The Alkaloids of Crotalaria goreensis Guill. et Perr.: 7β-Hydroxy-1-methylene-8β- and 7β-Hydroxy-1-methylene-8α-pyrrolizidine

1961 ◽  
Vol 14 (2) ◽  
pp. 284 ◽  
Author(s):  
CCJ Culvenor ◽  
LW Smith
Keyword(s):  
Sulphuric Acid ◽  
Absolute Configuration ◽  
Main Product ◽  
The Other ◽  
Relative Configuration ◽  
Minor Alkaloid ◽  
Methylene Group

The principal alkaloid of Crotalaria goreensis Guill. et Perr. is 7β-hydroxy-1-methylene-8β-pyrrolizidine (II),* a (+)-heliotridane derivative with the relative configuration of heliotridine at C7 (absolute configuration 7R, 88). Of two minor alkaloids isolated, one is the 7β-hydroxy-8α diastereoisomer (V) (absolute configuration 7R, 8R). The other minor alkaloid is isomeric with (II) and (V) but does not possess a 1-methylene group. The alkaloid (V) and the enantiomer of the principal alkaloid have been synthesized by reduction of the appropriate 1-chloromethyl-7-hydroxy-1,2-dehydropyrrolizidine with zinc and sulphuric acid. In this reduction some of the 1-methyl-1,2-dehydropyrrolizidine is formed but the 1-methylenepyrrolizidine is the main product.

III.—On the Reduction of Ferric Iron (1) by Sulphurous Acid and (2) by Zinc Dust

1913 ◽  
Vol 32 ◽  
pp. 12-16
Author(s):  
Alexander Charles Cumming ◽  
E. W. Hamilton Smith
Keyword(s):  
Sulphuric Acid ◽  
Carbonate Rocks ◽  
Ferric Iron ◽  
Zinc Dust ◽  
The Other ◽  
Additional Contribution ◽  
Large Excess ◽  
Other Hand

So many papers have appeared on this subject that some apology seems desirable before making an additional contribution. The amount of published work on reduction with sulphurous acid is in itself an indication that many workers have found difficulties. It has been shown that the reduction does not take place in presence of large excess of hydrochloric or sulphuric acid, but the reduction will still occur while the reaction of the solution is strongly acid. On the other hand, Hillebrand (“Analysis of Silicate and Carbonate Rocks,” U.S. Bulletin, 442, p. 113) states if the solution after addition of sulphite is red in colour, it is too alkaline and acid must be added.

The Boger Synthesis of (-)-Vindoline

2013 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Absolute Configuration ◽  
Secondary Alcohol ◽  
Ring System ◽  
Simple Solution ◽  
Relative Configuration ◽  
Amine Oxidation ◽  
Formidable Challenge ◽  
Starting Point ◽  
La Jolla ◽  
Stereogenic Center

The periwinkle-derived alkaloids vinblastine 2a and vincristine 2b are still mainstays of cancer chemotherapy. The more complex half of these dimeric alkaloids, vindoline 1, presents a formidable challenge for total synthesis. Building on his previous work (Organic Lett. 2005, 7, 4539), Dale L. Boger of Scripps/La Jolla devised (J. Am. Chem. Soc. 2010, 132, 3685) a strikingly simple solution to this problem based on sequential cycloaddition. The starting point for the synthesis was the ester 3, derived from D-asparagine. This was extended to 4, condensation of which with 5 gave the enol ether 6. On heating, 7 cyclized to 8, which lost N2 to give the zwitterion 9. Addition of the intermediate 9 to the indole then gave 10. In one reaction, the entire ring system of vindoline, appropriately oxygenated, was assembled, with the original stereogenic center from D-asparagine directing the relative and absolute configuration of the final product. To complete the synthesis, the pendant carbon on 11 had to be incorporated into the pentacyclic skeleton. After adjusting the relative configuration of the secondary alcohol, the N was rendered nucleophilic by reduction of the amide to the amine. Oxidation delivered 14, which on activation as the tosylate smoothly rearranged to the ketone 15. Reduction and regioselective dehydration then completed the synthesis of vindoline 1.

scholarly journals Pyridine-Imidazlolium Salts: Oxidatively Cleavage of N-C Bond via Nitration

Molbank ◽  
10.3390/m1095 ◽  
2019 ◽  
Vol 2019 (4) ◽  
pp. M1095
Author(s):  
Dumitrela Cucu (Diaconu) ◽  
Violeta Mangalagiu
Keyword(s):  
Sulphuric Acid ◽  
Medicinal Chemistry ◽  
Oxidative Cleavage ◽  
Imidazolium Ring ◽  
Methylene Group

Azaheterocycles derivatives with pyridine-imidazole skeleton are compounds of great value for medicinal chemistry. We report herein the nitration of 1,1′-(pyridine-2,6-diylbis(methylene))bis{3-[2-(4-nitrophenyl)-2-oxoethyl]-1H-imidazol-3-ium} bromide using a typical mixture of nitric and sulphuric acid. The nitration occur with the oxidative cleavage of N–C bond between imidazolium ring and methylene group.

Enantioselective Arylation of 3-Carboxamide Oxindoles with Quinone Monoimines and Synthesis of Chiral Spirooxindole-benzofuranones

Synlett ◽  
2019 ◽  
Vol 30 (09) ◽  
pp. 1067-1072
Author(s):  
Hui Chen ◽  
Hui Liu ◽  
Si-Han Zhao ◽  
Shao-Bing Cheng ◽  
Xiao-Ying Xu ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Absolute Configuration ◽  
Tertiary Amine ◽  
The Other ◽  
X Ray ◽  
Quaternary Center ◽  
Crystal Structural ◽  
The Absolute

A highly enantioselective arylation of 3-carboxamide oxoindoles with quinone monoimines is described. Various 3-aryl-3-carboxamide oxindoles with an all-carbon quaternary center were obtained in moderate to good yields (up to 99%) with moderate to good enantioselectivities (up to 98%) in the presence of a bifunctional thiourea-tertiary amine catalyst. The absolute configuration of one product was determined by an X-ray crystal structural analysis and the absolute configurations of the other products can be assigned by analogy. Moreover, several chiral spirooxindole-benzofuranones were synthesized from the 3-aryl-3-carboxamide oxindoles in moderate yields with moderate to good enantioselectivities.

scholarly journals Colletinin A and 2,2″-Diepicolletinin A: Two New Bisflavan-3-ols from Rhododendron Collettianum

2008 ◽  
Vol 3 (5) ◽  
pp. 1934578X0800300
Author(s):  
Viqar Uddin Ahmad ◽  
Farman Ullah ◽  
Hidayat Hussain ◽  
Gilles Dujardin ◽  
Arnaud Martel ◽  
...  
Keyword(s):  
Absolute Configuration ◽  
2D Nmr ◽  
Nmr Analysis ◽  
Relative Configuration ◽  
The Absolute

Two new bisflavan-3-ols, named colletinin A (1) and 2,2″-diepicolletinin A (2) have been isolated from Rhododendron collettianum. Their structures were determined by means of 1D and 2D NMR analysis, aided by HREIMS data. The relative configuration was determined by means of 1H-1H NOESY correlation but the absolute configuration could not be established.

STUDIES IN THE POLYOXYPHENOL SERIES: IX. THE SYNTHESIS OF PAPAVERINE AND PAPAVERALDINE BY THE POMERANZ-FRITSCH METHOD

1955 ◽  
Vol 33 (5) ◽  
pp. 729-742 ◽  
Author(s):  
Donald A. Guthrie ◽  
Arlen W. Frank ◽  
C. B. Purves
Keyword(s):  
Sulphuric Acid ◽  
Acetyl Derivative ◽  
Mercury Complex ◽  
Crude Product ◽  
Group A ◽  
Methylene Group

Fritsch's cyclization of N-(α-veratrylveratrylidene)-aminoacetal in sulphuric acid was shown to give 1.1% of papaverine and 23% of an isomer, m.p. 164.5–165.5 °C.; hydrochloride, m.p. 212 °C. decomp., which was supposed to be 4,5-bis(3,4-dimethoxyphenyl)-2H-pyrrolenine, produced by an internal condensation of the acetal or the corresponding aldehyde with the reactive methylene group. A similar structure was proposed for another unidentified isomer prepared by Schlittler and Müller. Hydrogenation of Fritsch's acetal gave N-(α-veratryl-veratryl)-aminoacetal, m.p. 69.5–70 °C., which was cyclized to a base, m.p. 155.5–156 °C.; N-acetyl derivative, m.p. 203.5–204 °C., formulated as 2,3-bis(3,4-dimethoxyphenyl)-3-pyrroline. Substances presumed to be the intermediate aldehyde and aldol were isolated as colorless oils. Condensation of the diketone veratril with aminoacetal, followed by cyclization of the crude product, constituted a new two-step synthesis of papaveraldine in 8% yield, and the reduction of the latter to papaverine was known.Other crystalline compounds prepared incidentally and thought to be new were veratril monoanil, m.p. 172–173 °C.; α,α′-biveratrylideneaminoacetal, m.p. 101–102 °C.; a compound formulated as 2,3-bis(3,4-dimethoxyphenyl)-4-ethylmer-captopyrrolidine hydrochloride, m.p. 184–185 °C; from this an unidentified mercury complex, m.p. 109 °C. decomp.; 4,4′dibenzyloxy-3,3′-dimethoxy-desoxybenzoin, m.p. 141–142 °C; and its oxime, m.p. 137.5 °C.

LYCOCTONINE AND ITS OXIDATION PRODUCTS

1952 ◽  
Vol 30 (9) ◽  
pp. 627-645 ◽  
Author(s):  
O. E. Edwards ◽  
Léo Marion
Keyword(s):  
The Other ◽  
Oxidation Products ◽  
Hydroxyl Group ◽  
Ultraviolet Spectra ◽  
Primary Hydroxyl ◽  
Alkyl Groups ◽  
Methylene Group

The ultraviolet spectra, basic strengths, and N-alkyl groups of the aconite alkaloids are discussed. Pyropseudaconine has been shown to contain a conjugated system. The formulation C19H19–2,(OH)3,(OCH3)4NC2H5 has been confirmed for lycoctonine. Study of its oxidation products has shown that lycoctonine has a methylene group adjacent to the nitrogen and a primary hydroxyl group. The two remaining hydroxyls have been shown to be vicinal, with one probably secondary and the other tertiary. A carbinolamine structure is suggested for hydroxylycoctonine. The new bases, isolycoctonine, desoxylycoctonine, and des-(oxymethylene)-lycoctonine are described.

scholarly journals XVII. Note on the development of voltaic electricity by atmospheric oxidation of combustible gases and other substances

1890 ◽  
Vol 46 (280-285) ◽  
pp. 372-376 ◽  
Keyword(s):  
Porous Material ◽  
Sulphuric Acid ◽  
The Other ◽  
Atmospheric Oxidation ◽  
Platinum Black ◽  
Conducting Material ◽  
Conducting Film ◽  
Other Substances ◽  
Combustible Gases

About fourteen months ago we had the honour of communicating to the Society (‘Roy. Soc. Proc.,’ vol. 44, p. 182) the results of a large number of experiments made with electromotor cells, of which a special feature was that one of the plates of the combination consisted of an “aeration plate,” or layer of conducting material exposed to the atmosphere, and consequently superficially charged with a film of condensed air, which served as a means of indirectly effecting the oxidation of the other plate (when made of oxidisable metal), or of the fluid surrounding it (when the plate is of non-oxidisable material immersed in an oxidisable fluid). We showed that the E. M. F. of a given combination varies very considerably with the nature of the material of which the aeration plate is made, surfaces of platinum sponge, and especially platinum black, yielding the highest results when the electrolyte is dilute sulphuric acid; a convenient way of constructing the plates being to apply the spongy metal to the surface of unglazed earthenware, or other similar porous non-conducting material, so as to form a conducting film, the electrolytic fluid being absorbed in the porous material and so making contact.

Relative configuration, absolute configuration and absolute structure of three isomeric 8-benzyl-2-[(4-bromophenyl)(hydroxy)methyl]-8-azabicyclo[3.2.1]octan-3-ones

2013 ◽  
Vol 69 (3) ◽  
pp. 303-306 ◽  
Author(s):  
Krzysztof Brzezinski ◽  
Ryszard Lazny ◽  
Aneta Nodzewska ◽  
Katarzyna Sidorowicz
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Crystal Structures ◽  
Absolute Configuration ◽  
Compound I ◽  
Relative Configuration ◽  
Enantiomerically Pure ◽  
Space Groups ◽  
Intramolecular Hydrogen ◽  
Absolute Structure

The title compounds, C21H22BrNO2, are isomeric 8-benzyl-2-[(4-bromophenyl)(hydroxy)methyl]-8-azabicyclo[3.2.1]octan-3-ones. Compound (I), the (±)-exo,syn-(1RS,2SR,5SR,9SR) isomer, crystallizes in the hexagonal space groupR\overline{3}, while compounds (II) [the (+)-exo,anti-(1R,2S,5S,9R) isomer] and (III) [the (±)-exo,anti-(1RS,2SR,5SR,9RS) isomer] crystallize in the orthorhombic space groupsP212121andPna21, respectively. The absolute configuration was determined for enantiomerically pure (II). For the noncentrosymmetric crystal of (III), its absolute structure was established. In the crystal structures of (I) and (II), an intramolecular hydrogen bond is formed between the hydroxy group and the heterocyclic N atom. In the crystal structure of racemic (III), hydrogen-bonded chains of molecules are formedviaintermolecular O—H...O interactions. Additionally, face-to-edge π–π interactions are present in the crystal structures of (I) and (II). In all three structures, the piperidinone rings adopt chair conformations and theN-benzyl substituents occupy the equatorial positions.

XII. Some experiments on a solid compound of iodine and oxygene, and on its chemical agencies

1815 ◽  
Vol 105 ◽  
pp. 203-213 ◽  
Keyword(s):  
Sulphuric Acid ◽  
Royal Society ◽  
The Other ◽  
Alkaline Solutions ◽  
New Combinations ◽  
Solid Compound ◽  
Its Analysis ◽  
Binary Combination

In the two papers containing researches on iodine which the Royal Society has done me the honour of publishing in the Transactions, I have described a class of bodies consisting of iodine, oxygene, and different bases analogous to the hyper-oxymuriates. In the last of these papers, I mentioned, that I had not been able to procure any binary combination of iodine and oxygene from these compounds, neither by the method proposed by M. Gay Lussac, namely, the action of sulphuric acid on the oxyiode of barium, nor by other methods of my own institution; and that in experiments on the effects of the acids on the oxyiodes, new combinations only were formed. I have lately resumed this enquiry, and by pursuing a new and entirely different plan of operation, I have at last succeeded in combining oxygene and iodine. In the following pages I shall describe the circumstances which led me to ascertain the existence of this compound, and I shall detail some experiments on its analysis and its chemical agencies. In the course of my researches, I observed, that when a solution of the compound of iodine and chlorine was poured into alkaline solutions, or even into certain muriatic solutions, the precipitate was an oxyiode; and this fact seemed to indicate, that iodine had a stronger attraction for oxygene than chlorine; iodine, likewise, has an attraction for chlorine; it appeared, therefore, extremely probable, that euchlorine, or the gaseous combination of oxygene and chlorine, would be decomposed by heat, and two compounds formed, one of oxygene and iodine, and the other of iodine and chlorine, or that a triple compound would be produced from which chlorine could be easily separated, and on submitting the idea to the test of experiment, I found that I had not been deceived.

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