PITHECOLOBINE, THE ALKALOID OF PITHECOLOBIUMSAMAN BENTH. I

1952 ◽  
Vol 30 (10) ◽  
pp. 761-772 ◽  
Author(s):  
K. Wiesner ◽  
D. M. MacDonald ◽  
Z. Valenta ◽  
R. Armstrong
Keyword(s):  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Ultraviolet Spectrum ◽  
Hydroxyl Group ◽  
Lithium Aluminum ◽  
Amino Groups ◽  
Saturated Compound ◽  
Secondary Amino ◽  
Trimethyl Amine ◽  
Methylene Group

Pithecolobine, C22H46N4O2, has a lactam group, one primary and two secondary amino groups, and a hydroxyl group. Lithium aluminum hydride converts it into a monocyclic saturated compound, desoxypithecolobine, C22H48N4. Hofmann degradation of this compound gives tetramethylputrescine, trimethyl amine, a doubly unsaturated base C16H31N with a terminal methylene group, and a base C16H34N2. Heating with selenium yields a hydrocarbon, C12;H24–26, with a sequence of six or more CH2 groups. A crystalline oxygen-free compound with two nitrogens (m.p.94 °C.) is also obtained, the ultraviolet spectrum of which is almost identical with aminopyridine.

THE REACTION OF DIETHYL AZODICARBOXYLATE WITH DIHYDROGELSEMINE

1955 ◽  
Vol 33 (4) ◽  
pp. 604-609 ◽  
Author(s):  
Thelma Habgood ◽  
Léo Marion
Keyword(s):  
Infrared Spectrum ◽  
Methyl Ether ◽  
Sodium Borohydride ◽  
Lithium Aluminum Hydride ◽  
Chromic Acid ◽  
Aluminum Hydride ◽  
Membered Ring ◽  
Lithium Aluminum ◽  
Diethyl Azodicarboxylate ◽  
Methylene Group

Dihydrogelsemine reacts with diethyl azodicarboxylate yielding a carbinolamine which forms a methyl ether. Both this ether and the carbinolamine base can be oxidized by chromic acid to the same neutral lactam. That there has been no rearrangement of the carbon skeleton during these reactions is shown by reduction of the methyl ether of the carbinolamine with sodium borohydride to dihydrogelsemine and by reduction of the lactam with lithium aluminum hydride to tetrahydrodesoxygelsemine. It is concluded that both dihydrogelsemine and gelsemine contain a methylene group adjacent to N(b), and from the infrared spectrum of the lactam of dihydrogelsemine, N(b) appears to be part of a five-membered ring.

GELSEMINE: III. REDUCTION WITH LITHIUM ALUMINUM HYDRIDE

1951 ◽  
Vol 29 (1) ◽  
pp. 37-45 ◽  
Author(s):  
Morris Kates ◽  
Léo Marion
Keyword(s):  
Absorption Spectrum ◽  
Infrared Absorption ◽  
Lithium Aluminum Hydride ◽  
Infrared Absorption Spectrum ◽  
Secondary Alcohol ◽  
Aluminum Hydride ◽  
Lithium Aluminum ◽  
Basic Nitrogen ◽  
Group Reduction ◽  
Methylene Group

The infrared absorption spectrum of gelsemine indicates the presence of a carbonyl group. Reduction of the alkaloid with lithium aluminum hydride converts the carbonyl not to a secondary alcohol, but to a methylene group, thus indicating that the carbonyl is present in a lactamic grouping. The reduced base shows the properties of a substituted aniline. Since gelsemine has been shown to yield 3-ethylindole on dehydrogenation with selenium and since the N-atom involved in the lactamic group cannot be the strongly basic nitrogen, gelsemine must contain an oxindole grouping. Furthermore, 3-monosubstituted oxindoles are converted by lithium aluminum hydride to 3-substituted indoles, whereas gelsemine under the same conditions gives rise to a dihydroindole. Therefore, the alkaloid must contain a 3, 3-disubstituted oxindole grouping.

THE PAPILIONACEOUS ALKALOIDS: XIX. THE STRUCTURE OF LUPANOLINE

1953 ◽  
Vol 31 (2) ◽  
pp. 187-192 ◽  
Author(s):  
Barry P. Moore ◽  
Léo Marion
Keyword(s):  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Hydroxyl Group ◽  
Lithium Aluminum ◽  
Direct Oxidation

Lupanoline which contains both a carbonyl and a hydroxyl group was reduced by lithium aluminum hydride to β-isosparteine. The identity of β-isosparteine was established by its conversion into sparteine by dehydrogenation and subsequent rehydrogenation. Attempts to acylate lupanoline resulted in the formation of anhydrolupanoline which was hydrogenated to dihydroanhydrolupanoline, a compound also obtained by the direct oxidation of β-isosparteine.It is concluded that lupanoline is 2-hydroxy-17-oxo-β-isosparteine.

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.

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