BIOCHEMISTRY OF THE USTILAGINALES: VIII. THE STRUCTURES AND CONFIGURATIONS OF THE USTILIC ACIDS

1953 ◽  
Vol 31 (4) ◽  
pp. 396-417 ◽  
Author(s):  
R. U. Lemieux
Keyword(s):  
Methyl Esters ◽  
Active Form ◽  
Aluminum Hydride ◽  
Optically Active ◽  
Lithium Aluminum ◽  
Acid Oxidation ◽  
Chromic Acid Oxidation ◽  
Pure Compounds ◽  
Hydrolysis Of ◽  
Derivatives Of

Methanolysis of ustilagic acid and hydrolysis of the methyl esters formed yielded a crystalline acidic fraction which was essentially a mixture of two substances termed the ustilic acids A and B. The acids were separated as their iso-propylidene derivatives. The ustilic acids cocrystallize to mixtures with melting points intermediate between those of the pure compounds. Conversion of ustilic acid A, m.p. 112–113 °C, [α]D −8° in methanol, which made up about 70% of the mixture, by hydrogenolysis to palmitic acid, by oxidation with chromic oxide to pentadecanedioic acid, and by lead tetraacetate oxidation followed by hydrogenation to 15-hydroxypentadecanoic acid showed the substance to be an optically active form of 15,16-dihydroxyhexadecanoic acid. Conversion of ustilic acid B, m.p. 140–141 °C, [α]D−10° in methanol, by sodium bismuthate oxidation followed by hydrogenation to 1,14-dihydroxytetradecane, by chromic acid oxidation of its methyl ester followed by hydrolysis of the product, and peroxide oxidation of the α-keto acid thus formed to tetradecanedioic acid, and by hydrogenolysis of the C2-carbon atom through a series of reactions to ustilic acid A, showed the substance to be an optically active form of 2,15,16-trihydroxy-hexadecanoic acid. Optically active forms of 2,15-dihydroxypentadecanoic and 2-hydroxypentadecanoic acids were prepared from ustilic acid B. Application of certain empirical rules of rotation to derivatives of these 2-hydroxyacids showed them to possess the D-configuration. Reduction of ustilic acid B with lithium aluminum hydride gave meso-1,2,15,16-tetrahydroxyhexadecane. Thus, ustilic acid B was the 2D,15D,16-trihydroxyhexadecanoic acid and the ustilic acid A was the 15D,16-dihydroxyhexadecanoic acid. Several derivatives of the above described acids were prepared.

DERIVATIVES OF DEHYDROABIETIC AND PODOCARPIC ACIDS

1963 ◽  
Vol 41 (8) ◽  
pp. 1924-1936 ◽  
Author(s):  
Ernest Wenkert ◽  
Peter Beak ◽  
Richard W. J. Carney ◽  
James W. Chamberlin ◽  
David B. R. Johnston ◽  
...  
Keyword(s):  
Methyl Esters ◽  
Resin Acid ◽  
Aluminum Hydride ◽  
Resin Acids ◽  
Lithium Aluminum ◽  
Hydride Reduction ◽  
Rate Of Hydrolysis ◽  
Keto Derivative ◽  
Hydrolysis Of ◽  
Derivatives Of

The lithium aluminum hydride reduction of nitriles in the aromatic resin acid series to aldimines and the conversion of the products to other derivatives are described. The effect of the stereochemistry of the nitriles on the rate of reduction is noted. The transformation of dehydroabietane into a dehydro product is indicated. The syntheses of a desoxydecarboxy-5,6-dehydro-7-keto derivative of podocarpic acid and its optical antipode are discussed. The stereochemistry of hydrogenation of 5,6-dehydro derivatives of podocarpic acid is reported. The effect of a 7-keto group on the rate of hydrolysis of methyl esters of aromatic resin acids is illustrated. The reactions of 6-bromo-7-keto derivatives of methyl podocarpate with bases are portrayed.

scholarly journals Novel Amino Acid Derivatives of Quinolines as Potential Antibacterial and Fluorophore Agents

2020 ◽  
Vol 88 (4) ◽  
pp. 57
Author(s):  
Oussama Moussaoui ◽  
Rajendra Bhadane ◽  
Riham Sghyar ◽  
El Mestafa El Hadrami ◽  
Soukaina El Amrani ◽  
...  
Keyword(s):  
Amino Acid ◽  
Methyl Esters ◽  
Amino Acid Derivatives ◽  
Bacterial Strains ◽  
Fluorescent Properties ◽  
Topoisomerase Iv ◽  
Microdilution Method ◽  
Hydrolysis Of ◽  
Derivatives Of

A new series of amino acid derivatives of quinolines was synthesized through the hydrolysis of amino acid methyl esters of quinoline carboxamides with alkali hydroxide. The compounds were purified on silica gel by column chromatography and further characterized by TLC, NMR and ESI-TOF mass spectrometry. All compounds were screened for in vitro antimicrobial activity against different bacterial strains using the microdilution method. Most of the synthesized amino acid-quinolines show more potent or equipotent inhibitory action against the tested bacteria than their correspond esters. In addition, many of them exhibit fluorescent properties and could possibly be utilized as fluorophores. Molecular docking and simulation studies of the compounds at putative bacterial target enzymes suggest that the antimicrobial potency of these synthesized analogues could be due to enzyme inhibition via their favorable binding at the fluoroquinolone binding site at the GyrA subunit of DNA gyrase and/or the ParC subunit of topoisomerase-IV.

PSEUDACONITINE, AND THE STEREOCHEMICAL RELATIONSHIP OF THE HIGHLY OXYGENATED ACONITE ALKALOIDS

1963 ◽  
Vol 41 (6) ◽  
pp. 1485-1489 ◽  
Author(s):  
Y. Tsuda ◽  
Léo Marion
Keyword(s):  
Acetic Acid ◽  
Absolute Configuration ◽  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Reduction Product ◽  
Lithium Aluminum ◽  
Partial Hydrolysis ◽  
Previous Knowledge ◽  
Relationship Of ◽  
Hydrolysis Of

An alkaloid isolated from Aconitum spicatum Stapf has been found to be identical not only with the originally described pseudaconitine but also with 'α-pseudaconitine'. The product of the partial hydrolysis of the base, i.e., veratroylpseudaconine, is dextrorotatory, and not laevorotatory as recorded in the old literature. On heating, pseudaconitine undergoes pyrolysis, loses the elements of acetic acid, and gives rise to pyropseudaconitine. This substance, on treatment with lithium aluminum hydride, is converted to demethoxyisopyropseudaconine which is identical with the Wolff–Kishner reduction product of pyraconine. This correlation establishes that pseudaconitine and aconitine possess the same absolute configuration, which, in the light of previous knowledge, is extended also to indaconitine, delphinine, mesaconitine, and jesaconitine.

scholarly journals Hydroxyderivatives of levoglucosenone in reactions of enantioselective reduction of 1,3-diphenylpropan-1-one

2020 ◽  
Vol 63 (9) ◽  
pp. 19-25
Author(s):  
Anna N. Davydova ◽  
◽  
Bulat T. Sharipov ◽  
Farid A. Valeev ◽  
◽  
...  
Keyword(s):  
Aluminum Hydride ◽  
Point Of View ◽  
Chiral Ligands ◽  
Lithium Aluminum ◽  
Hydrogen Atoms ◽  
Enantioselective Reduction ◽  
Urgent Task ◽  
Partial Neutralization ◽  
Prochiral Ketones ◽  
Derivatives Of

The enantioselective reduction of prochiral ketones is an important method for the preparation of enanti-enriched secondary alcohols, which can serve as starting materials for optically active compounds. Chiral metal hydride reagents, such as lithium aluminum hydride (LiAlH4) and sodium borohydride (NaBH4), modified with chiral ligands, have been developed to effect enantioselective reduction. However, in most cases, derivatives are used to obtain chiral hydride reagents, which are rare and hardly available. Therefore, the search for more accessible and effective derivatives suitable for the modification of hydride reagents is an urgent task. Levoglucosenone is an optically pure enone of carbohydrate nature, readily available by pyrolysis of any cellulose-containing materials. Levoglucosenone is considered a promising bioplatform for both laboratory synthesis and industrial use. The prospect of the development of chemistry of levoglucosenone and its derivatives in industry makes it possible to pay attention to these compounds from the point of view of studying their possibilities as chiral inducers or auxiliaries. In this work, we studied the possibilities of chiral induction in the reduction reactions of 1,3-diphenylpropan-1-one with hydride reagents obtained by replacing hydrogens in LiAlH4 and NaBH4 with hydroxy derivatives of levoglucosenone. The reduction of 1,3-diphenylpropan-1-one with chiral aluminum hydride reagents proceeded with low enantioselectivity, mainly with a predominance of (S)-1,3-diphenylpropan-1-ol. It was found that the enantiomeric purity of the S-stereomer decreases with an increase in the substitution of hydrogen atoms in LiAlH4 by hydroxy derivatives of levoglucosenone. Reduction of 1,3-diphenylpropan-1-one with reagents obtained by partial neutralization of NaBH4 with hydroxy derivatives of levoglucosenone, on the contrary, predominantly leads to the formation of (R)-1,3-diphenylpropan-1-ol. The addition of AcOH and Bu4NCl to NaBH4 has a positive effect on the optical frequency of the R-alcohol. At the same time, enantioselectivity in the reactions was almost absent upon reduction of 1,3-diphenylpropan-1-one with reagents obtained by partial neutralization of BH3. The best results of enantioselective reduction were shown by unsaturated alcohols: (1S,4S,5R) -6,8-dioxabicyclo[3.2.1]oct-2-en-4-ol and (1S,4S,5R)-4-methyl-6,8-dioxabicyclo[3.2.1]oct-2-en-4-ol, of which (1S,4S,5R)-6,8-dioxabicyclo[3.2.1]oct-2-en-4-ol was the most effective. It is likely that an increase in the enantioselectivity of reactions carried out in the presence of hydroxy derivatives of levoglucosenone is possible by obtaining more bulky chiral ligands, provided that the double bond is retained.

A simple synthesis of (±)-1,2,3,6-tetrahydro-2,3′-bipyridine (anatabine) and (±)-3-(2-piperidinyl)pyridine (anabasine) from lithium aluminum hydride and pyridine

1997 ◽  
Vol 75 (6) ◽  
pp. 616-620 ◽  
Author(s):  
Chi-Ming Yang ◽  
Dennis D. Tanner
Keyword(s):  
Catalytic Hydrogenation ◽  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Simple Synthesis ◽  
Lithium Aluminum ◽  
Pyridine Solution ◽  
Hydrolysis Of

The hydrolysis of a pyridine solution of lithium tetrakis(N-dihydropyridyl)aluminate (LDPA), which was prepared at 0 °C, yields a mixture of 1,4-, 1,2-, and 2,5-dihydropyridines (DHPs) in a ratio of 26:37:38. The subsequent reversible base-catalyzed condensation of a 1:1 mixture of 1,2- and 2,5-DHPs carried out in the presence of oxygen affords an 89% yield of (±)-anatabine. When the reaction mixture is allowed to stand in the presence of oxygen, anabasine is slowly formed from anatabine by the reaction of the residual DHPs. Anatabine can also be converted into (±)-anabasine by catalytic hydrogenation. Keywords: lithium aluminum hydride, pyridine, anatabine, anabasine.

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