Phenolic Mannich Bases Research Articles

ChemInform Abstract: AN EFFICIENT METHOD FOR THE CONVERSION OF PHENOLIC MANNICH BASES TO C‐METHYLATED PHENOLS. SYNTHESIS OF 3,6‐DIMETHYLCATECHOL

AbstractDas als Zwischenprodukt benötigte Brenzcatechin‐Derivat (VI) kann auf dem skizzierten Weg über das Mannich‐Produkt (III), dessen Umsetzung mit Acetanhydrid zum Tetraacetat (IV), Hydrogenolyse zum Bis‐acetat (V) und anschließende Methanolyse hergestellt werden.

Selective Synthesis of Phenolic Mannich Bases under Solid-Liquid Phase Transfer Conditions

Aminomethylation de phenol, alkylphenols, hydroxy-4-acetophenone et -benzoate de methyle et de naphtols-2 par reaction avec des halogenures de (dimethyl methylene) ammonium en presence de K 2 CO 3 dans le toluene ou le dichloromethane

ChemInform Abstract: SYNTHESIS OF DIHYDROBENZOFURANS FROM PHENOLIC MANNICH BASES AND THEIR QUATERNIZED DERIVATIVES

Chemischer InformationsdienstVolume 13, Issue 24 Heterocyclic Compounds ChemInform Abstract: SYNTHESIS OF DIHYDROBENZOFURANS FROM PHENOLIC MANNICH BASES AND THEIR QUATERNIZED DERIVATIVES A. BLADE-FONT, A. BLADE-FONTSearch for more papers by this authorT. DE MAS ROCABAYERA, T. DE MAS ROCABAYERASearch for more papers by this author A. BLADE-FONT, A. BLADE-FONTSearch for more papers by this authorT. DE MAS ROCABAYERA, T. DE MAS ROCABAYERASearch for more papers by this author First published: June 15, 1982 https://doi.org/10.1002/chin.198224202AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume13, Issue24June 15, 1982 RelatedInformation

Synthesis of dihydrobenzofurans from phenolic mannich bases and their quaternized derivatives

Reaction of dimethylsulphoxonium methylide with quaternized derivatives of phenolic Mannich bases, and in certain cases with the bases themselves, constitutes a useful synthesis of dihydrobenzofurans. On the other hand treatment of those same quaternized derivatives with diazomethane may be a useful alternative procedure for the preparation of coumarans with base-sensitive groups.

An Efficient Method for the Conversion of Phenolic Mannich Bases to C-Methylated Phenols. Synthesis of 3,6-Dimethylcatechol

An Efficient Method for the Conversion of Phenolic Mannich Bases to C-Methylated Phenols. Synthesis of 3,6-Dimethylcatechol

ChemInform Abstract: CHEMICAL DEGRADATION OF LASALOCID. (A). THE MANNICH REACTION. (B) BAEYER‐VILLIGER OXIDATION OF THE RETRO‐ALDOL KETONE

Abstract1. Mannich‐Reaktion von Lasalocid (I) mit den Komponenten (II) und (III) (Paraformaldehyd) gibt die Verbindung (IV), die sich (zur Struktursicherung) in mehreren Schritten wieder in (I) überführen läßt. Aus (IV) sind die Sulfide (VIa) (antihypertensiv wirksam) bzw. (VIb) erhältlich.

Far-infrared absorption in some phenolic mannich bases

Submillimetre absorption measurements are reported for six phenolic Mannich bases in the region 20–90 cm −1 at room temperature. Three distinct absorption peaks are observed around 45, 65 and 85 cm −1 for all these compounds. Based on the present data and dielectric loss studies the origin of the observed FIR absorption peaks is discussed.

Chemical Degradation of Lasalocid: (A) The Mannich reaction (B) Baeyer‐Villiger oxidation of the retro‐aldol ketone

AbstractUnder Mannich reaction conditions (diethylamine and formaldehyde in toluene under reflux) lasalocid (1) undergoes a unique transformation in which the carboxyl group is replaced by a diethylaminomethyl group. The resulting Mannich base 2 was converted back to lasalocid, proving that none of the other chemical and stereochemical features of the molecule were disturbed. Like other phenolic Mannich bases, the one derived from lasalocid readily alkylated mercaptans.The known thermal and base‐induced retro‐aldol degradations of lasalocid both produce a ketone fragment 9 containing the cyclic ether units. Baeyer‐Villiger oxidation of this ketone afforded a carboxylic acid fragment which still contained these ether units. The normal regiochemistry involved in oxidizing this ketone (RCH2COCHR′R″ type) was cleanly reversed by first converting it into the hydroxymethylidene derivative 10.

ChemInform Abstract: DIELECTRIC RELAXATION STUDIES. II. PHENOLIC MANNICH BASES IN DILUTE SOLUTION

The dielectric relaxation processes in phenolic Mannich bases have been investigated by measuring the dielectric permittivity and loss in dilute solutions of benzene at three different microwave frequencies at 30°, 45°, and 60 °C. Results are analyzed in terms of Cole–Cole arc plots and two distinct relaxation times. The results establish the intramolecular hydrogen bonding of the –OH group. The overall molecular relaxation appears to be the predominant mechanism in these substituted phenols. Activation parameters have been calculated assuming dielectric relaxation to be an Eyring‐type rate process.

Biologically active Mannich bases derived from nitroxoline.

A series of compounds with various basic side chains were derived from 5-nitro-8-hydroxyquinoline (nitroxoline). Aminomethylation of nitroxoline led exclusively to the formation of o-substituted phenolic Mannich bases. Depending on the kind of the primary or secondary amine participating in the Mannich reaction differently substituted compounds were prepared in order to study the influence of the basic side chain on their biological activity. The compound with N-bis(2-hydroxyethyl)amino group exhibited the highest mitodepressant activity determined in a phyto test on Lepidium sativum L. Preliminary test for antibacterial and antifungal activities using standard test microorganisms indicate rather strong antimicrobial properties of several synthesized compounds.

Dielectric relaxation studies. II. Phenolic Mannich bases in dilute solution

The dielectric relaxation processes in phenolic Mannich bases have been investigated by measuring the dielectric permittivity and loss in dilute solutions of benzene at three different microwave frequencies at 30°, 45°, and 60 °C. Results are analyzed in terms of Cole–Cole arc plots and two distinct relaxation times. The results establish the intramolecular hydrogen bonding of the –OH group. The overall molecular relaxation appears to be the predominant mechanism in these substituted phenols. Activation parameters have been calculated assuming dielectric relaxation to be an Eyring-type rate process.

Additions and Corrections - 2,4-Diamino-5-benzylpyrimidines and Analogues as Antibacterial Agents. 3. C-Benzylation of Aminopyridines with Phenolic Mannich Bases. Synthesis of 1- and 3-Deaza Analogues of Trimethoprom.

Additions and Corrections - 2,4-Diamino-5-benzylpyrimidines and Analogues as Antibacterial Agents. 3. C-Benzylation of Aminopyridines with Phenolic Mannich Bases. Synthesis of 1- and 3-Deaza Analogues of Trimethoprom.

ChemInform Abstract: 2,4‐DIAMINO‐5‐BENZYLPYRIMIDINES AND ANALOGS AS ANTIBACTERIAL AGENTS. 3. C‐BENZYLATION OF AMINOPYRIDINES WITH PHENOLIC MANNICH BASES. SYNTHESIS OF 1‐ AND 3‐DEAZA ANALOGS OF TRIMETHOPRIM

AbstractDas Diaminopyridin (II) wird mit den phenolischen Mannich‐Basen (I) zu den Verbindungen (III)‐(Va) benzyliert.

2,4-Diamino-5-benzylpyrimidines and analogues as antibacterial agents. 3. C-Benzylation of aminopyridines with phenolic Mannich bases. Synthesis of 1- and 3-deaza analogues of trimethoprim.

Electrophilic substitution of 2,4-diaminopyridine by 2,6-disubstituted -4-[(N,N-dimethylamino)methyl]phenols and by halogens (bromine and fluorine) produces 3-benzyl and 3-halo derivatives, plus a small amount of disubstitution at the 3,5 positions. Treatment of a 2,4-diamino-3-halopyridine with phenolic Mannich bases gives 5- and N-benzylation. 2,4-Diamino-3-bromo-5-(4-hydroxy-3,5-dimethoxybenzyl)pyridine was methylated on the phenolic group in good yield and dehalogenated to produce 3-deazatrimethoprim [2,4-diamino-5-(3,4,5-trimethoxybenzyl)pyridine]. This compound is about 300-fold less active as an inhibitor of Eschericia coli dihydrofolate reductase than is trimethoprim. 2,6-Diaminopyridine is very readily dibenzylated at the 3,5 positions as well as on an amino group, by a phenolic Mannich base; use of a fourfold excess of the pyridine provided a 3-benzylated 2,6-diaminopyridine in 50% yield; this was inactive as an inhibitor of dihydrofolate reductase at 10(-4) M. 2-Amino- and 4-aminopyridines do not produce C-benzylated products under the conditions reported here.

2,4-Diamino-5-benzylpyrimidines and analogs as antibacterial agents. 2. C-Alkylation of pyrimidines with Mannich bases and application to the synthesis of trimethoprim and analogs

A new route to 5-(p-hydroxybenzyl)pyrimidines has been developed which utilizes phenolic Mannich bases plus pyrimidines containing at least two activating groups. The products can be alkylated on the phenolic oxygen or on the pyrimidine N-1 atom, depending on conditions. This method has been used to prepare trimethoprim, a broad-spectrum antibacterial agent, starting from 2,4-diaminopyrimidine and 2,6-dimethoxyphenol.

Studies in phenolic mannich bases - reaction with acetylenes

3-Formyl, 3-benzoyl and 2,3-dibenzoyl-4H-Chromenes have been synthesised by the reaction of phenolic Mannich bases with electron-deficient acetylenic systems.

Dielectric relaxation studies in some phenolic mannich bases

The dielectric permittivity (ε′) and loss factor (ε″) of six phenolic Mannich bases are reported at cm and mm wavelengths in the temperature range 30–70°C. The analysis of dielectric data in terms of Cole–Cole arc and multiple relaxation times reveal that the overall molecular rotation appears to be the predominant relaxation mechanism in these substituted phenols. The activation parameters have been calculated assuming dielectric relaxation to be a rate process.

Interaction of diethyl thiophosphite with phenolic mannich bases

1. The interaction of phenolic Mannich bases with diethyl thiophosphite forms o-hydroxybenzylthiophosphonates, which undergo Pishchimuka rearrangement. Diethyl thiophosphite here disproportionates by reaction with diethylamine to form NN-diethyl O-ethyl amidophosphite and diethyl phosphite. 2. α-Substituted methyldiethylamines react with diethyl thiophosphite to form OO-diethyl NN-diethylaminomethylthiophosphonate.

The use of amino acids in the mannich reaction

AbstractAmino acids have been found to participate as the amine component in the Mannich reaction with both ketones and phenols. The phenolic Mannich bases may be cyclized with sulfuric acid to 1,2‐dihydro‐4(3/H)isoquinolones. In the presence of thionyl chloride the same Mannich bases undergo lactonization to benz[f]‐1,4‐oxazepin‐4(3H)ones.

Formation of alkoxyphosphoranes in reaction of substituted o-aminomethylphenols with trialkyl phosphites

1. The formation of stable alkoxyphosphoranes is observed when a phenolic Mannich base, containing o-substituents in the benzene ring, is reacted with trialkyl phosphites. 2. The properties of the alkoxyphosphoranes were studied: hydrolysis, thermal isomerization, and reaction with compounds that contain a labile hydrogen atom. It was shown that these reactions proceed with a rupture of the phosphorane ring.