650. Gibberellic acid. Part XXVIII. Some derivatives of gibberellins A4 and A7

Aldridge, David C.; Hanson, James R.; Mulholland, T. P. C.

doi:10.1039/jr9650003539

Cited by 22 publications

(9 citation statements)

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“…Synthesis of GA 5 and 1,2-didehydro GA2o was as described by Evans et al (1990), GA~ and GA 4 by Bell and Turner (1981), the 3~-hydroxy epimer of GA~ by Cross et al (1961), the 3~-hydroxy epimer ofGA 3 by Zelinsky (1977) and the 3ct-hydroxy epimer of GA4 by Aldridge et al (1965). 2,2-Dimethyl GA 4 and its 3et-hydroxy epimer were prepared by the method of Beale and MacMillan (198l).…”

Section: Methodsmentioning

confidence: 99%

The relative significance for stem elongation and flowering in Lolium temulentum of 3?-hydroxylation of gibberellins

Evans

King

Mander

et al. 1993

Planta

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Abstract.In previous experiments with many gibberellins (GAs) and GA derivatives applied to Lolium temulentum L., quite different structural requirements were evident for stem elongation on the one hand and for the promotion of flowering on the other. Whereas hydroxylation at carbons 12, 13 and 15 enhanced flowering relative to stem growth, the reverse was the case at carbon 3 (L.T. Evans et al. 1990, Planta 182, 97-106). The significance of hydroxylation at carbon 3 is examined in this paper. The application of inhibitors of 3[3-hydroxylation, including C/D-ring-rearranged GAs, reduced stem growth but, in the case of the two acylcyclohexanediones, increased the flowering response when applied on the inductive long day. Later applications of the acylcyclohexanediones, made after floral initiation had occurred, were inhibitory to flowering, suggesting that subsequent inflorescence development requires 313-hydroxylated GAs. Applications of the 3~-hydroxy epimers of GA 1, GA 3 and GA 4 gave slightly less promotion of flowering in comparison with the 313-hydroxy GAs, but far less promotion of stem elongation, except in the case of 3-epi-GA 4, which was comparable to GA 4. The 3~-hydroxy epimer of 2,2-dimethyl GA 4 gave less promotion of flowering than its 313-hydroxy epimer but almost no promotion of stem elongation. The 3~-hydroxy epimers of GA 3 and 2,2-dimethyl GA 4 did not act as competitive inhibitors of the stem elongation elicited by GA 3 and 2,2-dimethyl GA4, respectively. These results extend the differences in GA structure which favour flowering as opposed to stem elongation, and indicate that 3-hydroxylation and its epimeric configuration are of much greater importance to stem elongation than to flower initiation in Lolium.

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Section: Methodsmentioning

confidence: 99%

The relative significance for stem elongation and flowering in Lolium temulentum of 3?-hydroxylation of gibberellins

Evans

King

Mander

et al. 1993

Planta

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“…but not in p-dioxan. 45 Similar oxidations of steroid 5-en-3/1-0Is in refluxing benzene produce 4,6-dienones,46 whereas, in dimethylformamide or pyridine at room temperature. the products are 4-en-3-ones.…”

Section: Effects Of Solvent On Oxidationmentioning

confidence: 95%

“…Based on the favored oxidation of the allylic hydroxy group by the reagent. the correct structures were assigned to the natural alkaloids buphanamine (47) and epibuphanamine (45). Thus.…”

Section: 42a Oxidation Of An Active Methylene Group Inmentioning

confidence: 99%

The Oxidation of Organic Compounds by Active Manganese Dioxide

Fatiadi

1986

Organic Syntheses by Oxidation With Metal Compounds

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“…9 Careful separation of the hydrogenolysis acids revealed the formation of 1(10)-and 9(10)-alkenes (6), which then underwent further hydrogenation to give the ring A/B cis-fused fully hydrogenated acids (7). 10 The 13-desoxy relative, gibberellin A 7 methyl ester (5, R 1 = OH, R 2 = H) with the same ring A structure, behaved similarly, 11,12 while catalytic hydrogenation of the alkaline isomerisation product (8) gave mainly hydrogenolysis acids. 13 Selectivity in the reduction of the 1,2-double bond of gibberellic acid and its 13-desoxy relative, in which the 16,17-double bond was untouched, could be achieved by carrying out the hydrogenation over palladium on barium carbonate in the presence of pyridine.…”

Section: Catalytic Reductionmentioning

confidence: 99%