scholarly journals ACID CATALYSIS OF THE FORMALDEHYDE CONDENSATION REACTION FOR SENSITIVE HISTOCHEMICAL DEMONSTRATION OF TRYPTAMINES AND 3-METHOXYLATED PHENYLETHYLAMINES

1970 ◽  
Vol 18 (11) ◽  
pp. 794-802 ◽  
Author(s):  
ANDERS BJÖRKLUND ◽  
ULF STENEVI
Keyword(s):  
Acid Catalysis ◽  
Condensation Reaction ◽  
Fluorescence Yield ◽  
Histochemical Demonstration ◽  
Formaldehyde Treatment ◽  
Hcl Gas ◽  
Fluorescent Products ◽  
Acid Catalyzed ◽  
Gaseous Formaldehyde ◽  
Related Compounds

Hydrochloric acid catalyzes the formation of fluorophores in the histochemical condensation reaction between gaseous formaldehyde and certain phenylethylamines and indolylethylamines. Thus, when the formaldehyde reaction is carried out in the presence of minute amounts of HCl gas, 3-methoxy-4-hydroxyphenylethylamine, 3,4-dimethoxyphenylalanine and tryptamine displayed a fluorescence yield approximately 20-200 times higher than that obtained after standard formaldehyde treatment in normal air ( i.e., the conditions of the Falck-Hillarp method). This fluorescence intensity was nearly twice as high as that obtained from noradrenaline and dopamine under the standard conditions. The results indicate that the acid catalyzes the first step of the histochemical reaction, i.e., the Pictet-Spengler condensation reaction. In this step low fluorescent tetrahydroisoquinolines and tetrahydro-β-carbolines are formed, which are subsequently dehydrogenated to strongly fluorescent products. Low reactive aromatic amines and amino acids, such as phenylalanine, tyrosine, amphetamine and melatonin, gave no or only very low visible fluorescence after this treatment. Thus, the acid-catalyzed histochemical formaldehyde reaction described in this paper exhibits a good specificity for indolylethylamines and 3-hydroxylated or 3-methoxylated phenylethylamines and will also allow the distinction between these structurally related compounds on the basis of their reactivity in the condensation reaction.

scholarly journals ACID CATALYSIS OF THE FORMALDEHYDE CONDENSATION REACTION FOR A SENSITIVE HISTOCHEMICAL DEMONSTRATION OF TRYPTAMINES AND 3-METHOXYLATED PHENYLETHYLAMINES 2. CHARACTERIZATION OF AMINE FLUOROPHORES AND APPLICATION TO TISSUES

1971 ◽  
Vol 19 (5) ◽  
pp. 286-298 ◽  
Author(s):  
ANDERS BJÖRKLUND ◽  
ANDERS NOBIN ◽  
ULF STENEVI
Keyword(s):  
Fluorescence Spectra ◽  
Condensation Reaction ◽  
Histochemical Demonstration ◽  
Freeze Dried ◽  
Highly Sensitive ◽  
Hcl Gas ◽  
Fluorescent Products ◽  
Acid Catalyzed ◽  
Cryostat Sections

A histochemical fluorescence method is presented in which a controlled activation of the condensation reaction between formaldehyde and certain aromatic monoamines is achieved by the introduction of minute amounts of HCl gas in the formaldehyde reaction vessel. In this way, not only highly reactive catecholamines and 5-hydroxytryptamine but also less reactive compounds, such as tryptamine, 5-methoxytryptamine and 3-methoxylated phenylethylamines which give only weak fluorescence in the noncatalyzed formaldehyde reaction, can be converted into intensely fluorescent products. The acid-catalyzed formaldehyde treatment proved to be a highly sensitive technique for the demonstration of these various monoamines in freeze-dried tissues. The reaction thus proceeded without any observable dislocation of the substances from their cellular stores and the resulting fluorophores were well visible against an essentially dark background. The procedure was successfully, and equally well, applied to whole freeze-dried tissue pieces, to paraffin sections of freeze-dried specimens and to freeze-dried cryostat sections. The fluorescence properties of a large number of phenylethylamine and indolylethylamine fluorophores, formed in the acid-catalyzed formaldehyde reaction, have been investigated microspectrofluorometrically in models and in freeze-dried tissues. The fluorescence spectra of the amine fluorophores were consistent and fully reproducible, making possible the accurate characterization of cellular monoamines with this method.

scholarly journals MICROFLUORIMETRIC STUDIES ON THE FORMALDEHYDE-INDUCED FLUORESCENCE OF NORADRENALINE IN ADRENERGIC NERVES OF RAT IRIS

1969 ◽  
Vol 17 (11) ◽  
pp. 714-723 ◽  
Author(s):  
GÖSTA JONSSON
Keyword(s):  
Fluorescence Intensity ◽  
Linear Part ◽  
Fluorescence Yield ◽  
Histochemical Demonstration ◽  
Adrenergic Nerves ◽  
Noradrenaline Concentration ◽  
Amine Storage ◽  
Rat Iris ◽  
Gaseous Formaldehyde

The fluorescence concentration relationship of formaldehyde-induced fluorescence of noradrenaline in adrenergic nerves of rat iris was investigated by the use of isotope and microfluorimetric techniques. The irides first were depleted of their endogenous stores of noradrenaline either by reserpine or by the methylester of α-methyl- p-tyrosine (H 44/68) and then were incubated in vitro in a physiologic medium containing 3H-noradrenaline for partial replenishment of the nerves of their transmitter. The incubated irides were prepared as whole amounts and were exposed to gaseous formaldehyde for histochemical demonstration of noradrenaline. Microfluorimetric and isotope measurements were performed on the same preparations. The fluorescence intensity was found to be proportional to the noradrenaline concentration up to a value corresponding to 30-40% of the endogenous level, above which a concentration-dependent quenching of the fluorescence occurred. In the linear part of the relation, it was possible to perform fairly safe estimations of the fluorescence intensity by eye, but, if the nerves contained more than 40% of the endogenous content, usually no differentiation could be made, probably as a result of quenching effects. The quenching appears somewhat earlier and the relative fluorescence yield is lower when noradrenaline is stored in the intraneuronal amine storage granules, compared with the situation when the amine mainly is distributed extragranularly in the axoplasm. It can be concluded that, if changes in fluorescence intensity as compared with the control are observed, this reflects true changes in amine concentrations, but changes in amine concentration may escape detection when the concentration of amine is so high that quenching occurs.

scholarly journals FLUORESCENCE METHODS FOR THE HISTOCHEMICAL DEMONSTRATION OF MONOAMINES: 4. HISTOCHEMICAL DIFFERENTIATION BETWEEN DOPAMINE AND NORADRENALINE IN MODELS

1965 ◽  
Vol 13 (6) ◽  
pp. 484-487 ◽  
Author(s):  
HANS CORRODI ◽  
GÖSTA JONSSON
Keyword(s):  
Hydroxy Group ◽  
Sodium Borohydride ◽  
Thionyl Chloride ◽  
Emission Spectra ◽  
Histochemical Demonstration ◽  
Protein Layer ◽  
Fluorescence Methods ◽  
Fluorescent Products ◽  
Gaseous Formaldehyde

If primary catecholamines e.g. dopamine and noradrenaline in a dried protein layer are exposed to gaseous formaldehyde, they are converted to intensely fluorescent 6,7-dihydroxy-3,4-dihydroisoquinolines. This reaction can be used for the histochemical demonstration of these amines. The fluorescent products of dopamine and noradrenaline have practically identidal activation and emission spectra. The 4,6,7-trihydroxy-3,4-dihydroisoquinoline formed from noradrenaline has, however, a labile hydroxy group at 4-position which can be easily split off. This dehydration to the fully aromatic 6,7-dihydroxyisoquinoline was found to take place readily in a dried protein layer by treatment with thionyl chloride gas at 50°C. The isoquinoline shows other flurorescence characteristics than the 3,4-dihydroisoquinolines and is not reduced by sodium borohydride. A direct histochemical differentiation between dopamine and noradrenaline is thus possible.

Antiaminic agents derived from thieno[2,3-c]-2-benzothiepin: 4-(1-Methyl-4-piperidylidene)-4,9-dihydrothieno[2,3-c]-2-benzothiepin and some related compounds

1983 ◽  
Vol 48 (2) ◽  
pp. 623-641 ◽  
Author(s):  
Zdeněk Polívka ◽  
Miroslav Rajšner ◽  
Jan Metyš ◽  
Jiří Holubek ◽  
Emil Svátek ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Sulfuric Acid ◽  
Title Compound ◽  
Amino Alcohol ◽  
Hydrogen Sulfate ◽  
Geometric Isomers ◽  
Pure Alcohol ◽  
Acid Catalyzed ◽  
Anticataleptic Activity ◽  
Related Compounds

In the reaction of thieno[2,3c]-2-benzothiepin-4(9H)-one (VI) with 1-methyl-4-piperidylmagnesium chloride 7-(1-methyl-4-piperidyl)thieno[2,3-c]-2-benzothiepin-4(9H)-one (VIII) is formed in addition to the expected amino alcohol VII. The title compound I was obtained by the acid catalyzed dehydration of the pure alcohol VII. Compound I (pipethiadene) has outstanding antihistamine, antiserotonin, antireserpine and anticataleptic activity and was recommended to clinical trials as a potential antimigraine agent. For pharmacokinetic and metabolic studies there were prepared the NC2H3 analogue of pipethiadene IV and further, as potential metabolites, the demethyl analogue III, S-oxide X, demethyl S-oxide XI, N-oxide XIII and N,S-dioxide XIV. The Witting reaction of the ketone VI with 3-dimethylaminopropylidenetriphenylphosphorane resulted in a mixture of geometric isomers of 4-(3-dimethylamino-propylidene)-4,9-dihydrothieno[2,3-c]-2-benzothiepin with the strongly predominating Z-isomer XVI which was isolated from the mixture by crystallization of the hydrogen maleate. The mixture with the predominating Z-isomer XVI was converted by the treatment with 80% sulfuric acid and dilution with water to a mixture with the predominating E-isomer XV (dithiadene) which was isolated by crystallization of the hydrogen sulfate. Some further new thieno[2,3-c]-2-benzothiepin derivatives were synthesized as potential intermediates.

Acid-catalyzed Solvolysis of Isonitriles. I

1971 ◽  
Vol 49 (14) ◽  
pp. 2455-2459 ◽  
Author(s):  
Y. Y. Lim ◽  
A. R. Stein
Keyword(s):  
Formic Acid ◽  
Acid Catalysis ◽  
Hydrolysis Product ◽  
Rate Dependence ◽  
Linear Rate ◽  
First Order ◽  
Methyl Amine ◽  
Acid Catalyzed ◽  
Pseudo First Order ◽  
Hydrolysis Of

The acid-catalyzed hydrolysis of methyl isonitrile has been examined. The initial hydrolysis product is N-methylformamide which is further hydrolyzed to methyl amine and formic acid at a much slower rate. The hydrolysis to N-methylformamide is pseudo-first order in methyl isonitrile and shows a linear rate dependence on concentration of general (buffer) acid at fixed pH. The significance of general acid-catalysis in terms of the mechanism of the hydrolysis is considered and taken as evidence for carbon protonation rather than nitrogen protonation as the initiating step.

Brønsted acid-catalyzed 1,2-fluorine migration with fluoroepoxides

2015 ◽  
Vol 44 (45) ◽  
pp. 19636-19641 ◽  
Author(s):  
Tao Luo ◽  
Rui Zhang ◽  
Xiao Shen ◽  
Wei Zhang ◽  
Chuanfa Ni ◽  
...  
Keyword(s):  
Fluorine Atom ◽  
Acid Catalysis ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Atom Economy ◽  
Mild Conditions ◽  
Brönsted Acid ◽  
Acid Catalyzed ◽  
Bronsted Acid Catalysis

An efficient 1,2-fluorine migration reaction was realized under Brønsted acid catalysis in the absence of an external fluorinating source. The high fluorine atom economy and very mild conditions make this reaction a promising protocol for the construction of the C–F bond.

Acid-Catalyzed Condensation Reaction of Phenylsilanetriol: Unexpected Formation of cis,trans-1,3,5-Trihydroxy-1,3,5-triphenylcyclotrisiloxane as the Main Product and Its Isolation

2014 ◽  
Vol 33 (22) ◽  
pp. 6278-6281 ◽  
Author(s):  
Fujio Yagihashi ◽  
Masayasu Igarashi ◽  
Yumiko Nakajima ◽  
Wataru Ando ◽  
Kazuhiko Sato ◽  
...  
Keyword(s):  
Main Product ◽  
Condensation Reaction ◽  
Unexpected Formation ◽  
Acid Catalyzed

Sulfamic Acid Catalyzed One-Pot Synthesis of Polyhydroquinolines via the Hantzsch Four Component Condensation Reaction

2009 ◽  
Vol 39 (3) ◽  
pp. 161-164 ◽  
Author(s):  
Naser Foroughifar ◽  
Akbar Mobinikhaledi ◽  
Mohammad Ali Bodaghi Fard ◽  
Hassan Moghanian ◽  
Sattar Ebrahimi
Keyword(s):  
Condensation Reaction ◽  
Sulfamic Acid ◽  
One Pot ◽  
One Pot Synthesis ◽  
Acid Catalyzed
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