Plant growth regulators in Eucalyptus grandis. IV. Synthetic approaches to G-regulator analogues

1982 ◽  
Vol 35 (7) ◽  
pp. 1411 ◽  
Author(s):  
ML Bolte ◽  
WD Crow ◽  
S Yoshida
Keyword(s):  
Plant Growth ◽  
Plant Growth Regulators ◽  
Lewis Acid ◽  
Growth Regulators ◽  
Good Yield ◽  
Acid Catalysis ◽  
Physiological Activity ◽  
Eucalyptus Grandis ◽  
Synthetic Approach ◽  
Synthetic Approaches

A new synthetic approach is described to the plant growth regulators of the hexahydrobenzo[e]- 1,2-dioxin group (the G-regulators of Eucalyptus grandis). Condensation of 1,3-diketones with aldehydes under Lewis acid catalysis gives, in good yield, the 1 : 2 adducts (4H-1,3-dioxins); these are simultaneously cleaved and (with some exceptions) oxidized on silica gel to the desired structure. In this way synthesis of a number of G-regulator analogues of similar physiological activity has been achieved.

Studies on the Relation between Molecular Structure and Physiological Activity of Plant Growth-Regulators. I. Abscission-Inducing Activity

1952 ◽  
Vol 113 (3) ◽  
pp. 348-362 ◽  
Author(s):  
Robert L. Weintraub ◽  
James W. Brown ◽  
Jean C. Nickerson ◽  
Katharine N. Taylor
Keyword(s):  
Molecular Structure ◽  
Plant Growth ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Physiological Activity

Synthetic Plant Growth Regulators. IV. The Preparation of Hydroxylated Helminthosporic Acid Analogues

1979 ◽  
Vol 32 (4) ◽  
pp. 823 ◽  
Author(s):  
LN Mander ◽  
LT Palmer
Keyword(s):  
Plant Growth ◽  
Plant Growth Regulators ◽  
Lewis Acid ◽  
Growth Regulators ◽  
Sodium Borohydride ◽  
Sigmatropic Rearrangement ◽  
Hydroxyl Group ◽  
Hydroxy Ketone ◽  
Wittig Olefination ◽  
Sequential Reduction

Sequential reduction (sodium borohydride, metal-ammonia, hydrogenation) of ketone (8) gave the hydroxy ketone (9) which was converted into olefin (10) (Wittig olefination) and thence to acid (14) by means of the [2,3] sigmatropic rearrangement of ylide (12) to (13). Acid (15) was similarly prepared from alcohol (11) which was obtained by deoxygenation of ketone (9). The tetrahydrocuminic acid (16) was hydroxylated (lithium diisopropylamine, oxygen); the new hydroxyl group was protected with a dichloroacetyl function and then converted into the diazoketone. Lewis-acid-induced cyclization of (17) gave the bicyclooctanone (18a) plus its Δ3-isomer (18b), both of which were reduced and hydrolysed to hydroxy ketone (19). Wittig methylenation of (19) gave olefin (20) which was rearranged by acid to ketone (21). Both (20) and (21) were elaborated further to the acids (6) and (25), respectively, by the procedures used in the preparation of acids (14) and (15).

Plant growth regulators in Eucalyptus grandis. VI. Reaction of the G-regulators with nucleophiles

1982 ◽  
Vol 35 (7) ◽  
pp. 1431 ◽  
Author(s):  
ML Bolte ◽  
WD Crow ◽  
S Yoshida
Keyword(s):  
Plant Growth ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Eucalyptus Grandis ◽  
Michael Adducts

The formation of Michael adducts from the G-regulators and analogues with amines is described. Such adducts are, in general, unstable zwitterionic compounds and are decomposed by the action of acid into the parent G-regulator and the related 2-aminomethylene 1,3-diketone. Analogies are drawn with the natural storage and release in vivo.

Plant growth regulators in Eucalyptus grandis. V. Synthesis of the G-regulators

1982 ◽  
Vol 35 (7) ◽  
pp. 1421 ◽  
Author(s):  
ML Bolte ◽  
WD Crow ◽  
S Yoshida
Keyword(s):  
Hydrogen Bonding ◽  
Plant Growth ◽  
Growth Regulators ◽  
Mannich Reaction ◽  
Mannich Base ◽  
Eucalyptus Grandis ◽  
High Yield ◽  
Aqueous Acid ◽  
The Mannich Reaction ◽  
Synthetic Approaches

Problems associated with earlier synthetic approaches to the G-regulators have been overcome by the use of the Mannich reaction in aprotic media. Under these conditions the Mannich base formed from the reaction of 1,3-diketones and aldehydes is stabilized by internal hydrogen bonding and can be isolated in high yield. In aqueous acid rapid elimination occurs to give the 2-methylene 1,3-diketones, which first enolize then add oxygen to generate the G-regulator structure. The steric limitations of the reactions are examined.

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