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.

13C-NMR-Spektroskopie an polycyclischen Aromaten, IIΙ Die 13C-NMR-Spektren von Amino- und Dimethylaminonaphthalinen /13C NMR Spectroscopy of Polycyclic Aromatics, III The 13C NMR Spectra of Amino- and Dimethylaminonaphthalenes

1975 ◽  
Vol 30 (9-10) ◽  
pp. 794-799 ◽  
Author(s):  
Ludger Ernst
Keyword(s):  
13C Nmr ◽  
High Field ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Double Resonance ◽  
Substituent Effects ◽  
13C Nmr Spectroscopy ◽  
Polycyclic Aromatics ◽  
Electrophilic Reagents ◽  
C Nmr

The 13C NMR spectra of twelve amino-, dimethylamino-, diamino-, and bis(dimethylamino)naphthalenes are completely assigned by selective 13C{1H} double resonance and by interpretation of proton-coupled spectra. Strong substituent effects (Δδ) upon chemical shifts are observed and can largely be accounted for by mesomerism. The pronounced high-field shifts of C-6 in the 2-amino- and 2-dimethylaminonaphthalenes coincide with the enhanced reactivity of this position towards electrophilic reagents. In 1-dimethylaminonaphthalene and even more so in 1-dimethylamino-2-methylnaphthalene, conjugation is inhibited for steric reasons and Δδ’s are greatly diminished, thus giving an estimate for the contribution of resonance to substituent-induced shifts in the unhindered compounds. In two 1,8-disubstituted naphthalenes there are large deviations from additivity of substituent effects.

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 °).

On the chemistry and high field nuclear magnetic resonance spectroscopy of rapamycin

1980 ◽  
Vol 58 (6) ◽  
pp. 579-590 ◽  
Author(s):  
John A. Findlay ◽  
Lajos Radics
Keyword(s):  
High Field ◽  
Nmr Spectra ◽  
Resonance Spectroscopy ◽  
X Ray ◽  
Conformational Isomers ◽  
H Nmr ◽  
Neutral Compounds ◽  
Complete Assignment ◽  
Hydrolysis Of ◽  
C Nmr

Base catalysed hydrolysis of rapamycin (C51H79NO13) affords six neutral compounds identified by chemical and spectroscopic means as 2a, 3b, 3d, 5, 2,4-dimethylphenol, and L(−)-piperidine-2-carboxylic acid 6, and whose generation has been plausibly rationalized. These findings as well as detailed analyses of 13C nmr and 1H nmr spectra provide independent corroboration of the X-ray derived rapamycin crystal structure 1. Structurally homogeneous in the solid state, rapamycin is found to occur in solutions as a mixture of two conformational isomers (approximately 4:1). Through nearly complete assignment of the high field 1H (400 MHz) and 13C (100.6 MHz) nmr spectra, the isomerism is shown to be associated with trans–cis rotation of an amidic bond within the 31-membered macrolide ring. The predominant form corresponds to the conformer portrayed by X-ray analysis.

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 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.

Photochemische Reaktionen von Übergangsmetall-Olefin-Komplexen, II Die Umsetzung von Tricarbonyl-η-1.3.5-cycloheptatrien-chrom(O) mit substituierten Fulvenen /Photochemical Reactions of Transition Metal Olefin Complexes, II The Reaction of Tricarbonyl-η-1,3,5-cycloheptatriene-chromium(O) with Substituted Fulvenes

1978 ◽  
Vol 33 (11) ◽  
pp. 1285-1290 ◽  
Author(s):  
Cornelius G. Kreiter ◽  
Hans Kurz
Keyword(s):  
Transition Metal ◽  
Mass Spectra ◽  
Nmr Spectra ◽  
Uv Light ◽  
Photochemical Reactions ◽  
The Other ◽  
Chelate Ligand ◽  
Chromium Complex ◽  
High Yields ◽  
C Nmr

Abstract When tricarbonyl-η-1,3,5-cycloheptatriene-chromium(O) (1) and 6,6-dimethylfulvene or tricarbonyl-η-6,6-dimethylfulvene-chromium(O) and 1,3,5-cyeloheptatriene are irradiated with UV light, a red crystalline dicarbonyl-chromium complex with an η3 -1′,2′,3′-(2-cyclohepta-2′, 4′ -dien 1′ ,6′-ylene)-η5 (2-cyclopentadienylidene)propane chelate ligand, Cr(CO)2C15H18 (2), is formed in high yields. Under the same conditions, 1 with 6,6-diphenylfulvene yields two isomeric complexes. One of them, Cr(CO)3C25H22 (3), is analoguous to 2 and contains the η3 -1′,2′,3′-cyclohepta-2′,4′-dien-1′ ,6′ / -ylene-η5 -cyclopentadienylidene-diphenyl-methane chelate ligand. The other one is the dicarbonyl η3 -1′,2′,3′-cyclohep-tatrienyl- η5 diphenylmethylcyclopentadienyl-chromium(O), Cr(CO)2(C7H7)(Ci8H15) (4). The complexes were characterized by analysis and mass spectra. The structures are based on IR, and 1H and 13C NMR spectra. Einführung

New synthesis of 2-amino-4-oxopyrido[3,2-e]-1,3-thiazines and 1-alkyl(aryl)pyrido[3,2-e]-2-thiouracils

1983 ◽  
Vol 48 (11) ◽  
pp. 3315-3328 ◽  
Author(s):  
Dušan Koščík ◽  
Pavol Kristian ◽  
Jozef Gonda ◽  
Emília Dandárová
Keyword(s):  
Mass Spectra ◽  
Nmr Spectra ◽  
Secondary Amines ◽  
Primary Amines ◽  
Addition Reactions ◽  
Alkyl Aryl ◽  
H Nmr ◽  
New Synthesis ◽  
Subsequent Cyclization ◽  
C Nmr

Addition reactions of 2-chloronicotinoyl isothiocyanate with primary and secondary amines and subsequent cyclization of intermediate thioureas represent new synthesis of pyrido[3,2-e]thiouracil and pyrido[3,2-e]-thiazine derivatives. 2-Amino-4-oxopyrido[3,2-e]-1,3-thiazines are formed upon heating the reaction components in ethanol, whereas 1-alkyl(aryl)pyrido[3,2-e]-2-thiouracils are products of alkali-catalyzed reaction. In reaction with primary amines the corresponding thioureas were isolated as intermediates, whereas secondary amines reacted directly to give the pyridothiazine derivatives. Structure of the synthesized compounds was confirmed by their 13C NMR and mass spectra; also the IR and 1H NMR spectra are in accord with the suggested formulae.

scholarly journals Crystal structures of {1,1,1-tris[(salicylaldimino)methyl]ethane}gallium as both a pyridine solvate and an acetonitrile 0.75-solvate and {1,1,1-tris[(salicylaldimino)methyl]ethane}indium dichloromethane solvate

2020 ◽  
Vol 76 (5) ◽  
pp. 615-620
Author(s):  
Dominic L. Ventura ◽  
William W. Brennessel ◽  
William S. Durfee
Keyword(s):  
Mass Spectra ◽  
Nmr Spectra ◽  
Intermolecular Hydrogen Bonding ◽  
Melting Points ◽  
Deprotonated Form ◽  
Main Group Elements ◽  
Hydrogen Bonding Interactions ◽  
Infra Red ◽  
Resolution Mass ◽  
C Nmr

The sexadentate ligand 1,1,1-tris[(salicylideneamino)methyl]ethane has been reported numerous times in its triply deprotonated form coordinated to transition metals and lanthanides, yet it has been rarely employed with main-group elements, including in substituted forms. Its structures with gallium and indium are reported as solvates, namely, ({[(2,2-bis{[(2-oxidobenzylidene)amino-κ2 N,O]methyl}propyl)imino]methyl}phenololato-κ2 N,O)gallium(III) pyridine monosolvate, [Ga(C26H24N3O3)]·C5H5N, the acetonitrile 0.75-solvate, [Ga(C26H24N3O3)]·0.75C2H3N, and ({[(2,2-bis{[(2-oxidobenzylidene)amino-κ2 N,O]methyl}propyl)imino]methyl}phenololato-κ2 N,O)indium(III) dichloromethane monosolvate, [In(C26H24N3O3)]·CH2Cl2. All three metal complexes are pseudo-octahedral and each structure contains multiple weak C—H...O and/or C—H...N intermolecular hydrogen-bonding interactions. The syntheses and additional characterization in the forms of melting points, high-resolution mass spectra, infra-red (IR) spectra, and 1H and 13C NMR spectra are also reported.

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.

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