Reactions of Alkylthio Derivatives of Aluminum with Aldehydes, Ketones, and Olefins

1971 ◽  
Vol 49 (18) ◽  
pp. 2983-2989 ◽  
Author(s):  
J. M. Lalancette ◽  
Y. Beauregard ◽  
M. Bhéreur
Keyword(s):  
Double Bond ◽  
Allylic Substitution ◽  
Acetyl Group ◽  
Derivatives Of

The preparation of ((CH3)2CHS)2AlCH3 and (t-CaH9S)2AlCH3 is reported. The reactions of (RS)2AlCH3 (R = CH3, (CH3)2CH, t-C4H9) with ketones give aldol condensations leading to the corresponding conjugated ketones, with the acetyl group R—CO—CH3; with other ketones, a mixture of thioacetal and enolthioether is obtained. With aldehydes, a mixture of thioacetal and enolthioether is observed. With olefins there is an addition of two RS groups on the site of the double bond, with a small percentage of allylic substitution. With conjugated ketone, the saturated ketone is obtained with the alkylthio group in β position. All those reactions proceed with good yields and appear quite general.

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 Oxepinamide F biosynthesis involves enzymatic d-aminoacyl epimerization, 3H-oxepin formation, and hydroxylation induced double bond migration

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Liujuan Zheng ◽  
Haowen Wang ◽  
Aili Fan ◽  
Shu-Ming Li
Keyword(s):  
Cytochrome P450 ◽  
Double Bond ◽  
Biosynthetic Pathway ◽  
Hydroxyl Group ◽  
Cytochrome P450 Enzyme ◽  
Double Bond Migration ◽  
Feeding Experiments ◽  
Aspergillus Ustus ◽  
P450 Enzyme ◽  
Derivatives Of

Abstract Oxepinamides are derivatives of anthranilyl-containing tripeptides and share an oxepin ring and a fused pyrimidinone moiety. To the best of our knowledge, no studies have been reported on the elucidation of an oxepinamide biosynthetic pathway and conversion of a quinazolinone to a pyrimidinone-fused 1H-oxepin framework by a cytochrome P450 enzyme in fungal natural product biosynthesis. Here we report the isolation of oxepinamide F from Aspergillus ustus and identification of its biosynthetic pathway by gene deletion, heterologous expression, feeding experiments, and enzyme assays. The nonribosomal peptide synthase (NRPS) OpaA assembles the quinazolinone core with d-Phe incorporation. The cytochrome P450 enzyme OpaB catalyzes alone the oxepin ring formation. The flavoenzyme OpaC installs subsequently one hydroxyl group at the oxepin ring, accompanied by double bond migration. The epimerase OpaE changes the d-Phe residue back to l-form, which is essential for the final methylation by OpaF.

scholarly journals Synthesis and Olfactory Characteristics of Hydroxyether Derivatives of Methyl Eugenol

2020 ◽  
Vol 24 (9) ◽  
pp. 1503-1507
Author(s):  
S.O. Okopi ◽  
L.M. Affiku
Keyword(s):  
Double Bond ◽  
Essential Oils ◽  
Plant Species ◽  
Chemical Transformation ◽  
Structural Modification ◽  
Methyl Eugenol ◽  
Naturally Occurring ◽  
Relationship Of ◽  
Derivatives Of ◽  
Functional Alteration

Methyl eugenol is a naturally occurring substance found in the essential oils of several plant species. It is a cheap and abundant material with a rather limited interest as perfuming ingredient. This research investigated the structure-odour relationship of methyl eugenol and its derivatives, focusing on the chemical transformation of the double bond to hydroxyether derivatives in a controlled manner. Two derivatives 2-(4-ethyl- 3-methoxybenzyl)oxirane (68.8% yield) and 1-(3,4-dimethoxyphenyl)-3-ethoxypropan-2-ol (63.58% yield), were synthesized from methyl eugenol. This research found that the odour characteristic of 2-(4-ethyl-3-methoxybenzyl)oxirane[floral, fresh, slight lime and sweet]compounds, is clearly different from the odours of the 1-(3,4-dimethoxyphenyl)-3-ethoxypropan-2-ol [Glue-like, pungent, and Caramel-like]. It is evident from our observations that double bond substitution and functional alteration of the methyl eugenol modifies the perceived odour of methyl eugenol  derivative. Thus, structural modification overall led to an increase in odour potency. Keywords: Fragrance, Methly-Eugenol, Ether, Olfactory characteristic, Epoxidation.

Über Derivate des Hydrazins, VII Zur Reaktivität von Bis(trimethylsilyl)aminoisocyanid / On Derivatives of Hydrazine, VII Reactivity of Bis(trimethylsilyl)aminoisocyanide

1977 ◽  
Vol 32 (9) ◽  
pp. 1003-1009 ◽  
Author(s):  
Nils Wiberg ◽  
Gerhard Hübler
Keyword(s):  
Double Bond ◽  
Oxidation State ◽  
Ring Cleavage ◽  
Reaction Paths ◽  
Stable Compound ◽  
Oxidizing Agents ◽  
Formal Oxidation State ◽  
Double Bond System ◽  
Bond System ◽  
Derivatives Of

The chemistry of bis(trimethylsilyl)aminoisocyanide (1) is determined by three reactive centres of the system : the hydrolyzable Si–N-bond, the oxidizable carbon in the formal oxidation state two, the additionable double bond system. Reactions of the oxygen stable compound 1 with halogens X2 or sulfenyl halides RSX as oxidizing agents gives compounds of type (Me3Si)2NNCX2 or (Me3Si)2NNCX(SR). Heterocumulenes such as CO2, CS2, RNCS (R = (Me3Si)2N), SO2 add to 1, leading to heterocycles, which decompose at higher temperatures by ring cleavage. With other heterocumulenes such as PhNCO, Me3SiNSO, Me3SiNSNSiMe3 products are found, the formation of which could be explained by reaction paths including the building and cleavage of heterocycles.

Acetal Formation Facilitated in 2-Hydroxyaryl Aldehydes by Intramolecular Acyl Group Transfer

1986 ◽  
Vol 39 (11) ◽  
pp. 1747 ◽  
Author(s):  
AJ Liepa ◽  
AJ Liepa ◽  
TC Morton ◽  
TC Morton
Keyword(s):  
Acyl Transfer ◽  
Reaction Conditions ◽  
Group Transfer ◽  
Acetyl Group ◽  
Derivatives Of ◽  
Acyl Derivatives ◽  
Mechanism Of The Reaction

Convenient preparations of synthetically useful acetals, a dithioacetal and an oxathiolan from the 2-acyl derivatives of 2-hydroxyaryl aldehydes under basic conditions are described. The mildness of the reaction conditions is illustrated by the formation of an ethoxycarbonyl -substituted dioxolan . The reaction is dependent upon an intramolecular acetyl group transfer and the mechanism of the reaction is discussed. Some broader implications of this type of acyl transfer are discussed.

scholarly journals The Synthesis of the Locating Substitution Derivatives of Chitosan by Click Reaction at the 6-Position of Chitin

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Yu Chen ◽  
Yanchun Ye ◽  
Yanyan Jing ◽  
YuanYuan Gao ◽  
Yanwen Guo ◽  
...  
Keyword(s):  
Nucleophilic Substitution ◽  
High Efficiency ◽  
Click Reaction ◽  
Macrocyclic Compound ◽  
Optimum Conditions ◽  
Structures And Properties ◽  
Acetyl Group ◽  
Novel Method ◽  
Derivatives Of

A novel method to prepare the macrocyclic compound locating substitution derivatives of chitosan was investigated, by using cyclodextrin as the model of macrocyclic compound. The method combines the advantages of activated 6-OH of chitin and high efficiency of click reaction. Chitin C6-OHp-toluenesulfonate (CTN-6-OTs) was generated and subsequently transferred to chitin C6-N3via nucleophilic substitution. Afterwards,β-cyclodextrin was immobilized at 6-OH of chitin via click reaction to afford CTN-6-CD. Ultimately, CTS-6-CD was obtained by removing the acetyl group of chitin unit. The structures and properties of these products were characterized by FTIR, TG, and XRD, respectively. It was found that CTN-6-CD synthesized at the optimum conditions has an immobilized loading of1.6126×10-4 mol/g and that of the corresponding CTS-6-CD, generated by removal of the acetyl group, was1.6891×10-4 mol/g.

THE HYDROLYSIS OF p-ACETOXYPHENYLETHYLAMINES BY INSECT CHOLINESTERASE

1958 ◽  
Vol 36 (1) ◽  
pp. 145-152
Author(s):  
L. S. Wolfe ◽  
G. D. Thorn
Keyword(s):  
Human Serum ◽  
Carbonyl Oxygen ◽  
Rectus Abdominis ◽  
Hydrolysis Rate ◽  
Rectus Abdominis Muscle ◽  
Oxygen Separation ◽  
Bovine Erythrocyte ◽  
Acetyl Group ◽  
Hydrolysis Of ◽  
Derivatives Of

The synthesis of the acetyl derivatives of tyramine and hordenine is described. The O-monoacetyl derivatives are hydrolyzed at significant rates by bovine erythrocyte cholinesterase, human serum, and fly head cholinesterase despite a nitrogen to carbonyl oxygen separation approximately twice that of acetylcholine. The pS-activity relationships, when O-acetyltyramine and acetylcholine were substrates for fly head cholinesterase, were similar, but the hydrolysis rate of O-acetyltyramine was much higher than that of acetylcholine. N-Acetylation of the O-acetyl compounds reduced the hydrolysis rate. None of the cholinesterases removed the acetyl group attached to nitrogen. The pI-activity relationships with the inhibitors Nu-683, Nu-1250, TEPP, and eserine showed that the hydrolysis of p-acetoxyphenylethylamine derivatives and acetylcholine by fly head preparations was accomplished by the same cholinesterase and not by aromatic or aliesterases. O-Acetylation of hordenine methiodide destroyed its nicotinelike action on frog rectus abdominis muscle.

Structure and Content of Dicyclopentadiene in Ethylene Propylene Dicyclopentadiene Terpolymers

1967 ◽  
Vol 40 (2) ◽  
pp. 563-568
Author(s):  
R. J. de Kock ◽  
A. Veermans
Keyword(s):  
Double Bond ◽  
Polymer Chain ◽  
Spectroscopic Methods ◽  
Double Bonds ◽  
Model Compounds ◽  
Ethylene Propylene ◽  
Infrared Spectroscopic ◽  
Polymerization Mixture ◽  
Derivatives Of

Abstract With the aid of model compounds—derivatives of endo- and exo-dicyclopentadiene—it has been established that a) the 9, 10-double bond (the double bond in the norbornane ring) is involved in the polymerization of dicyclopentadiene with ethylene and propylene, b) dicyclopentadiene, present in the polymerization mixture in the endo-configuration, occurs in the exo-configuration in the polymer chain. The same model compounds enable the dicyclopentadiene content of ethylene propylene dicyclopentadiene terpolymers to be determined by infrared spectroscopic methods. Use is made of the 3045 cm−1 band, which is characteristic of endo-cyclic double bonds in five-membered rings.

ÉTUDES SUR LA SYNTHÈSE DE L’HYDROXYPROLINE À PARTIR DE DÉRIVÉS DE L’ACIDE 2-AMINO-4-PENTÈNOÏQUE

1956 ◽  
Vol 34 (4) ◽  
pp. 502-514 ◽  
Author(s):  
Roger Gaudry ◽  
Louis Berlinguet ◽  
André Langis ◽  
Gérard Paris
Keyword(s):  
Double Bond ◽  
Acid Hydrolysis ◽  
Malonic Acid ◽  
Systematic Investigation ◽  
Carboxyl Group ◽  
Reaction Products ◽  
Pentanoic Acid ◽  
Copper Salts ◽  
Halogenation Reaction ◽  
Derivatives Of

A systematic investigation of the synthesis of 4-hydroxy-DL-proline and 2-amino-4-dihydroxyvaleric acid has been made, starting from the following derivatives of 2-amino-4-pentenoic acid: ethyl allylacetamidomalonate, ethyl allylacetamidocyanoacetate, 2-phthalimidopentenoic acid, allylacetamido-malonic acid, acetylallylglycine, 5-allylhydantoin, and 3-phenyl-5-allylhydantoin. Chlorine or bromine was added to the double bond of these compounds, and the reaction products were either derivatives of 5-halogenated-4-valerolactones or derivatives of 4,5-dihalogenated pentanoic acids, depending on whether the carboxyl group of the pentanoic acid was free or not when the halogenation reaction was carried out. Acid hydrolysis followed by treatment with barium hydroxide always gave mixtures, in different ratio, of 4-hydroxy-DL-proline and 2-amino-4,5-dihydroxyvaleric acid which were analyzed and isolated as the copper salts. In the case of 5-(2,3-dibromopropyl)hydantoin and 3-phenyl-5-(2,3-dibromopropyl)hydantoin, no cyclization could be obtained.

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