The reaction under mild conditions between formaldehyde and phenylalanine and phenylethylamine derivatives has been studied. When the amines included in a dried protein film were exposed to formaldehyde vapour a very intense green to yellow fluorescence was give only by those that as well as being primary amines also have hydroxyl groups at the 3 and 4 positions (3,4-dihydroxyphenylalanine, dopamine, noradrenaline). The 3-OH group seems to be esssential for the reaction. The catechol amines, which are secondary amines (adrenaline, epinine), gave a much weaker fluorescence that developed more slowly.The results obtained on further examination of the reaction favour the view that the amines primarily condense with formaldehyde to 1,2,3,4-tetrahydroisoquinolines which are involved in a secondary reaction to become highly fluorescent and at the same time insoluble. This secondary reaction may be a binding to protein, and oxidation with the formation of double bonds in the heterocyclic ring, or both.

Fluorescence of Catechol Amines and Related Compounds Condensed With Formaldehyde

4.2.8. Reductive Coupling 3109 5. Reaction of Aromatic Compounds 3110 5.1. Electrophilic Substitutions 3110 5.2. Radical Substitution 3111 5.3. Oxidative Coupling 3111 5.4. Photochemical Reactions 3111 6. Reaction of Carbonyl Compounds 3111 6.1. Nucleophilic Additions 3111 6.1.1. Allylation 3111 6.1.2. Propargylation 3120 6.1.3. Benzylation 3121 6.1.4. Arylation/Vinylation 3121 6.1.5. Alkynylation 3121 6.1.6. Alkylation 3121 6.1.7. Reformatsky-Type Reaction 3122 6.1.8. Direct Aldol Reaction 3122 6.1.9. Mukaiyama Aldol Reaction 3124 6.1.10. Hydrogen Cyanide Addition 3125 6.2. Pinacol Coupling 3126 6.3. Wittig Reactions 3126 7. Reaction of R,â-Unsaturated Carbonyl Compounds 3127

Organic Reactions in Aqueous Media with a Focus on Carbon−Carbon Bond Formations: A Decade Update

The histochemical fluorescence method of Falck and Hillarp for the demonstration of biogenic monoamines is based on the finding that the amines can be condensed with formaldehyde to yield strongly fluorescent compounds, provided that they are enclosed in a dried protein layer, as in freeze-dried or air-dried tissues. This review deals mainly with certain principal features of the method: its chemistry, sensitivity, specificity and possibilities for histochemical differentiation between the various amines. Some comments are made on certain of the results obtained with this method.

The formaldehyde fluorescence method for the histochemical demonstration of biogenic monoamines a review on the methodology

https://faculty.missouri.edu/~glaserr/3700s14/Antioxidant_Vitamins_C_and_E.pdf

Vitamins C and E: beneficial effects from a mechanistic perspective.

Acrolein (2-propenal) is ubiquitously present in (cooked) foods and in the environment. It is formed from carbohydrates, vegetable oils and animal fats, amino acids during heating of foods, and by combustion of petroleum fuels and biodiesel. Chemical reactions responsible for release of acrolein include heat-induced dehydration of glycerol, retro-aldol cleavage of dehydrated carbohydrates, lipid peroxidation of polyunsaturated fatty acids, and Strecker degradation of methionine and threonine. Smoking of tobacco products equals or exceeds the total human exposure to acrolein from all other sources. The main endogenous sources of acrolein are myeloperoxidase-mediated degradation of threonine and amine oxidase-mediated degradation of spermine and spermidine, which may constitute a significant source of acrolein in situations of oxidative stress and inflammation. Acrolein is metabolized by conjugation with glutathione and excreted in the urine as mercapturic acid metabolites. Acrolein forms Michael adducts with ascorbic acid in vitro, but the biological relevance of this reaction is not clear. The biological effects of acrolein are a consequence of its reactivity towards biological nucleophiles such as guanine in DNA and cysteine, lysine, histidine, and arginine residues in critical regions of nuclear factors, proteases, and other proteins. Acrolein adduction disrupts the function of these biomacromolecules which may result in mutations, altered gene transcription, and modulation of apoptosis.

/pdf/acrolein-sources-metabolism-and-biomolecular-interactions-4owvvlnfgc.pdf

Acrolein: sources, metabolism, and biomolecular interactions relevant to human health and disease.

Correlation of the von Braun, Ritter, Bischler-Napieralski, Beckmann and Schmidt reactions via nitrilium salt intermediates

A new role for l-ascorbic acid: michael donor to α,β-unsaturated carbonyl compounds

Use of acyl migration in separating diastereoisomeric amino alcohols

The mechanism of the bischler‐napieralski reaction

The configurations of ring nitrogen in the amine oxides of tropine, oscine, atropine, and scopolamine have been investigated by nuclear magnetic resonance (n.m.r.) spectroscopy. Oxygen function(s) at C-6β (and 7β) were found to deshield the low-field, equatorial N-methyl signal. Analysis of the n.m.r. spectra of epoxides of some tropane bases, in particular the coupling constants, clearly indicates preponderance of the (slightly distorted) chair conformation even in the tropanes with a bulky group in the 3α (endo) position. The protons on the epoxide carbons are magnetically non-equivalent in scopolamine (5b) and its N-oxide while appearing as a singlet in the alkamine, i.e. scopine (5a).

Gabor Fodor

Papers

Correlation of the von Braun, Ritter, Bischler-Napieralski, Beckmann and Schmidt reactions via nitrilium salt intermediates

A new role for l-ascorbic acid: michael donor to α,β-unsaturated carbonyl compounds

Use of acyl migration in separating diastereoisomeric amino alcohols

The mechanism of the bischler‐napieralski reaction

Configuration of the ring nitrogen in N-oxides and the conformation of tropanes. Part XVIII