Synthesis of Linear Steroid Oligoesters Based on Etienic Acid

2002 ◽  
Vol 67 (11) ◽  
pp. 1709-1718 ◽  
Author(s):  
Miroslav Reschel ◽  
Miloš Buděšínský ◽  
Ivan Černý ◽  
Vladimír Pouzar ◽  
Pavel Drašar
Keyword(s):  
Carboxylic Acid ◽  
Nmr Spectra ◽  
Mixed Anhydride

Linear oligoesters based on etienic acid (3β-hydroxyandrost-5-ene-17β-carboxylic acid) containing 2-4 steroid units were prepared employing mixed anhydride esterification. NMR spectra of the oligomeric steroids have been fully assigned.

Anhydrous Chromium(III) Carboxylates: Reactions of CrO3 with Carboxylic Acid Anhydrides

1983 ◽  
Vol 38 (1) ◽  
pp. 42-44 ◽  
Author(s):  
Ramesh Kapoor ◽  
Ramneek Sharma
Keyword(s):  
Magnetic Susceptibility ◽  
Carboxylic Acid ◽  
Nmr Spectra ◽  
Octahedral Geometry ◽  
H Nmr ◽  
Chromium Vi ◽  
Carboxylate Groups ◽  
Different Types ◽  
Pure Chromium ◽  
Acid Anhydrides

Abstract Chromium(VI) oxide reacts with excess of carboxylic acid anhydrides [(RCO)2O where R = CH3, C2H5, n-C3H7 and CHCl2] to give pure chromium(III) carboxylates. Their IR and 1H NMR spectra suggest the presence of two different types of carboxylate groups. Magnetic susceptibility and absorption spectra favour an octahedral geometry around Cr.

Experimental and calculated 1H, 13C and 31P NMR spectra of pyridine-2-phosphono-4-carboxylic acid

2003 ◽  
Vol 648 (3) ◽  
pp. 215-224 ◽  
Author(s):  
Katarzyna Chruszcz ◽  
Małgorzata Barańska ◽  
Krzysztof Czarniecki ◽  
Bogdan Boduszek ◽  
Leonard M Proniewicz
Keyword(s):  
Carboxylic Acid ◽  
Nmr Spectra ◽  
31P Nmr ◽  
31P Nmr Spectra ◽  
13C And 31P Nmr

Thermal decomposition of ozonides. A complementary method to the Baeyer–Villiger oxidation of hindered ketones

1979 ◽  
Vol 57 (24) ◽  
pp. 3272-3277 ◽  
Author(s):  
Richard Lapalme ◽  
H.-Jürg Borschberg ◽  
Pierre Soucy ◽  
Pierre Deslongchamps
Keyword(s):  
Thermal Decomposition ◽  
Carboxylic Acid ◽  
Vinyl Acetate ◽  
Mixed Anhydride ◽  
Complementary Method ◽  
Villiger Oxidation

Treatment of vinyl acetate with ozone yields the mixed anhydride of acetic and formic acids and formaldehyde oxide. The formaldehyde oxide can be trapped by reaction with ketones yielding the corresponding ozonides. Thermal decomposition of these ozonides gave the corresponding lactone and (or) the corresponding olefin carboxylic acid. The ozonides were also prepared by the ozonolysis of the corresponding olefins.

The reaction of cystine and Alanine-3-sulphinic acid with halogens

1973 ◽  
Vol 26 (8) ◽  
pp. 1771 ◽  
Author(s):  
PG Gordon
Keyword(s):  
Amino Acids ◽  
Carboxylic Acid ◽  
Peptide Bond ◽  
Cysteic Acid ◽  
Mixed Anhydride ◽  
Mechanism Of Formation

Aqueous chlorine and bromine react with cystine, cysteine, alanine-3- sulphinic acid, and cystine S,S-dioxide to give cysteic acid (3) and cysteicylcysteic acid (2).' When the reaction is performed in the presence of other amino acids it is possible to obtain mixed peptides. The mechanism of formation of the peptide bond is discussed and a sulphonic-carboxylic acid mixed anhydride is proposed as an intermediate.

Dioxobis(Carboxylato)Chromium(VI) and Oxo(Carboxylato)Chromium(III): Reactions of CrO3 with Carboxylic Acid Anhydrides

1984 ◽  
Vol 39 (12) ◽  
pp. 1702-1705 ◽  
Author(s):  
Ramesh Kapoor ◽  
Ramneek Sharma ◽  
Pratibha Kapoor
Keyword(s):  
Carboxylic Acid ◽  
Ir Spectra ◽  
Low Temperatures ◽  
Nmr Spectra ◽  
Room Temperature ◽  
Equimolar Ratio ◽  
H Nmr ◽  
Chromium Vi ◽  
Polar Organic Solvents ◽  
Acid Anhydrides

Reactions of carboxylic acid anhydrides [(RCO)2O where R = CH3, C2H5, n-C3H7 and CHCl2] with excess of chromium (VI) oxide at low temperatures yield chromyl carboxylates, CrO2(OOCR)2. These compounds are non-conducting in polar organic solvents. IR spectra suggest the presence of both unidentate and bidentate carboxylato groups and discrete Cr = 0 units. The 1H NMR spectra show the presence of only one type of carboxylato group.Reactions of carboxylic acid anhydrides with CrO3 in equimolar ratio yield reduced chromium(III) com pounds o f the type CrO(OOCR) at room temperature. Their millimolar solutions in C6H5NO2, CH3NO2 and CH3CN are non-conducting. IR spectra, magnetic susceptibility and some other properties have been investigated. Both types of compounds are polymeric in nature having covalent structures.

scholarly journals Isolation and Structural Elucidation of Nitrogenous Secondary Metabolites from Terrestrial and Marine Streptomyces spp

2017 ◽  
Vol 12 (3) ◽  
pp. 1934578X1701200
Author(s):  
Mohamed Shaaban ◽  
Khaled A. Shaaban ◽  
Elisabeth Helmke ◽  
Iris Grün-Wollny ◽  
Hartmut Laatsch
Keyword(s):  
Carboxylic Acid ◽  
Nmr Spectra ◽  
Acid Methyl Ester ◽  
2D Nmr ◽  
Benzene Derivatives ◽  
Streptomyces Spp ◽  
Acid Methyl ◽  
2D Nmr Spectra ◽  
New Compounds ◽  
Related Compounds

Screening and chromatography of extracts from a terrestrial and a marine-derived streptomycete yielded two new nitrogenous benzene derivatives, namely ( S)- N-[3-hydroxy-1-(4-hydroxyphenyl)-propyl]-acetamide (1a), and ( R)-2-(1-methyl-2-oxopropylamino)-benzoic acid (2). Additionally, eight known compounds were isolated, 2-acetamidophenol, phenazine-1-carboxylic acid, phenazine-1-carboxylic acid methyl ester, perlolyrin, tyrosol, uracil, and anthranilic acid. The structures of the new compounds were deduced from high resolution mass, 1D and 2D NMR spectra and by comparison with related compounds from the literature. The absolute configuration of 1a and 2 was determined by comparison of experimental and calculated CD and ORD data.

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