Insect Moulting Hormones. LV. Experiments Directed Towards the Synthesis of Non-steroidal Ecdysone Analogues

1985 ◽  
Vol 38 (3) ◽  
pp. 475 ◽  
Author(s):  
R Bergamasco ◽  
DHS Horn ◽  
RH Nearn ◽  
JS Wilkie
Keyword(s):  
Efficient Method ◽  
Boron Trifluoride ◽  
Model Compound ◽  
Boron Trifluoride Etherate ◽  
Side Chain ◽  
Mercuric Oxide ◽  
Moulting Hormones

Exploratory studies aimed at the synthesis of the non-steroidal ecdysone analogue (4aR,7S,8aR,-1′RS,4′R)-7-hydroxy-3-(1′-hydroxy-4′,8′- dimethylnonyl )-4a-methyl-4a,5,6,7,8,8a-hexahydronaphthal-en- 1(4H)-one (3) have led to in efficient method of joining the cyclic and side-chain synthons by reacting the vinylogous ester (4a) with 1-lithio-4,8-dimethyl-1,1-bis( methylthio ) nonane (12) to yield (4′RS)-3- [4′,8′-dimethyl-1′,1′-bis( methylthio ) nonyl ]-5,5-dimethylcyclohex-2-en-1-one (13). This thioacetal on reaction with boron trifluoride etherate and mercuric oxide afforded, quantitatively, the diketone (4′RS)-3-(4′,8′-dimethyl-1′-oxononyl)-5,5-dimethylcyclohex-2-en-1-one (14) which was selectively reduced in 85% yield to the required model compound (4′RS)-3-(1′-hydroxy-4′,8′-dimethylnonyl)-5,5-dimethylcyclohex-2-en-1-one (15).

Steroids. VI. Reaction of 24,28-epoxides of sterol side chain with boron trifluoride etherate

1973 ◽  
Vol 38 (9) ◽  
pp. 1688-1691 ◽  
Author(s):  
Hiroshi Ohtaka ◽  
Masuo Morisaki ◽  
Nobuo Ikekawa
Keyword(s):  
Boron Trifluoride ◽  
Boron Trifluoride Etherate ◽  
Side Chain

Experiments Directed Towards the Synthesis of Anthracyclinones. XXIX. Fluoro-Substituted Tetracycles

1996 ◽  
Vol 49 (7) ◽  
pp. 751 ◽  
Author(s):  
RC Cambie ◽  
KC Higgs ◽  
JJ Rustenhoven ◽  
PS Rutledge
Keyword(s):  
Acetic Acid ◽  
Boron Trifluoride ◽  
Reaction Times ◽  
Chair Conformation ◽  
Boron Trifluoride Etherate ◽  
Side Chain ◽  
Equatorial Position ◽  
Acid Complex ◽  
Slow Reaction

Diastereoselective formation of 9-fluoro-9-methylanthracyclinones has been achieved by treating ortho-methallyl-substituted anthraquinonyl homochiral dioxans with boron trifluoride etherate . The demethoxy anthraquinonyl dioxan (16) underwent slow reaction to give exclusively the (7S,9R) fluoro tetracycle (21) in 58% yield. The dimethoxy anthraquinonyl dioxan (15) was less reactive, allowing other reactions to compete, but boron trifluoride -acetic acid complex effected rapid cyclization of (15) with high diastereoselectivity. Short reaction times with this reagent circumvented the formation of the alkenes (25) and the naphthacenedione (9). Boron trifluoride-nitromethane gave the (7S,9R) fluoro tetracycle (19) in 36% yield. Although the yields of the fluoro tetracycles were modest, they compare favourably with a 4% yield reported for the fluorination of daunomycinone. The 6-demethoxy tetracycle (21) has been shown to exist in the expected half-chair conformation, with the bulky C7 side chain in a pseudo-equatorial position. In contrast, the 6,11-dimethoxy fluoro tetracycle (19) exists in a significantly perturbed half-chair conformation with a pseudo-axial side chain.

Synthesis of o-isopentenylphenols

1971 ◽  
Vol 24 (11) ◽  
pp. 2355 ◽  
Author(s):  
J Hlubucek ◽  
E Ritchie ◽  
WC Taylor
Keyword(s):  
Phosphoric Acid ◽  
Zinc Chloride ◽  
Boron Trifluoride ◽  
Boron Trifluoride Etherate ◽  
Stannic Chloride ◽  
Counter Ion

The effect of the solvent and the counter-ion on the ring alkylation of 3- and 4-methoxyphenols by isopentenyl bromide has been examined. Under strictly anhydrous conditions good and consistent yields of the o- isopentenylphenols were obtained with the combination potassium- toluene, but sodium-toluene was more convenient. ��� Boron trifluoride etherate was more satisfactory than stannic chloride, zinc chloride, or phosphoric acid in catalysing the condensation of 3- and 4-methoxy-phenols with 2-methylbut-3-en-2-ol to the corresponding o-isopentenylphenols. Aryl α,α-dimethylpropargyl ethers were partially hydrogenated to the corresponding α,α- dimethylallyl ethers which rearranged in boiling N,N-diethyl-aniline to o-isopentenylphenols in high overall yield.

scholarly journals Synthesis of 5,6,7,8-Tetrahydroquinolines by Thermolysis of Oxime O-Allyl Ethers in the Presence of Boron Trifluoride Etherate.

1993 ◽  
Vol 41 (7) ◽  
pp. 1297-1298 ◽  
Author(s):  
Junko KOYAMA ◽  
Tamaki OGURA ◽  
Kiyoshi TAGAHARA ◽  
Masaaki MIYASHITA ◽  
Hiroshi IRIE
Keyword(s):  
Boron Trifluoride ◽  
Boron Trifluoride Etherate ◽  
Allyl Ethers

Syntheses of the alkali metal borodeuterides

1967 ◽  
Vol 45 (21) ◽  
pp. 2583-2588 ◽  
Author(s):  
J. G. Atkinson ◽  
D. W. MacDonald ◽  
R. S. Stuart ◽  
P. H. Tremaine
Keyword(s):  
Sodium Methoxide ◽  
Boron Trifluoride ◽  
Deuterium Oxide ◽  
Secondary Alcohol ◽  
Boron Trifluoride Etherate ◽  
Residual Hydrogen ◽  
Lithium Deuteride ◽  
Chemical Purity ◽  
Molar Scale ◽  
Sodium Borodeuteride

A synthesis of sodium borodeuteride on a molar scale has been developed. Trimethylamineborane was exchanged (6) with deuteriosulfuric acid in deuterium oxide to obtain trimethylamineborane-d3 of a high isotopic purity. Reaction of trimethylamineborane-d3 with sodium methoxide in diglyme at 120–150 °C yielded sodium borodeuteride, which, after purification, was obtained in a 40–50% overall yield. The conditions for obtaining material of a high isotopic and chemical purity were found to be rather stringent but, once worked out, were easily reproducible.Lithium borodeuteride and potassium borodeuteride were also prepared from trimethylamineborane-d3 and the corresponding methoxide salts. An alternative synthesis of lithium borodeuteride, involving the reaction between lithium deuteride and boron trifluoride etherate, was found to be more satisfactory, since it avoided the formation of stable 1:1 solvent complexes with lithium borodeuteride.The products that were obtained had a chemical purity of 97%, and contained 98–99 atom % deuterium. The deuterium analyses were performed by reducing a series of ketones containing no α hydrogens and analyzing the secondary alcohol by nuclear magnetic resonance for residual hydrogen on the alcohol carbon.

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