Derivatives of 5α-androstan-3α- and 3β-ol with acrylate side chain

1990 ◽  
Vol 55 (5) ◽  
pp. 1243-1256 ◽  
Author(s):  
Vladimír Pouzar ◽  
Hana Chodounská ◽  
Dalibor Sameš ◽  
Pavel Drašar ◽  
Miroslav Havel
Keyword(s):  
Ethyl Esters ◽  
Side Chain ◽  
Protecting Group ◽  
Derivatives Of

Hydroxy derivatives I, II, III, XVII and XX were oxidized to give the respective aldehydes IV, V, VI, XVIII and XXI which were further converted by Wittig-Horner reaction into unsaturated methyl and ethyl esters. Removal of the acetal protecting group in position 3 afforded methylesters X, XXIV and XXXVI and ethyl esters XIV, XXV and XXXVII. Compounds XXIV, XXV, XXXVI and XXXVII were converted into the corresponding hemisuccinates XXVIII, XXIX, XL and XLI and β-D-glucosides XXXII, XXXIII, XLIV and XLV.

Effect of N-methylation and chain length on kinetic constants of trypsin substrates. ε-N-Methyllysine and homolysine derivatives as substrates

1970 ◽  
Vol 48 (10) ◽  
pp. 1122-1131 ◽  
Author(s):  
John H. Seely ◽  
N. Leo Benoiton
Keyword(s):  
Chain Length ◽  
Methyl Esters ◽  
Kinetic Constants ◽  
Ethyl Esters ◽  
Side Chain ◽  
Amino Acid Derivatives ◽  
Specific Substrate ◽  
Small Peptides ◽  
Side Chain Length ◽  
Derivatives Of

The action of trypsin on the following amino acid derivatives has been investigated: the ethyl esters of ε-N-mono-, ε-N-di-, and ε-N-tri-methyl-L-lysine; the ethyl esters of the homologues of lysine and arginine; the methyl ester and amide of the α-N-benzoyl-DL-homolysine; the methyl esters and amides of the α-N-benzoyl derivatives of ε-N-di- and ε-N-tri-methyllysine; and poly ε-N-methyllysine. Derivatives of L-ornithine, DL-2,8-diaminooctanoic acid, ε-N-dimethyl-, ε-N-trimethyl-, and ε-N-formyl-L-lysine were not substrates of trypsin. ε-N-Dimethyl-L-lysine derivatives did not inhibit the action of trypsin on a specific substrate. DL-Homolysine derivatives were hydrolyzed with kcat's one to two orders of magnitude lower than those of lysine derivatives, but their Km's were only 1.5–3 times higher. ε-N-Methyl-L-lysine derivatives were hydrolyzed at rates similar to those for DL-homolysine derivatives, and had Km's 25–115 times those of lysine derivatives. Plots of Km and kcat/Km versus side-chain length of the substrate for the ethyl esters of all the homologues of lysine and arginine indicated a correlation between these kinetic constants and side-chain length, and that the best substrate would have a side-chain length between those of lysine and arginine. Poly-ε-N-methyl-L-lysine was degraded to small peptides by trypsin.

Absolute configuration at C(20) of the derivatives of 21-nor-5α-cholane-20,24-diol

1980 ◽  
Vol 45 (9) ◽  
pp. 2443-2451
Author(s):  
Vladimír Pouzar ◽  
Miroslav Havel
Keyword(s):  
Absolute Configuration ◽  
Side Chain ◽  
Chemical Correlation ◽  
The Absolute ◽  
Derivatives Of

Derivatives of 21-nor-5α-cholane-20,24-diol XI and XIX were prepared by stepwise construction of the side-chain in the position 17β. Their absolute configuration at C(20) was determined on the basis of chemical correlation with the derivatives of 21-nor-5α-cholan-20-ol, XVI and XXIV. The absolute configuration of alcohols XVI and XXIV was determined from the ratio of the yields in which they are formed during the reduction of ketone X and using the benzoate rule. To compounds XI-XVIII the configuration 20R and to compounds XIX-XXVI the configuration 20S has been assigned.

1-Substitution derivatives of 4-aryl-2,3-dibromo-1-naphthol

1981 ◽  
Vol 46 (9) ◽  
pp. 2116-2122 ◽  
Author(s):  
Jiří Křepelka ◽  
Jiří Roubík ◽  
Jiří Holubek
Keyword(s):  
Aqueous Medium ◽  
Ethyl Esters ◽  
Derivatives Of

Alkylation of 7-ethyl-4-(4-ethylphenyl)-2,3-dibromo-1-naphthol (I) with ethyl esters of ω-bromoalkanoic acids XX-XXIII in a non-aqueous medium gave the 1-substitution derivatives II, IV, VI and VIII which were hydrolyzed to the acids III, V, VII and IX. The acid III was used for syntheses of the esters X-XIII and amides XIV-XVIII. Compounds II-XVIII exhibited moderate antineoplastic effects in animals with transplanted tumours; best results were observed with the compound II.

Cleavage of the Epimines of 1,6-Anhydrohexoses with Fluoride Anion

2005 ◽  
Vol 70 (12) ◽  
pp. 2075-2085 ◽  
Author(s):  
Jiří Kroutil ◽  
Klára Jeništová
Keyword(s):  
Fluoride Anion ◽  
Ring Cleavage ◽  
Protecting Group ◽  
Reaction Conditions ◽  
Aziridine Ring ◽  
Cleavage Reactions ◽  
Derivatives Of ◽  
Fluoro Derivatives

Aziridine ring cleavage reactions of five N-nosylepimines (2-6) having D-talo, D-galacto, D-manno, and D-allo configurations with potassium hydrogendifluoride under various reaction conditions have been performed. The cleavage regioselectively afforded diaxial isomers of vicinal amino-fluoro derivatives of 1,6-anhydro-β-D-gluco- and mannopyranose 7-11 in 51-94% yields. Removal of 2-nitrobenzenesulfonyl protecting group with benzenethiol has been attempted in the case of compound 10.

scholarly journals Synthesis of New Derivatives of BEDT-TTF: Installation of Alkyl, Ethynyl, and Metal-Binding Side Chains and Formation of Tris(BEDT-TTF) Systems

2021 ◽  
Vol 7 (8) ◽  
pp. 110
Author(s):  
Songjie Yang ◽  
Matteo Zecchini ◽  
Andrew Brooks ◽  
Sara Krivickas ◽  
Desiree Dalligos ◽  
...  
Keyword(s):  
Metal Binding ◽  
Tricarboxylic Acid ◽  
Metal Salts ◽  
Side Chain ◽  
Side Chains ◽  
Ethynyl Group ◽  
X Ray ◽  
Transition Metal Salts ◽  
Alkyl Side Chains ◽  
Derivatives Of

The syntheses of new BEDT-TTF derivatives are described. These comprise BEDT-TTF with one ethynyl group (HC≡C-), with two (n-heptyl) or four (n-butyl) alkyl side chains, with two trans acetal (-CH(OMe)2) groups, with two trans aminomethyl (-CH2NH2) groups, and with an iminodiacetate (-CH2N(CH2CO2−)2 side chain. Three transition metal salts have been prepared from the latter donor, and their magnetic properties are reported. Three tris-donor systems are reported bearing three BEDT-TTF derivatives with ester links to a core derived from benzene-1,3,5-tricarboxylic acid. The stereochemistry and molecular structure of the donors are discussed. X-ray crystal structures of two BEDT-TTF donors are reported: one with two CH(OMe)2 groups and with one a -CH2N(CH2CO2Me)2 side chain.

scholarly journals Self-Supporting Hydrogels Based on Fmoc-Derivatized Cationic Hexapeptides for Potential Biomedical Applications

Biomedicines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 678
Author(s):  
Carlo Diaferia ◽  
Elisabetta Rosa ◽  
Enrico Gallo ◽  
Giovanni Smaldone ◽  
Mariano Stornaiuolo ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Supporting Cell ◽  
Diagnostic Tools ◽  
Cationic Peptides ◽  
Protecting Group ◽  
Synthetic Hydrogel ◽  
Acetyl Group ◽  
Biophysical Techniques ◽  
Fmoc Protecting Group ◽  
Derivatives Of

Peptide-based hydrogels (PHGs) are biocompatible materials suitable for biological, biomedical, and biotechnological applications, such as drug delivery and diagnostic tools for imaging. Recently, a novel class of synthetic hydrogel-forming amphiphilic cationic peptides (referred to as series K), containing an aliphatic region and a Lys residue, was proposed as a scaffold for bioprinting applications. Here, we report the synthesis of six analogues of the series K, in which the acetyl group at the N-terminus is replaced by aromatic portions, such as the Fmoc protecting group or the Fmoc-FF hydrogelator. The tendency of all peptides to self-assemble and to gel in aqueous solution was investigated using a set of biophysical techniques. The structural characterization pointed out that only the Fmoc-derivatives of series K keep their capability to gel. Among them, Fmoc-K3 hydrogel, which is the more rigid one (G’ = 2526 Pa), acts as potential material for tissue engineering, fully supporting cell adhesion, survival, and duplication. These results describe a gelification process, allowed only by the correct balancing among aggregation forces within the peptide sequences (e.g., van der Waals, hydrogen bonding, and π–π stacking).

scholarly journals Practical synthesis of 4-aryl- and 4-heteroarylazetidin-2-ones: applications in the synthesis of the Taxol® side chain

1994 ◽  
Vol 72 (10) ◽  
pp. 2131-2136 ◽  
Author(s):  
Allan W. Rey ◽  
Robert Droghini ◽  
James L. Douglas ◽  
Purushotham Vemishetti ◽  
Susan D. Boettger ◽  
...  
Keyword(s):  
Side Chain ◽  
Staudinger Reaction ◽  
Protecting Group ◽  
Practical Synthesis

A convenient, high-yielding procedure has been developed for the kilogram-scale synthesis of (±)-cis-3-acetoxy-4-phenylazetidin-2-one (3), a β-lactam that has been used in the semi-synthesis of Taxol®. The Staudinger reaction between hydrobenzamide (5) and acetoxyacetyl chloride in the presence of a base provided the α-benzylideneiminotoluene protected β-lactam 8. Without isolation of the intermediate β-lactam, the protecting group was removed under various reductive or hydrolytic conditions. The overall yields were about 80%. The synthesis of other (±)-cis-4-aryl- and 4-heteroarylazetidin-2-ones by this methodology has also been accomplished. These compounds are of value for the synthesis of 3′-Taxol® side-chain analogs and their preparation demonstrates the generality of this approach.

ChemInform Abstract: A GENERAL SYNTHESIS OF SIDE CHAIN DERIVATIVES OF Δ9-THC

1978 ◽  
Vol 9 (12) ◽  
Author(s):  
C. G. PITT ◽  
H. H. SELTZMAN ◽  
Y. SAYED ◽  
C. E. JUN. TWINE ◽  
D. L. WILLIAMS
Keyword(s):  
Side Chain ◽  
Derivatives Of ◽  
General Synthesis

New 4-Hydroxypyridine and 4-Hydroxyquinoline Derivatives as Inhibitors of NADH-ubiquinone Reductase in the Respiratory Chain

1989 ◽  
Vol 44 (7-8) ◽  
pp. 609-616 ◽  
Author(s):  
Kun Hoe Chung ◽  
Kwang Yun Cho ◽  
Yasuko Asami ◽  
Nobutaka Takahashi ◽  
Shigeo Yoshida
Keyword(s):  
Electron Transport ◽  
Respiratory Chain ◽  
Side Chain ◽  
Pyridine Derivatives ◽  
Transport Function ◽  
Optimal Length ◽  
Structure Activity ◽  
Membrane Effect ◽  
Relationship Of ◽  
Derivatives Of

Many derivatives of 2,3-dim ethoxy-4-hydroxypyridine, which were designed from examination of the structure-activity relationship of piericidins, were tested for inhibition of NADH-UQ reductase. The lipophilic side chain of those compounds was indicated to be a key part for activity and its optimal length was conjectured. By the use of two different phases of assay material, intact mitochondria and submitochondria, the size of a membrane effect was shown to depend on the structure of the side chain. 4-Hydroxyquinoline derivatives were also tested for an analogous role in relation to the electron transport function of menaquinone, and they were proven to be inhibitors of NADH-UQ reductase as good as the pyridine derivatives.

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