Preparation of New Oxidized 18-α-Oleanane Derivatives

2005 ◽  
Vol 70 (9) ◽  
pp. 1447-1464 ◽  
Author(s):  
Miroslav Kvasnica ◽  
Iva Tišlerová ◽  
Jan Šarek ◽  
Jan Sejbal ◽  
Ivana Císařová
Keyword(s):  
Double Bond ◽  
Nmr Spectra ◽  
Biological Activities ◽  
Oxidative Cleavage ◽  
Allylic Oxidation ◽  
Unsaturated Ketone ◽  
Ruthenium Tetroxide ◽  
Unsaturated Compounds ◽  
Starting Compound ◽  
C Nmr

19β,28-Epoxy-4,5-seco-3,5-cyclo-18α-olean-3(5)-ene (2) is an appropriate compound for oxidations, which lead to new oxidized compounds with potential biological activities. Several oxidations were used such as epoxidation, allylic oxidation, oxidative cleavage of double bond and other ones. From the starting compound epoxides 3a, 3b and unsaturated ketone 4 were prepared. This ketone was further oxidized to diketone 6 and anhydride 7. The double bonds of all unsaturated compounds were cleaved with ruthenium tetroxide to afford new A-seco oleananes. The structure and stereochemistry of the compounds were derived from IR, MS, 1H and 13C NMR spectra (1D and 2D COSY, TOCSY, NOESY, HSQC, HMBC).

Preparation of C(18)-empiric 20,29,30-trinorlupane derivatives. 1H, 13C NMR and mass spectra

1986 ◽  
Vol 51 (3) ◽  
pp. 621-635 ◽  
Author(s):  
Václav Křeček ◽  
Jiří Protiva ◽  
Miloš Buděšínský ◽  
Eva Klinotová ◽  
Alois Vystrčil
Keyword(s):  
Nitrous Acid ◽  
Mass Spectra ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Allylic Oxidation ◽  
Hydroxyl Group ◽  
Methyl Groups ◽  
Unsaturated Ketone ◽  
H Nmr ◽  
C Nmr

Reaction of amide I with nitrous acid gave the olefins II, III and IV. On allylic oxidation of olefin IV α,β-unsaturated ketone V is formed from which olefins VIII and IX were prepared by a sequence of further reactions. Addition of hydrogen to the double bond of olefin IV and α,β-unsaturated ketone V takes place on catalytic hydrogenation from the β-side and leads to derivatives with cis-annellated rings D/E. This made the preparation of hydrocarbons VI and VII epimeric on C(18) possible, which represent reference compounds for the study of the effect of substituents on the chemical shifts of the methyl groups and the saturated carbon atoms of 18αH and 18βH-lupane derivatives. The configuration of the hydroxyl group in epimers XI and XII were derived from 1H NMR spectra. Deuteration of olefins III, IV and IX gave deuteriohydrocarbons XVI to XVIII. The 1H, 13C NMR and mass spectra of the substances prepared are discussed.

Preparation and Conformational Study of B-Ring Substituted Lupane Derivatives

2006 ◽  
Vol 71 (8) ◽  
pp. 1131-1160 ◽  
Author(s):  
Martin Dračínský ◽  
Simona Hybelbauerová ◽  
Jan Sejbal ◽  
Miloš Buděšínský
Keyword(s):  
Double Bond ◽  
Hydroxy Group ◽  
Molecular Modelling ◽  
Nmr Spectra ◽  
Hydroxy Derivative ◽  
Secondary Hydroxy Group ◽  
Conformational Study ◽  
Primary Hydroxy Group ◽  
Type 3 ◽  
C Nmr

New lupane-type triterpenoids with 5(6) double bond were prepared using the method of partial demethylation on carbon C-4. Hydroboration of the double bond led to 6α-hydroxy derivative. By the oxidation and following reduction of 6α-hydroxy derivative the 6-oxo and 6β-hydroxy derivatives were prepared. A new method for selective oxidation of secondary hydroxy group in the presence of primary hydroxy group was performed. The conformation of ring A of new lupane-type 3-oxo derivatives with a substituent on ring B was elucidated on the bases of 1H and 13C NMR spectra and molecular modelling.

Anhydrobetulin and its derivatives

1991 ◽  
Vol 56 (4) ◽  
pp. 886-904 ◽  
Author(s):  
Alois Vystrčil ◽  
Václav Křeček ◽  
Jiří Protiva ◽  
Miloš Buděšínský
Keyword(s):  
Double Bond ◽  
Alkaline Medium ◽  
Sodium Borohydride ◽  
Mass Spectra ◽  
Nmr Spectra ◽  
Cotton Effect ◽  
Addition Reactions ◽  
Chemical Transformations ◽  
C Nmr ◽  
Reduction Of Ketones

The structure of anhydrobetulin II and its derivatives I, III and IV has been solved using 1H and 13C NMR spectra, mass spectra and chemical transformations. It has been proven that in addition reactions the trisubstituted double bond is attacked selectively from the α-side under formation of D/E cis-annelated derivatives VIII, X and XI. The 22-oxo derivative XIII exhibits an anomalous Cotton effect and, in contrast to its saturated analogue XXVII,it is not epimerized in alkaline medium. Trinordiketone XXI easily epimerizes to a mixture in which the 17βH-epimer XXIb predominates, trinorketone XXIV is stable only if the annelation of rings D and E is trans. These differences are explained in terms of steric interactions of substituents in position 19. The steric course of reduction of ketones XIII and XXIV with sodium borohydride is described.

scholarly journals Selektive Metallierung von BicycIo[3.2.1]octa-2,6-dien, II Distannylierte Derivate und stannylierte tricyclische Sekundärprodukte / Selective Metalation of Bicyclo[3.2.1]octa-2,6-diene, II Distannylated Derivatives and Stannylated Tricyclic Secondary Products

1988 ◽  
Vol 43 (11) ◽  
pp. 1405-1415 ◽  
Author(s):  
N. Hertkorn ◽  
F. H. Köhler
Keyword(s):  
Nmr Spectroscopy ◽  
Low Temperature ◽  
Nmr Spectra ◽  
Considerable Change ◽  
Coupling Constants ◽  
Secondary Products ◽  
Starting Compound ◽  
Derivatives Of ◽  
C Nmr ◽  
Dibromo Derivative

Abstract Distannylated bicyclo[3.2.1]octa-2,6-diene (1) with (CH3)3 Sn groups in positions exo-4 and 7 (7a), endo-4 and 7 (7b), exo-4 and 6 (7c), and probably exo-4 and endo-4 (7d) are obtained when 1 is treated first with an excess of n-BuLi/t-BuOK in alkane and then with (CH3)3 SnCl. Byproducts are monostannylated derivatives of 1 and l,4-bis(trimethylstannyl)but-2-ene (3). The formation of 7a/b/c is best understood when the two possible bicyclo[3.2.1]octa-2,6-dienyl dianions are generated as intermediates. 3,exo-4-Bis(trimethylstannyl)bicyclo[3.2.1]octa-2,6-diene (7e) is ob-tained from the corresponding dibromo derivative of 1 and (CH3)3SnLi with 3-bromo-exo-4-trimethylstannylbicyclo[3.2.1]octa-2,6-diene (9) as an intermediate. The bicyclic stannyl com-pounds are susceptible to a 1,5-homopentadienyl shift of a (CH3)3Sn group at relatively low temperature when the starting compound has the stannyl group in position 4 of 1 and when positions 6 or 7 are unsubstituted. Tricyclo[3.2.1.02.7]oct-3-enes with (CH3)3Sn groups in positions exo-6 (5a), endo-6 (5b), 3 and exo-6 (10a), and 3 and endo-6 (10b) are thus obtained. On further heating, 10b gives l-trimethylstannyl-3-vinylbenzene (11). All compounds have been studied systematically by NMR spectroscopy including δ(119Sn), δ(13C), δ(1H), 4/5J(119/117Sn-119Sn), nJ(119/117Sn-13C) , nJ(119/117Sn-1H), 1J(13C-1H ) , and nJ(1H-1H ). Among all nuclei, 119Sn gives the most simple spectra. From the 13C NMR spectra a series of useful increments of (CH3)3Sn groups emerges. The most interesting coupling constants are 5J(119/117Sn-119Sn), for which a considerable change with the dihedral angle is established, and nJ(119/117Sn-13C). For n = 3 and 4 the latter are especially useful because their angular dependence leads to unambiguous signal assignments.

Synthesis and Photochemical Trasformations of 19-Phenylsulfonyl Provitamin D Analogue

1998 ◽  
Vol 63 (10) ◽  
pp. 1597-1612
Author(s):  
Piotr Grzegorzewski ◽  
Izabela Koladkiewicz ◽  
Jacek W. Morzycki ◽  
Rafal R. Sicinski
Keyword(s):  
Double Bond ◽  
Uv Irradiation ◽  
Efficient Method ◽  
Nmr Spectra ◽  
Complex Mixture ◽  
The Other ◽  
Allylic Oxidation ◽  
H Nmr ◽  
Nucleophilic Displacement ◽  
Displacement Reactions

The synthesis of provitamin D analogue 19-(phenylsulfonyl)androsta-5,7-diene-3β,17β-diyl 3-acetate 17-pivalate (20) has been accomplished from 19-hydroxyandrost-5-ene-3β,17β-diyl 3-acetate 17-pivalate. 19-(Phenylsulfonyl)androst-5-ene-3β,17β-diyl 3-acetate 17-pivalate (10), a precursor of 20, was first obtained in low yield in the nucleophilic displacement reactions of 19-halogenated-5-ene steroids with sodium benzenesulfinate. Then a more efficient method has been used, which involves protection of the double bond as an epoxide. Introduction of the C(7)-C(8) double bond into olefin 10 has been also achieved in two ways. The first involved bromination-dehydrobromination and the other consisted of an allylic oxidation of olefin 10 leading to enone and the Bamford-Stevens reaction of its tosylhydrazone. UV irradiation of 5,7-diene 20 resulted in formation of a complex mixture of products. The structures of five isolated compounds were established on the basis of their 1H NMR spectra and mechanistic rationale.

Functionalization of 3β,28-lupanediol diacetate with chromium(VI) oxide

1991 ◽  
Vol 56 (12) ◽  
pp. 2936-2949 ◽  
Author(s):  
Jan Sejbal ◽  
Jiří Klinot ◽  
Miloš Buděšínský ◽  
Jiří Protiva
Keyword(s):  
Double Bond ◽  
Functional Groups ◽  
Mass Spectra ◽  
Nmr Spectra ◽  
Functional Group ◽  
Oxygen Functional Group ◽  
Chromium Vi ◽  
C Nmr

The oxidation of 3β,28-lupanediol diacetate (I) with chromium(VI) oxide gives low yields of products with functional groups in the ring E as products of hydroxylation at the 19β position (IV, VI, and IX) and the 11-ketone VII which has been transformed into other lupane derivatives with an oxygen functional group at 11 position (VIII, XIII - XV) or with a 9(11)-double bond (XVI, XVII). Structure of the compounds prepared has been verified by their 1H and 13C NMR spectra as well as by their mass spectra.

13C NMR spectra of azachalcones

1981 ◽  
Vol 46 (6) ◽  
pp. 1486-1491 ◽  
Author(s):  
Tibor Liptaj ◽  
Vladimír Mlynárik ◽  
Milan Remko ◽  
Ján Ďurinda ◽  
Jozef Heger
Keyword(s):  
Double Bond ◽  
Carbonyl Group ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Stable Form ◽  
13C Nmr Spectra ◽  
Spectral Parameters ◽  
Olefinic Bond ◽  
Pcilo Method ◽  
C Nmr

13C NMR spectral parameters were obtained for chalcone and fourteen its aza- and diazaanalogues. Relative conformation of the carbonyl group with respect to the double bond was studied using changes in 3J(C(1')-Hα) and PCILO method. PCILO calculations together with experimental results show that with 2'-, 3'-, and 4'-azachalcones the s-cis isomer is the most stable form. Whereas the molecule of 2'-azachalcone is planar or nearly planar, in 3'- and 4'-azachalcones the carbonyl group and the olefinic bond planes make angle of 45°.

scholarly journals Physicochemical Characterization and Biological activities of Sulfated Polysaccharides from Cultivated Solieria filiformis Rhodophyta

2017 ◽  
Vol 12 (6) ◽  
pp. 1934578X1701200 ◽  
Author(s):  
Edgar Caamal-Fuentes ◽  
Daniel Robledo ◽  
Yolanda Freile-Pelegrín
Keyword(s):  
Nmr Spectra ◽  
Marine Alga ◽  
Biological Activities ◽  
Physicochemical Characterization ◽  
Sulfated Polysaccharides ◽  
Spectroscopic Techniques ◽  
Molecular Weights ◽  
Ft Ir ◽  
Solieria Filiformis ◽  
C Nmr

Crude and alkali treated carrageenan from the cultivated marine alga Solieria filiformis (Rhodophyta) were obtained, characterized and evaluated for their cytotoxic and antiprotozoal activities. Yields, molecular weights and chemical composition of carrageenans were determined. Their structures were elucidated through spectroscopic techniques including FT-IR and CP-MAS 13C NMR spectra. Crude and alkali treated carrageenan seems to be chemically similar to the iota-family carrageenan. Crude carrageenan showed antiprotozoal activity against Giardia intestinalis.

13C and 15N NMR spectra of 1-(3- or 4-substituted phenyl)-3-methyl-3-phenyltriazenes

1984 ◽  
Vol 49 (4) ◽  
pp. 963-969 ◽  
Author(s):  
Antonín Lyčka ◽  
Pavel Vetešník
Keyword(s):  
Double Bond ◽  
Nmr Spectra ◽  
15N Nmr ◽  
Free Rotation ◽  
Double Bond Character ◽  
Temperature Range ◽  
Nmr Signals ◽  
Bond Character ◽  
C Nmr

13C and 15N NMR spectra of ten 1-(3- or 4-substituted phenyl)-3-methyl-3-phenyltriazenes have been measured in deuteriochloroform. In the temperature range from 210 to 320 K the 13C NMR signals of both methyl and phenyl groups were not broadened, and no free rotation of the substituents at N(3)has been proved. From the values 2J(15N(2) 13C(5')) and 2J(15N(2)13C(1')) it was possible to determine conformation at the N(2) - N(3) bond which has partial double bond character. The value 1J(15N(1) 13C(1)) is equal to 1.0 Hz, which proves trans arrangement of the substituents at the N(1) = N(2) bond.

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