Synthetic approaches to isobutylamides of insecticidal interest

Crombie, Leslie; Horsham, Mark A.; Blade, R. J.

doi:10.1016/s0040-4039(00)96650-4

Cited by 33 publications

(8 citation statements)

References 8 publications

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“…Previous phytochemical studies have investigated the local anesthetic and saliva-producing (sialogogic) properties of the Piper species and piperovatine, an extract isolated from Piper (Price and Pinder, 1970;Costa and Mors, 1981;Giesbrecht et al, 1981;Pring, 1982;Makapugay et al, 1983). Insecticidal isobutylamides isolated from Piper species have been synthesized (Crombie et al, 1987), and previous studies have suggested that extracts and single constituents of Piper nigrum and Piper methysticum possess inhibitory properties that are specific to cyclooxygenase-1, an important enzyme in the formation of prostaglandins, which in turn are important mediators of the development of inflammatory diseases (Gleitz et al, 1997;Venkateshwarlu, 1997). Other species of Piper act as in vitro inhibitors not only of cyclooxygenase-1 but also of 5-lipooxygenase, which is responsible for the formation of pro-inflammatory leukotrienes that play an important role in leukocyte migration (Smith, 1996).…”

Section: Introductionmentioning

confidence: 99%

Anti-inflammatory activity of the extract, fractions and amides from the leaves of Piper ovatum Vahl (Piperaceae)

Silva

Baroni

Svidzinski

et al. 2008

Journal of Ethnopharmacology

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Section: Introductionmentioning

confidence: 99%

Anti-inflammatory activity of the extract, fractions and amides from the leaves of Piper ovatum Vahl (Piperaceae)

Silva

Baroni

Svidzinski

et al. 2008

Journal of Ethnopharmacology

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“…of tetrabutylammonium fluoride at 23 "C gave only traces of the expected hydroxy ester 17 and no recovered starting material.I7 Other protecting groups were therefore examined. Each was subjected to hydrozirconation as before, and the resulting vinylzirconocenes were coupled with bromo ester 13 in the presence of Pdo catalyst to give the products 18 (42%) and 19 (41%), some premature deprotection being noted.…”

mentioning

confidence: 99%

Syntheses of the ethyl esters of the plant host-selective (H-S) toxins (AF-IIa, AF-IIc and AK-II) produced by pathotypes of Alternaria alternata

Crombie¹,

Horsham²,

Jarrett³

1991

J. Chem. Soc., Perkin Trans. 1

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Total syntheses of the ethyl esters of the host-selective (H-S) toxins produced b y Alternaria alternata (strawberry-type pathogen), AF-lla and AF-llc, and b y the Japanese pear-type AK-II are reported. The initial synthetic objectives, the 2€,4€,6€, 2€,4Z,6€ and 2€,4€,6Z stereoisomers of ethyl 8hydroxy-9-met hyldeca -2,4,6,9tetraenoate, were attained by the use of acetylene hydrometal lation and Pdo-mediated vinyl halide coupling: for this purpose tin chemistry was superior to the use of zirconium compounds. The tetraene-hydroxy esters were epoxidised selectively at the 9,lO-dou ble bond b y the Sharpless procedure under conditions of kinetic control (50% reaction), which it was predicted would lead to products of predominantly (8R,9S) -stereochemistry. Esterification of the epoxides produced from the 2€,4€,6€ and 2€,4€,6Z hydroxy esters w i t h synthetic (2R,3S) -2-(tbutyldimethylsiloxy) -3-methylpentanoic acid, followed by H PLC separation, gave as the major products, stereoisomers which, after deprotection, were characterised as the ethyl esters AF-toxin I Ic and AF-toxin lla. The stereochemical nature of the minor products in the epoxidations is considered. For the synthesis of the AK-I I toxin as its ethyl ester, similar esterification w i t h N-acetyl-L-phenylalanine was carried out, except that racemisation of the amino acid centre ensued. This led to two major products which were separated and identified as (8R,9Sr2'S) -and ( 8Rr9S,2'R) -stereoisomers, the former being identical with the ester of AK-II toxin.* Added in prooJ: AF-I and AF-111 toxins have E / Z patterns similar to AF-I1 toxins but with the 2'-hydroxy esterified with 2,3-dihydroxy-3methylbutyric acid and 2-hydroxy-3-methylbutyric acid respectively.8b

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“…Strong bases are known to induce the isomerization of allenes to terminal alkynes. [41][42][43] Moreover, following isomerization, the acetylide would be generated in situ and add directly to the aldehyde to afford the nine-membered ring 29. We screened several reaction conditions trying different Lewis acids, bases, reaction temperatures, and times (Table 2), however, all conditions evaluated did not provide the desired product 29.…”

Section: Scheme 8 Preparation Of Aldehyde 19mentioning

confidence: 99%

Synthetic Studies on the Sporolides: Exploration of the Enediyne Route

Bonazzi¹,

Binaghi²,

Fellay³

et al. 2009

Synthesis

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Synthetic studies towards the construction of the cyclopenta[a]indene fragment of the heptacyclic marine metabolite sporolide are reported based on a hypothetical biosynthesis. The key step of this biogenetic proposal includes a Bergman cyclization of an enediyne precursor. The enediyne target of this synthetic study was prepared by Sonogashira cross-coupling of two fragments, of which the cyclopentane fragment was prepared from cyclopentenone, Morita-Baylis-Hillman reaction, and enantioselective Sharpless dihydroxylation.

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Synthetic approaches to isobutylamides of insecticidal interest

Cited by 33 publications

References 8 publications

Anti-inflammatory activity of the extract, fractions and amides from the leaves of Piper ovatum Vahl (Piperaceae)

Anti-inflammatory activity of the extract, fractions and amides from the leaves of Piper ovatum Vahl (Piperaceae)

Syntheses of the ethyl esters of the plant host-selective (H-S) toxins (AF-IIa, AF-IIc and AK-II) produced by pathotypes of Alternaria alternata

Synthetic Studies on the Sporolides: Exploration of the Enediyne Route

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