ANNOTININE: THE REACTIONS OF THE CYCLIC ETHER FUNCTION

1954 ◽  
Vol 32 (3) ◽  
pp. 268-279 ◽  
Author(s):  
H. L. Meier ◽  
P. D. Meister ◽  
Léo Marion
Keyword(s):  
Chromic Acid ◽  
Cyclic Ether ◽  
The Other ◽  
Amino Group ◽  
Imino Group ◽  
Unsaturated Lactone ◽  
Clemmensen Reduction ◽  
Secondary Amino ◽  
Concentrated Solution ◽  
Chromous Chloride

Treatment of annotinine chlorohydrin with chromous chloride has been found to produce not only the already reported unsaturated lactone A (C16H21O2N), but also a second unsaturated lactone B (C16H21(23)O2N), and a hydroxylactone (C16H23O3N). Under the action of a concentrated solution of the same reagent the hydroxylactone is converted to the unsaturated lactone B. On hydrogenation the latter gives a dihydrolactone B which seems to contain a secondary amino group. Annotinine hydrate on treatment with thionyl chloride gives an unsaturated chlorolactone (C16H20O2NCl) which can be hydrogenated and subsequently dechlorinated to produce a third lactone C, different from either of dihydrolactones A or B, but which like the latter seems to contain an imino group. Oxidation of annotinine hydrate with chromic acid produces a hydroxyketone which can be converted into an oxime and, therefore, one of the hydroxyls of the hydrate is secondary while the other is probably tertiary. On the other hand, oxidation of annotinine with potassium permanganate gives rise to a lactam which by the Clemmensen reduction is converted to a mixture of lactam chlorohydrin and dihydrolactone A.

α-OBSCURINE AND β-OBSCURINE: STRUCTURE STUDIES

1953 ◽  
Vol 31 (10) ◽  
pp. 952-957 ◽  
Author(s):  
Barry P. Moore ◽  
Léo Marion
Keyword(s):  
Absorption Spectrum ◽  
Double Bond ◽  
Infrared Absorption ◽  
Infrared Absorption Spectrum ◽  
The Other ◽  
Ultraviolet Absorption Spectrum ◽  
Amino Group ◽  
Absorption Bands ◽  
Secondary Amino ◽  
Cyclic Lactam

The alkaloid hitherto described as obscurine has been shown to consist of a mixture of two bases, α-obscurine (C17H26ON2) and β-obscurine (C17H24ON2). Dehydregenation of α-obscurine by heating with palladium-charcoal gives rise to 7-methylquinoline and 6-methyl-α-pyridone. The infrared absorption spectrum of the base shows absorption bands indicative of a carbony and of a secondary amino group, possibly in a cyclic lactam, while absorption in the ultraviolet indicates the presence of a double bond conjugated with the carbonyl group. β-Obscurine on the other hand contains an α-pyridone ring as shown by its infrared absorption spectrum and also by the similarity of its ultraviolet absorption spectrum with that of 6-methyl-α-pyridone.

ANNOTININE: THE LACTONE RING

1954 ◽  
Vol 32 (3) ◽  
pp. 280-287 ◽  
Author(s):  
H. L. Meier ◽  
Léo Marion
Keyword(s):  
Lithium Aluminum Hydride ◽  
Chromic Acid ◽  
Aluminum Hydride ◽  
Cyclic Ether ◽  
Lithium Aluminum ◽  
Similar Reduction ◽  
Compound A ◽  
Compound C ◽  
Dihydroxy Compound ◽  
Chromous Chloride

The action of lithium aluminum hydride in dioxane solution on annotinine reduces the lactone and gives rise to a dihydroxy ether while the same reaction in tetrahydrofuran causes scission of the cyclic ether as well and produces a trihydroxy compound. The same trihydroxy compound is also obtainable by the similar reduction of annotinine chlorohydrin. Treatment of the trihydroxy compound with thionyl chloride converts it to a chlorine-containing sulphite ester which under the action of chromous chloride yields an unsaturated dihydroxy compound A, while under the conditions of the Clemmensen reaction, it yields an isomeric unsaturated dihydroxy compound B. Annotinine reacts with phenyl-lithium to give what seems to be a tetrahydroxy compound (C28H35O4N) which is oxidized by chromic acid to C28H33O4N. These reactions lead to two conclusions: (a) that hydrochloric acid and lithium aluminum hydride open the cyclic ether of annotinine in the same way, and (b) that the hydroxyl involved in the lactone is tertiary.

Two ubiquitin-like conjugation systems that mediate membrane formation during autophagy

2013 ◽  
Vol 55 ◽  
pp. 39-50 ◽  
Author(s):  
Hitoshi Nakatogawa
Keyword(s):  
Light Chain ◽  
Membrane Dynamics ◽  
The Other ◽  
Aminobutyric Acid ◽  
Amino Group ◽  
Autophagosome Formation ◽  
Acid Receptor ◽  
Receptor Associated Protein ◽  
Atg Proteins ◽  
C Terminus

In autophagy, the autophagosome, a transient organelle specialized for the sequestration and lysosomal or vacuolar transport of cellular constituents, is formed via unique membrane dynamics. This process requires concerted actions of a distinctive set of proteins named Atg (autophagy-related). Atg proteins include two ubiquitin-like proteins, Atg12 and Atg8 [LC3 (light-chain 3) and GABARAP (γ-aminobutyric acid receptor-associated protein) in mammals]. Sequential reactions by the E1 enzyme Atg7 and the E2 enzyme Atg10 conjugate Atg12 to the lysine residue in Atg5, and the resulting Atg12–Atg5 conjugate forms a complex with Atg16. On the other hand, Atg8 is first processed at the C-terminus by Atg4, which is related to ubiquitin-processing/deconjugating enzymes. Atg8 is then activated by Atg7 (shared with Atg12) and, via the E2 enzyme Atg3, finally conjugated to the amino group of the lipid PE (phosphatidylethanolamine). The Atg12–Atg5–Atg16 complex acts as an E3 enzyme for the conjugation reaction of Atg8; it enhances the E2 activity of Atg3 and specifies the site of Atg8–PE production to be autophagy-related membranes. Atg8–PE is suggested to be involved in autophagosome formation at multiple steps, including membrane expansion and closure. Moreover, Atg4 cleaves Atg8–PE to liberate Atg8 from membranes for reuse, and this reaction can also regulate autophagosome formation. Thus these two ubiquitin-like systems are intimately involved in driving the biogenesis of the autophagosomal membrane.

Special transport and neurological significance of two amino acids in a configuration conventionally designated as D.

1994 ◽  
Vol 196 (1) ◽  
pp. 297-305 ◽  
Author(s):  
H N Christensen ◽  
A A Greene ◽  
D K Kakuda ◽  
C L MacLeod
Keyword(s):  
Amino Acids ◽  
Receptor Site ◽  
Amino Group ◽  
Carboxylate Group ◽  
Gamma Aminobutyric Acid ◽  
Imino Group ◽  
Group A ◽  
The Central Nervous System ◽  
Lower Homolog ◽  
Alpha Amino Acid

We point out an ability of certain amino acids to be recognized at a biological receptor site as though their amino group bore, instead of an alpha relationship to a carboxylate group, a beta, gamma or delta relationship to the same or a second carboxylate group. For aspartate, the unbalanced position of its amino group between a pair of carboxylates allows its occasional biorecognition as a beta-rather than as an alpha-amino acid, whereas for proline and its homologs, their cyclic arrangement may allow the imino group, without its being replicated, to be sensed analogously as falling at either of two distances from the single carboxylate group. The greater separation might allow proline to be seen as biologically analogous to gamma-aminobutyric acid. This more remote positioning of the imino group would allow the D-form of both amino acids to present its amino group in the orientation characteristic of the natural L-form. The dual modes of recognition should accordingly be signalled by what appears to be low stereospecificity, actually due to a distinction in the enantiorecognition of the two isomers. Competing recognition for transport between their respective D- and L-forms, although it does not prove that phenomenon, has been shown for proline and, significantly, even more strongly for its lower homolog, 2-azetidine carboxylate. Such indications have so far revealed themselves rather inconspicuously for the central nervous system binding of proline, reviewed here as a possible feature of a role suspected for proline in neurotransmission.

Stereoselective C-O Ring Construction: The Oguri-Oikawa Synthesis of Lasalocid A

2011 ◽  
Author(s):  
Douglass Taber
Keyword(s):  
Cyclic Ether ◽  
Radical Addition ◽  
The Other ◽  
Asymmetric Dihydroxylation ◽  
University Of British Columbia ◽  
Complementary Approach ◽  
Aldehydes And Ketones ◽  
Group Attachment ◽  
Sharpless Asymmetric Epoxidation ◽  
The University

O-Centered radicals have been little used for C-O ring formation. Glenn M. Sammis of the University of British Columbia showed (Organic Lett. 2008, 10, 5083) that O-centered radicals could be generated efficiently, and that they cyclized with high diasterecontrol. Liming Zhang of the University of Nevada, Reno, continuing his studies of Au-activation of alkynes, uncovered (J. Am. Chem. Soc. 2008, 130, 12598) the bimolecular condensation of polarized alkynes such as 3 with aldehydes and ketones, including 4, to give the dihydrofuran with high diastereocontrol. Margarita Brovetto of the Universidad de la República, Montevideo, Uruguay, prepared (J. Org. Chem. 2008, 73, 5776) the precursor to the enantiomercially triol 6 by fermentation of bromobenzene with Pseudomonas putida 39/D. Cyclization of 6 gave 7 with high diastereocontrol. Petri M. Pihko of the University of Jyväskylä, Finland, found (Organic Lett . 2008, 10, 4179) that cyclization of 8, prepared by Sharpless asymmetric epoxidation followed by Sharpless asymmetric dihydroxylation, also proceeded with high diastereocontrol. Vincent Aucagne of the Université d’Orléans observed (Tetrahedron Lett. 2008, 49, 4750) that brief exposure of the sulfone 10 to t -BuOK at low temperature gave clean conversion to the kinetic diastereomer 11. At room temperature, similar conditions delivered the other, more stable diastereomer. Angeles Martín and Ernesto Suárez of the C. S. I. C., La Laguna, took advantage (Tetrahedron Lett. 2008, 49, 5179) of the facile generation of O-centered radicals in converting 12 to 14, having a stereocontrolled quaternary center. The transformation is thought to be proceeding by H-atom abstraction, then diastereocontrolled trapping of the C-radical so formed with the allyl stannane 13. Much of the effort toward alkylated cyclic ether construction has been focused on alkyl group attachment adjacent to the ring oxygen. Torsten Linker of the University of Potsdam developed (J. Am. Chem. Soc. 2008, 130, 16003) a complementary approach, stereocontrolled oxidative radical addition of malonate 16 to glycals such as 15 to give the 3-alkyl substituted 17.

XII.—Note on the Sublimation of Sugars

1917 ◽  
Vol 36 (3-4) ◽  
pp. 216-218
Author(s):  
Sudhamoy Ghosh
Keyword(s):  
The Other ◽  
Concentrated Solution ◽  
Alcohol Vapour

The literature of the sugars would appear to show that no sugars have hitherto been observed to sublime with the exception of glycolose, CH2OH CHO, which is described as being “perceptibly volatile with water and alcohol vapour under diminished pressure, especially from a pure, concentrated solution” (Lippmann, Chemie der Zuckerarten, p. 4). This substance, being the first of the sugar series, might be expected to have properties somewhat different from the other members of the series, which are usually looked upon as non-volatile. Experiments with rhamnose and fructose appear to show that under diminished pressure they do sublime.

Amino Acid Salt Catalyzed Asymmetric Addition Reaction of Acetylacetone to Maleimides and 2-(2-Oxoindolin-3-ylidene)malononitriles

Synlett ◽  
2019 ◽  
Vol 30 (10) ◽  
pp. 1241-1245 ◽  
Author(s):  
Haiyan Wu ◽  
Hongxin Liu ◽  
Juan Li ◽  
Xinhua Li ◽  
Hong-Ping Xiao ◽  
...  
Keyword(s):  
Amino Acid ◽  
Addition Reaction ◽  
Optical Purity ◽  
Activation Mechanism ◽  
Amino Group ◽  
Acid Salt ◽  
Natural Amino Acid ◽  
Catalytic Potential ◽  
Amino Acid Salt ◽  
Secondary Amino

The exploration of catalytic potential of natural amino acid salt in activation of 1,3-dicarbonyls was carried out, in which maleimides and 2-(2-oxoindolin-3-ylidene)malononitriles were found to be good electrophiles and afforded the desired products with excellent yield and moderate optical purity. Control experiments showed that the secondary amino group of barium (S)-prolinate is critical to the catalytic activity as well as enantiocontrol, thus revealed an enamine activation mechanism is possible in the present methodology.

THE METABOLISM OF PUTRESCINE (1,4-DIAMINOBUTANE) BY MYCOBACTERIA ISOLATED FROM FISH: II. STUDIES WITH ARSENITE-INHIBITED CELLS AND CELL-FREE EXTRACTS

1967 ◽  
Vol 13 (5) ◽  
pp. 521-531 ◽  
Author(s):  
T. P. T. Evelyn
Keyword(s):  
Succinic Acid ◽  
Tricarboxylic Acid Cycle ◽  
Significant Proportion ◽  
Tricarboxylic Acid ◽  
The Other ◽  
Aminobutyric Acid ◽  
Succinic Semialdehyde ◽  
Amino Group ◽  
Intact Cells ◽  
Acid Cycle

Three mycobacterial strains isolated from fish degraded putrescine by a pathway in which γ-aminobutyraldehyde (Δ′-pyrroline), γ-aminobutyric acid, succinic semialdehyde, and succinic acid were intermediates. These results agree substantially with those of other workers using different microorganisms. Intact cells utilized γ-aminobutyric acid in a transaminase reaction with endogenously supplied α-ketoglutarate to produce succinic semialdehyde and glutamate. Studies with arsenite-poisoned cells showed that a significant proportion of putrescine was metabolized via pyruvate and alanine. When putrescine-1,4-14C was substrate, HCl extracts of cells contained radioactive aspartate and glutamate in addition to alanine. The further metabolism of succinate therefore proceeded in two directions: one yielding oxalacetate and α-ketoglutarate by way of the tricarboxylic acid cycle, and the other branching off the cycle to yield pyruvate. Studies with cell-free extracts suggested that putrescine nitrogen was assimilated via glutamate, which served as the amino-group donor to yield alanine and aspartate.

Rapidreaction between unifunctional molecules and molecules unifunctional at one position and n-functional at another

1957 ◽  
Vol 10 (2) ◽  
pp. 99 ◽  
Author(s):  
HG Higgins
Keyword(s):  
The Other ◽  
Rate Equations ◽  
Amino Group

Rate equations for the reaction between A and B, where B is unifunctional, and A is unifunctional at one and n-functional at the other of two independent positions, lead to expressions for the final relative concentrations of the reactants and products in terms of the initial concentrations of A and B, the ratio of the velocity constants at the two positions on A, and the functionality n. These results are applied to the reaction of tryptophane with p-diazobenzenesulphonic acid, in which it appears that the indole group reacts somewhat faster than the amino group.

scholarly journals The antiseptic and trypanocidal action of certain styryl and anil quinoline carboxylamides.*

1932 ◽  
Vol 110 (767) ◽  
pp. 249-260
Keyword(s):  
Amide Group ◽  
The Other ◽  
Amino Group ◽  
Active Compounds ◽  
Basic Group ◽  
Urethane Group ◽  
Highly Active ◽  
Quaternary Compounds ◽  
Quinoline Series

In the case of quaternary compounds of the styryl quinoline series and of the analogous benzthiazole derivatives a powerful trypanocidal effect in vivo has been shown to depend on the presence in the substance of a free basic group in one of the nuclei, and anacylamino (especially acetyl) or urethane group in the other, and also on the styryl linkage—each playing a definite part in contributing to the action (Browning, Cohen, Ellingworth and Gulbransen, 1929, 1931). This is exemplified by 2( p -aminostyryl)-6 acetylamino quinoline methochloride (No. 8), 2( p -dimethylamino styryl)-6 acetylamino quinoline methochloride (No. 25), 2( p -acetylamino)-6 dimethylamino quinoline methochloride (No. 90) and 2( p -dimethylamino styryl) quinolyl (6) urethane (Me) methochloride (No. 125). The effect of acetylation of the amino group parallels that dis­covered by Ehrlich and his co-workers in the case of p -amino phenyl arsinic acid. Gough and King (1930) have recently made the important observation that in the latter series the introduction of an amide group converts the therapeutically inactive carboxylic and sulphonic acids into active compounds. Accordingly, the effect of substituting a carboxylamide group for the acylamino in compounds of the type of No. 25 and its anil analogue (No. 62) has been investigated. In addition, the position of the carboxylamide group has been varied. These substances were further examined for antiseptic action, the results being shown in the table. Trypanocidal properties have been tested on T. brucei infections in mice as in previous work. The striking observation has been made that only those compounds with the carboxylamide group in the 6 position are therapeutically active, the anils being only slightly less effective than the styryl analogues ( cf . Nos. 410, 409 and 385, 403). This contrasts with what is found in the acetylamino derivatives, since the styryl compounds of the latter are highly active as compared with the corresponding anils. The carboxy-ethylamides (420, 419) are more toxic and less trypanocidal than the corresponding amides and methylamides.

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