpent-I -en-4-yn-3-01 (32) with pivalic anhydride (1 1 ) yielded the acetylenic ketone (34)' which on hydration furnished the P-diketone (36). This was converted into the Wittig salt (39) which condensed with the trienedial (44) t o give the polyene pdiketones ( 45) and ( 46).Polyene carboxylic esters were found t o condense with methyl ketones, in the presence of lithamide, t o give P-diketones in high yield. Thus methyl 8'-apo-~-carotenoate (59)' for which a synthesis from ( 44) is reported, condensed with the trimethylsilyl derivative of the optically active hydroxy-ketone (64) t o give, after hydrolysis of the protecting group, trikentriorhodin (1). Comparison of the c.d. properties of the synthetic compound, w i t h those reported for the natural pigment, indicate that the latter has the 3S, 5R configuration.

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“…(ethanol) 365 nm; v,,,. (KBr) 3 320, 1 690, 1 625, and 995 cm-'; 6, (80MHz) 1.30(3H,t, J7Hz),4.20(2H,q,J7Hz),5.88(1 H , d , J 15 Hz), 6.25 (1 H, m), 6.43 (2 H, m and dd, J 10 and 15 Hz), 6 (3).-To a stirred solution of the ester (2) (20 mg, 0.1 1 mmol) in dry ether (10 cm3) at -70 "C a solution was added of di-isobutylaluminium hydride in hexane (20%; 1 cm3). The mixture was stirred at -70 "C for 30 min and methanol (10 cm3) then added.…”

Section: Methodsmentioning

confidence: 99%

“…Reduction of pyrrolylpolyene esters such as (1) with lithium aluminium hydride yields the corresponding allylic alcohols, but these are highly unstable under the reaction condition^. '^^ Reduction of (1) using di-isobutylaluminium hydride, however, permitted the isolation of the alcohol (3) in reasonable yield.…”

mentioning

confidence: 99%

Pyrrolylpolyenes. Part 6. Synthesis of wallemia A and wallemia E

Ahmed¹,

Toube²

1984

J. Chem. Soc., Perkin Trans. 1

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The pigments (4€,6€,8€, 1 O € ) -2,6-dimethyl-5hydroxy-1 1pyrrol-2-ylu ndeca -4,6,8,10-tetraen -3one (wallemia A) and (4€,6€,8€,1 0E)-I 1 -(3-chloropyrrol-2-yl)-2,6-dimethyl-5-hydroxyundeca-4,6,8,10-tetraen-3-one (wallemia E), identical with the compounds extracted from the fungus Wallemia sebi, have been synthesised. Analogous p-enamino ketones were by-products of the synthesis.In Part 5 we reported revised structures for the pyrrolylpolyene pigments isolated ' from the fungus WaZZemia sebi (Fr.) v. Arx.The syntheses of two of the principal pigments, wallemia A (7) and wallemia E (12), have now been carried out following routes established in our earlier syntheses of pyrrolylpolyene P-diketones.Reduction of pyrrolylpolyene esters such as (1) with lithium aluminium hydride yields the corresponding allylic alcohols, but these are highly unstable under the reaction condition^.'^^ Reduction of (1) using di-isobutylaluminium hydride, however, permitted the isolation of the alcohol (3) in reasonable yield.

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Pyrrolylpolyenes. Part 2. Stereochemistry of Wallemia A and synthesis of its (E)-isomer and other models

Cited by 13 publications

References 0 publications

Hemicurcuminoids (1-styryl-1,3-diketones) – valuable multi-faceted building blocks for organic synthesis

Hemicurcuminoids (1-styryl-1,3-diketones) – valuable multi-faceted building blocks for organic synthesis

Carotenoids and related compounds. Part 40. Synthesis of trikentriorhodin and other β-diketones

Pyrrolylpolyenes. Part 6. Synthesis of wallemia A and wallemia E

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