Flavan derivatives. XXVI. 3(3')-Hydroxyisochromano(4',3':2,3)chromans. Mechanism of formation of these hemiketals from 1'-Oxo-isochromono-(4',3':2,3)chromones

1969 ◽  
Vol 22 (11) ◽  
pp. 2389 ◽  
Author(s):  
JW Clark-Lewis ◽  
EW Della ◽  
MM Mahandru
Keyword(s):  
Carboxylic Acids ◽  
Carbonyl Group ◽  
Lactone Ring ◽  
Direct Reduction ◽  
Hydroxyl Group ◽  
Lithium Aluminium Hydride ◽  
Mechanism Of Formation ◽  
Hydride Ion ◽  
Lithium Aluminium ◽  
Nucleophilic Displacement

Reduction of the lactones of flavonol-2?-carboxylic acids [1?- oxoisochromono-(4?,3?:2,3)chromones] to hemiacetals by lithium aluminium hydride is shown to proceed by fission of the lactone ring accompanied by direct reduction of the chromone carbonyl group without fission of the chromone ring. The intermediate chrom-2-en-4-ols undergo nucleophilic displacement of the allylic (and benzylic) hydroxyl group by hydride ion attack at the 2- and 4-positions. Reduction of 7- methoxyisochromeno(4?,3?:2,3)chromone with lithium aluminium deuteride led to 7-methoxyisochromeno(4?,3?:2,3)chromen with 95% incorporation of two deuterium atoms.

Bisquaternary ammonium salts derived from 3α,12α-Diamino-5β-cholane and 3α,12α-Diamino-24-nor-5β-cholane

1971 ◽  
Vol 24 (3) ◽  
pp. 521 ◽  
Author(s):  
S Ahmed ◽  
M Alauddin ◽  
B Caddy ◽  
M Martin-Smith ◽  
WTL Sidwell ◽  
...  
Keyword(s):  
Deoxycholic Acid ◽  
Ammonium Salts ◽  
Hydroxyl Group ◽  
Amino Compound ◽  
Hydroxyl Groups ◽  
Lithium Aluminium Hydride ◽  
Lithium Aluminium ◽  
Polyhydric Alcohols ◽  
Methane Sulphonate ◽  
Methylene Group

The preparation of 3α,12α-bisdimethylamino-5β-cholane dimethiodide, 3α,12α-bisdimethylamino-5β-cholane dimethiodide, 3α,12α- bisdimethylamino-24-nor-5β-cholanedimethiodide, and 3α,12α- bisdimethylamino-24-nor-5β-cholanediethiodide, from deoxycholic acid are described. During this work it was found that attempted copper- quinoline decarboxylation of dehydrocholic acid gives rise to lactol formation, and that what had previously been considered to be 3α,12α- dihydroxy-5β-cholane is a mixture of this compound and 12α,24- dihydroxy-5β-cholane. Comparable selectivity of attack by methanesulphonyl chloride and toluene-p-sulphonyl chloride occurs with various polyhydric alcohols derived from bile acids, as evidenced from the products of reduction of the sulphonates with lithium aluminium hydride. With both 5α- and 5β-cholane derivatives, a C 3 equatorial hydroxyl group exhibits comparable reactivity to the terminal primary hydroxyl group, generated from the bile acid carboxylic group, towards both sulphonyl chlorides. With axial hydroxyl groups at C 7 and C 12, toluene-p-sulphonate formation is much more difficult than methane- sulphonate formation. Reduction by means of lithium aluminium hydride of equatorial sulphonate esters at C 7 and C 12 gives rise to a methylene group, but the axial sulphonates under the same conditions give the axial alcohol. The same clear distinction between equatorial and axial sulphonate esters is not observed at C 3 and C 6, but 17α- methanesulphonyloxy-5α-androstane gives 5α-androstane and the 17β- ester gives 17β-hydroxy-5α-androstane. Reduction of 12-oximino groups in both 5α- and 5β-cholanes with sodium and ethanol, hydrogen in the presence of a catalyst, or lithium aluminium hydride gives solely the 12α-amino compound.

Lithium Aluminum Hydride Reductive Rearrangement of Allylic Acetals to Vinyl Ethers: A Synthesis of 3-Deoxy Glycals

1975 ◽  
Vol 53 (13) ◽  
pp. 2005-2016 ◽  
Author(s):  
Bert Fraser-Reid ◽  
Steve Y-K. Tam ◽  
Bruno Radatus
Keyword(s):  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Hydroxyl Group ◽  
Lithium Aluminum ◽  
Allylic Alcohols ◽  
Vinyl Ethers ◽  
Hydride Ion ◽  
Lithium Aluminium ◽  
Leaving Group ◽  
Ethereal Oxygen

Carbohydrate allylic acetals (hex-2-enopyranosides) are reductively rearranged to vinyl ethers (3-deoxy glycals) by treatment with lithium aluminium hydride in refluxing ethereal solvents. Under similar conditions, some allylic alcohols are also reductively rearranged to olefins, although the reaction appears to be confined to carbohydrate substrates since the reaction fails with typical carbocyclic allylic alcohols.The results are rationalized by postulating the intermediacy of an oxygen–alane complex, this being formed more readily in the case of an hydroxyl (or ester) rather than an ethereal oxygen. An axial oxygen permits easier achievement of the reactive transition state than an equatorial oxygen. The complex normally leads to an SN2' reductive rearrangement in which the entering hydride and departing oxygen are syn-related. Alternatively, and particularly when the double bond is flanked by an hydroxyl group at one allylic position and a leaving group at the other, an abnormal SN2′ process may occur so that the hydride ion is delivered vicinal and cis to the hydroxyl group, with ejection of the leaving group. The process is at all times stereospecific but not always regiospecific.

Flavan derivatives. XIII. The formation of 1,3-Diarylpropan-2-ols and 2,3-Diarylpropan-1-ols from Flavan-3-ols

1965 ◽  
Vol 18 (3) ◽  
pp. 389 ◽  
Author(s):  
JW Clark-Lewis ◽  
GC Ramsay
Keyword(s):  
Molecular Complex ◽  
Liquid Ammonia ◽  
Reduction Method ◽  
Optical Purity ◽  
Specific Rotation ◽  
Aluminium Chloride ◽  
Lithium Aluminium Hydride ◽  
Mechanism Of Formation ◽  
Lithium Aluminium ◽  
Trimethyl Ether

No change in specific rotation of (-)-1-(3,4-dimethoxyphenyl)-3-(2,4,6- trimethoxyphenyl)propan-2-ol was observed during attempted resolution, so that the propanol is probably close to optical purity in spite of its low specific rotation. (-)-Epigallocatechin pentamethyl ether was reduced with sodium and liquid ammonia to an analogous hexamethoxydiarylpropan-2-ol. Several conditions for reducing ( +)-catechin tetramethyl ether with lithium aluminium hydride-aluminium chloride mixtures were examined, and the reduction method was applied to (-)- epiafzelechin trimethyl ether and to (-)-epigallocatechin pentamethyl ether. The mechanism of formation of the (-)-2,3-diarylpropan-1-ol from (+)-catechin and (-)-epicatechin tetramethyl ethers is discussed. The 5,7,4'-trimethyl ethers of (-)-epiafzelechin and (�)-dihydrokaempferol were found to form a 1 : 1 molecular complex.

Convenient Synthesis of (Z)-7- and (E)-9-dodecene-1-yl Acetate, Components of Some Lepidoptera Insect Sex Pheromone

2017 ◽  
Vol 68 (1) ◽  
pp. 180-185
Author(s):  
Adriana Maria Andreica ◽  
Lucia Gansca ◽  
Irina Ciotlaus ◽  
Ioan Oprean
Keyword(s):  
Sex Pheromone ◽  
Coupling Reaction ◽  
Coupling Scheme ◽  
Lithium Aluminium Hydride ◽  
Terminal Alkyne ◽  
Mercury Derivative ◽  
Lithium Aluminium ◽  
Convenient Synthesis ◽  
Practical Synthesis ◽  
Insect Sex

Were developed new and practical synthesis of (Z)-7-dodecene-1-yl acetate and (E)-9-dodecene-1-yl acetate. The routes involve, as the key step, the use of the mercury derivative of the terminal-alkyne w-functionalised as intermediate. The synthesis of (Z)-7-dodecene-1-yl acetate was based on a C6+C2=C8 and C8+C4=C12 coupling scheme, starting from 1,6-hexane-diol. The first coupling reaction took place between 1-tert-butoxy-6-bromo-hexane and lithium acetylide-ethylendiamine complex obtaining 1-tert-butoxy-oct-7-yne, which is transformed in di[tert-butoxy-oct-7-yne]mercury. The mercury derivative was directly lithiated and then alkylated with 1-bromobutane obtaining 1-tert-butoxy-dodec-7-yne. After acetylation and reduction with lithium aluminium hydride of 7-dodecyne-1-yl acetate gave (Z)-7-dodecene-1-yl acetate with 96 % purity. The synthesis of (E)-9-dodecene-1-yl acetate was based on a C8+C2=C10 and C10+C2=C12 coupling scheme, starting from 1,8-octane-diol. The first coupling reaction took place between 1-tert-butoxy-8-bromo-octane and lithium acetylide-ethylendiamine complex obtaining 1-tert-butoxy-dec-9-yne, which is transformed in di[tert-butoxy-dec-9-yne]mercury. The mercury derivative was directly lithiated and then alkylated with 1-bromoethane obtaining 1-tert-butoxy-dodec-9-yne. After reduction with lithium aluminium hydride of 1-tert-butoxy-(E)-9-dodecene and acetylation was obtained (E)-9-dodecene-1-yl acetate with 97 % purity.

3-(s-Hydrindacen-4-yl)propylamines and 4-(s-hydrindacen-4-yl)butylamines; Synthesis and pharmacological screening

1981 ◽  
Vol 46 (8) ◽  
pp. 1800-1807 ◽  
Author(s):  
Zdeněk Vejdělek ◽  
Marie Bartošová ◽  
Miroslav Protiva
Keyword(s):  
Malonic Acid ◽  
Local Anaesthetics ◽  
Lithium Aluminium Hydride ◽  
Spasmolytic Activity ◽  
Lithium Aluminium ◽  
Malonic Acid Derivatives ◽  
Pharmacological Screening ◽  
Hydroxyethyl Piperazine

4-Chloromethyl-s-hydrindacene (VIIa) was transformed via the malonic acid derivatives VIIIa and IXa to the acid Xb which afforded in four steps the homological acid Xc. Reactions of chlorides of both acids (XIbc ) with dimethylamine, 1-methylpiperazine and 1-(2-hydroxyethyl)piperazine led to the amides XIIbc-XIVbc which were reduced with lithium aluminium hydride to the title compounds IVcd-VIcd. The amines obtained show central neuroleptic effects only in subtoxic doses; they are also potent local anaesthetics and have significant spasmolytic activity of the neurotropic as well as musculotropic type.

Substituted N,N-Dimethyl-3-(phenylthio)- and -4-(phenylthio)benzylamines

1992 ◽  
Vol 57 (1) ◽  
pp. 194-203 ◽  
Author(s):  
Karel Šindelář ◽  
Vojtěch Kmoníček ◽  
Marta Hrubantová ◽  
Zdeněk Polívka
Keyword(s):  
Serotonin Receptors ◽  
Hydrobromic Acid ◽  
Antidepressant Activity ◽  
Benzoic Acids ◽  
Lithium Aluminium Hydride ◽  
Acid Chlorides ◽  
Activity Inhibition ◽  
Lithium Aluminium ◽  
The Brain

(Arylthio)benzoic acids IIa - IIe and VIb - VId were transformed via the acid chlorides to the N,N-dimethylamides which were reduced either with diborane "in situ" or with lithium aluminium hydride to N,N-dimethyl-(arylthio)benzylamines Ia - Ie and Vb - Vd. Leuckart reaction of the aldehydes IX and X with dimethylformamide and formic acid afforded directly the amines Va and Ve. Demethylation of the methoxy compounds Ia and Ve with hydrobromic acid resulted in the phenolic amines If and Vf. The most interesting N,N-dimethyl-4-(phenylthio)benzylamine (Va) hydrochloride showed affinity to cholinergic and 5-HT2 serotonin receptors in the rat brain and some properties considered indicative of antidepressant activity (inhibition of serotonin re-uptake in the brain and potentiation of yohimbine toxicity in mice).

scholarly journals An efficient and practical chemo-enzymatic route to (3R,3aR,6R,6aR)-hexahydrofuro[3,2-b]furan-6-amino-3-ol (6-aminoisomannide) from renewable sources

SynOpen ◽  
2021 ◽  
Author(s):  
Valerio Zullo ◽  
Antonella Petri ◽  
Anna Iuliano
Keyword(s):  
Hydroxy Group ◽  
Sodium Azide ◽  
Hydroxyl Group ◽  
Azido Group ◽  
One Pot ◽  
Renewable Sources ◽  
Nucleophilic Displacement ◽  
Trifluoromethanesulfonic Anhydride ◽  
Enzymatic Route

The synthesis of 6-aminoisomannide is easily achieved starting from the renewable, inexpensive and commercially available isosorbide, in 66% overall yield. A biocatalysed highly regioselective acetylation of the 3-endo hydroxyl group of isosorbide was followed by the stereospecific interconversion of the 6-exo hydroxyl group into azido group, through reaction with trifluoromethanesulfonic anhydride followed by nucleophilic displacement of the triflate group by sodium azide. Finally, reduction of the azido group and deacetylation of the 3-hydroxy group were performed one pot by using LiAlH4.

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