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.

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.

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 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.

Formen des Diphenylgermaniumoxids(Ph2GeO)x, x = 3, 4, n / Phases of Diphenylgermanium Oxide(Ph2GeO)x, x = 3, 4, n

1984 ◽  
Vol 39 (7) ◽  
pp. 868-875 ◽  
Author(s):  
Ludwig Roß ◽  
Martin Dräger
Keyword(s):  
Crystal Structure ◽  
Thermal Analysis ◽  
Vibrational Spectra ◽  
Mass Spectra ◽  
Nmr Spectra ◽  
Membered Ring ◽  
Tetragonal Crystals ◽  
Hydroxy Groups ◽  
C Nmr

Diphenylgermanium oxide can be obtained trimeric (6 -membered ring, monoclinic crystals), tetrameric (8 -membered ring, monoclinic and tetragonal crystals and monoclinic with half a mole of crystal ethanol) and polymeric with terminating hydroxy groups. Transitions are investigated by thermal analysis, mass spectra and 13C NMR spectra. The vibrational spectra (I. R . and Raman) of the forms are discussed . The crystal structure of the monoclinic (Ph :GeO)4 has been determined and refined to R = 0.051. The symmetry of the molecule is near to S4 (distances Ge - O 174.7 - 176.2, Ge - C 190.0 - 194.6 pm, angles Ge - O - Ge 131.2 - 136.9, O - Ge - O 107.8 -110.3 °).

scholarly journals Highly reactive, liquid diacrylamides via synergistic combination of spatially arranged curing moieties

2017 ◽  
Vol 13 ◽  
pp. 372-383 ◽  
Author(s):  
Maximilian Maier ◽  
Magnus S Schmidt ◽  
Markus Ringwald ◽  
Christoph P Fik
Keyword(s):  
Refractive Index ◽  
Mechanical Testing ◽  
Functional Groups ◽  
Nmr Spectra ◽  
Dsc Measurements ◽  
Alkyl Groups ◽  
Before And After ◽  
Reactive Liquid ◽  
Synergistic Combination ◽  
C Nmr

Six polymerizable N,N’-diacylamides containing spatially arranged N-acryl, N-allyl and/or N-alkyl groups were prepared via two-step syntheses and characterized by 1H/13C NMR-spectra, refractive index (RI) and viscosity measurements. Photo DSC measurements on activated samples provided reactivity parameters ∆H p, R p,max and t max, while FTIR spectra before and after curing elucidated the underlying polymerization mechanism. Mechanical testing of the obtained polymers exhibited gradual differences in network densities, depending on the intramolecular arrangement and number of functional groups. Overall, a general building principle for highly reactive, liquid diacrylamides via synergistic combination of optimally arranged functional groups could be identified. The highest possible level of intramolecular synergism was found for low viscous N,N'-diacryloyl-N,N'-diallyl-1,4-but-2-enediamine.

The structure of demethoxyrapamycin

1982 ◽  
Vol 60 (15) ◽  
pp. 2046-2047 ◽  
Author(s):  
John A. Findlay ◽  
Jia-Sen Liu ◽  
D. Jean Burnell ◽  
Thomas T. Nakashima
Keyword(s):  
High Field ◽  
Mass Spectra ◽  
Nmr Spectra ◽  
Antifungal Antibiotic ◽  
C Nmr

The structure 2, 29-demethoxyrapamycin, is proposed for a new antibiotic from Streptomyceshygroscopicus and has been deduced by comparison of high field 1H and 13C nmr spectra, ir, uv, and mass spectra, and ORD/CD curves with those of the known antifungal antibiotic rapamycin 1.

scholarly journals Functional group composition of ambient and source organic aerosols determined by tandem mass spectrometry

2010 ◽  
Vol 10 (15) ◽  
pp. 7041-7055 ◽  
Author(s):  
J. Dron ◽  
I. El Haddad ◽  
B. Temime-Roussel ◽  
J.-L. Jaffrezo ◽  
H. Wortham ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Functional Groups ◽  
Mass Spectra ◽  
Functional Group ◽  
Group Composition ◽  
Organic Aerosol ◽  
Tandem Mass ◽  
Wood Combustion ◽  
Alpine Valley ◽  
Aerosol Sources

Abstract. The functional group composition of various organic aerosols (OA) is investigated using a recently developed analytical approach based on atmospheric pressure chemical ionisation-tandem mass spectrometry (APCI-MS/MS). The determinations of three functional groups contents are performed quantitatively by neutral loss (carboxylic and carbonyl groups, R-COOH and R-CO-R´ respectively) and precursor ion (nitro groups, R-NO2) scanning modes of a tandem mass spectrometer. Major organic aerosol sources are studied: vehicular emission and wood combustion for primary aerosol sources; and a secondary organic aerosol (SOA) produced through photooxidation of o-xylene. The results reveal significant differences in the functional group contents of these source aerosols. The laboratory generated SOA is dominated by carbonyls while carboxylics are preponderate in the wood combustion particles. On the other hand, vehicular emissions are characterised by a strong nitro content. The total amount of the three functional groups accounts for 1.7% (vehicular) to 13.5% (o-xylene photooxidation) of the organic carbon. Diagnostic functional group ratios are then used to tentatively discriminate sources of particles collected in an urban background environment located in an Alpine valley (Chamonix, France) during a strong winter pollution event. The three functional groups under study account for a total functionalisation rate of 2.2 to 3.8% of the organic carbon in this ambient aerosol, which is also dominated by carboxylic moieties. In this particular case study of a deep alpine valley during winter, we show that the nitro- and carbonyl-to-carboxylic diagnostic ratios can be a useful tool to discriminate sources. In these conditions, the total OA concentrations are highly dominated by wood combustion OA. This result is confirmed by an organic markers source apportionment approach which assess a wood burning organic carbon contribution of about 60%. Finally, examples of functional group mass spectra of all aerosols under study are presented, and additional perspectives offered by the mass spectra in terms of OA characterisation are discussed.

Functionalization of Lupane with Chromium(VI) Oxide. A Remark on the Structure of Clerodone

1996 ◽  
Vol 61 (9) ◽  
pp. 1371-1379 ◽  
Author(s):  
Jan Sejbal ◽  
Jiří Klinot ◽  
Miloš Buděšínský
Keyword(s):  
Chromium Oxide ◽  
Mass Spectra ◽  
Methoxy Group ◽  
H Nmr ◽  
Chromium Vi ◽  
Hydride Reduction ◽  
C Nmr

The reaction of lupane (1) with chromium oxide gave lup-2-en-1-one (3), lupan-12-one (2), lupan-16-one (isolated after hydride reduction as lupan-16α-ol (4)), and lup-18-en-21-one (5) in low yields. The same oxidation of 3β,28-dimethoxylupane (11) afforded no products of functionalization in non-activated positions; only products of oxidation of the 3β-methoxy group and of the oxidation cleavage of the A ring were obtained, viz. 28-methoxylupan-3β-ol formate (12), 28-methoxylupan-3-one (14), and 28-methoxy-2-norlupane-1,3-dioic anhydride (13). The structure of the compounds obtained was confirmed by their 1H NMR, 13C NMR, and mass spectra. The lupan-12-one (2) prepared is not identical with clerodone, whose isolation from Clerodendron infortunatum BHAT. was described in 1965 and to which the structure of lupan-12-one was then ascribed.

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.

scholarly journals Synthesis, Characterization and Antibacterial Activity of Schiff Bases and their Metal Complexes Derived from 4-Acyl-1-phenyl-3-methyl-2-pyrazolin-5-ones and 2-Amino-4(4'-methylphenyl)-thiazole

2010 ◽  
Vol 7 (4) ◽  
pp. 1396-1406 ◽  
Author(s):  
A. S. Thakar ◽  
K. K. Singh ◽  
K. T. Joshi ◽  
A. M. Pancholi ◽  
K. S. Pandya
Keyword(s):  
Antibacterial Activity ◽  
Schiff Bases ◽  
Elemental Analysis ◽  
Mass Spectra ◽  
Nmr Spectra ◽  
Electrical Conductance ◽  
H Nmr ◽  
Infrared Spectral ◽  
Ft Ir ◽  
C Nmr

4-Acyl-1-phenyl-3-methyl-2-pyrazolin-5-ones condensed with 2-amino-4(4'-methylphenyl)-thiazole to form Schiff base. These Schiff bases from complexes of type ML22H2O (M=Mn, Fe, Co, Ni and Cu). Elemental analysis, magnetic susceptibility, electrical conductance, electronic and Infrared spectral data suggested octahedral structure for the complexes. All the compounds were tested for their antibacterial activity. The result indicates that the growth of the tested organism was inhibited by most of the compounds. These Schiff bases are characterized by elemental analysis, mass spectra,1H-NMR spectra,13C NMR spectra and FT IR spectra.

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