Unexpected Reaction Products of Uracil and Its Methyl Derivatives with Acetic Anhydride and Methylene Chloride

2021 ◽  
Author(s):  
Olga Michalak ◽  
Piotr Cmoch ◽  
Andrzej Leś ◽  
Marcin Cybulski ◽  
Piotr Krzeczyński ◽  
...  
Keyword(s):  
Acetic Anhydride ◽  
Methylene Chloride ◽  
Reaction Products ◽  
Unexpected Reaction ◽  
Methyl Derivatives

Reactivity of silica-supported zirconium neopentyl fragments with trimethylphosphine and acetone: Formation of unexpected reaction products

2007 ◽  
Vol 692 (19) ◽  
pp. 4193-4195 ◽  
Author(s):  
Virginie Riollet ◽  
Mostafa Taoufik ◽  
Jean-Marie Basset ◽  
Frédéric Lefebvre
Keyword(s):  
Reaction Products ◽  
Unexpected Reaction

Reactions of phenyl-substituted heterocyclic compounds. VII. Reagent-dependent orientation in the nitration of 4-phenylpyrimidine

1967 ◽  
Vol 45 (13) ◽  
pp. 1431-1437 ◽  
Author(s):  
Brian M. Lynch ◽  
Lizzie Poon
Keyword(s):  
Nitric Acid ◽  
Acetic Anhydride ◽  
Nucleophilic Addition ◽  
Heterocyclic Compounds ◽  
Trifluoroacetic Anhydride ◽  
Reaction Products ◽  
Heterocyclic Nitrogen

In the nitration of 4-phenylpyrimidine, the nature of the reaction products is strongly dependent upon the nitrating reagent. Mixed nitric and sulfuric acids yield 4-o- and 4-m-nitrophenylpyrimidines in the ratio 2:3, whereas nitric acid – trifluoroacetic anhydride yields 4-o-, 4-m-, and 4-p-nitrophenylpyrimidines in the ratio 45:29:26, and nitric acid – acetic anhydride yields 2,4-diacetoxy-1,3,5-trinitro-6-phenyl-1,2,3,4-tetrahydropyrimidine.An explanation of these findings involves the possibility of the addition of nitronium ion at the heterocyclic nitrogen, followed in some circumstances by nucleophilic addition.

Adduct Intermediates in the Side-chain Nitration of 1,4-Dimethylnaphthalene

1972 ◽  
Vol 50 (24) ◽  
pp. 3988-3992 ◽  
Author(s):  
Alfred Fischer ◽  
Alan Leslie Wilkinson
Keyword(s):  
Acetic Acid ◽  
Nitric Acid ◽  
Acetic Anhydride ◽  
Room Temperature ◽  
Methylene Chloride ◽  
Side Chain ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Cis And Trans ◽  
Naphthyl Acetate

cis and trans isomers of 1,4-dimethyl-4-nitro-1,4-dihydro-1-naphthyl acetate (1) have been isolated from a mixture of 1,4-dimethylnaphthalene and nitric acid in acetic anhydride by quenching at −40°. At room temperature only 1-methyl-4-nitromethylnaphthalene (4) is obtained. The conversion of 1,4-dimethylnaphthalene to 4 and of the cis (1a) and trans (1b) adducts to 4, by nitric acid in acetic anhydride, has been followed by n.m.r. 1,4-Dimethyl-4-nitro-1,4-dihydro-1-naphthyl nitrate (5) appears to be the immediate product from nitration of 1,4-dimethylnaphthalene in acetic anhydride, methylene chloride, or nitromethane. In acetic anhydride 5 is converted into 1. Decomposition of 1 in acetic acid gives 1,4-dimethyl-2-naphthyl acetate and some 4. The formation of 4 in this reaction is suppressed by urea.

Piptoside, a novel alkali-labile glucoside from Piptocalyx moorei Oliv.

1966 ◽  
Vol 19 (4) ◽  
pp. 683 ◽  
Author(s):  
NV Riggs ◽  
JD Stevens
Keyword(s):  
Periodate Oxidation ◽  
Aqueous Sodium Hydroxide ◽  
Carbon Chain ◽  
Hydroxyl Group ◽  
Reaction Products ◽  
Spectroscopic Information ◽  
Michael Type Addition ◽  
Angelic Acid ◽  
Methyl Derivatives ◽  
Fission Yields

The β-D-glucopyranoside, piptoside, is cleaved by hot dilute acid to glucose and aglucone, the latter being partly converted with loss of carbon dioxide into a furan keto acid. Glucose is also liberated by the action of bases. With sodium methoxide, the aglucone residue rearranges to a pair of isomeric dilactone esters, whereas, with aqueous sodium hydroxide, fission of the carbon chain to (-)-2,3-dimethylsuccinic acid occurs; with alkaline hydrogen peroxide, oxidative chain fission yields a buty- rolactone-4,4-dicarboxylic acid. The structure and partial stereochemistry of each of the products follows from chemical and spectroscopic information. These results, as also those of periodate oxidation, are accounted for by formulation of the aglucone as a system of two spiro-joined γ-lactone rings, one of which is fused to a ketofuranose ring. The reaction products are analogous to well-known products from simple sugars. The hemiacetal hydroxyl group of the ketofuranose remains free in the glucoside and is unusally acidic towards diazomethane, the methyl derivatives not being alkalilabile.��� Biogenesis of the aglucone may follow Michael-type addition of a 3-dehydrohexonic acid (of unknown stereochemistry) to angelic acid, or some variant.

Protein-templated gold nanoparticle synthesis: protein organization, controlled gold sequestration, and unexpected reaction products

2017 ◽  
Vol 46 (47) ◽  
pp. 16465-16473 ◽  
Author(s):  
Cassidy Hart ◽  
Nouf Abuladel ◽  
Madeleine Bee ◽  
Megan C. Kreider ◽  
Alexander C. CVitan ◽  
...  
Keyword(s):  
Gold Nanoparticle ◽  
Nanoparticle Synthesis ◽  
Reaction Products ◽  
P Protein ◽  
Low Concentrations ◽  
Unexpected Reaction ◽  
Gold Nanoparticle Synthesis ◽  
Novel Products

Protein-based nanoparticle templating reactions show faster kinetics and novel products at low concentrations.

Radical rearrangement and transfer reactions in proteins

2020 ◽  
Vol 64 (1) ◽  
pp. 87-96
Author(s):  
Christian Schöneich
Keyword(s):  
Organic Chemistry ◽  
Protein Sequence ◽  
Transfer Reactions ◽  
Reaction Products ◽  
Chemical Modifications ◽  
Structure And Dynamics ◽  
Radical Rearrangement ◽  
Unexpected Reaction

Abstract Radical rearrangement and transfer reactions play an important role in the chemical modifications of proteins in vivo and in vitro. These reactions depend on protein sequence, as well as structure and dynamics. Frequently, these reactions have well-defined precedents in the organic chemistry literature, but their occurrence in proteins provides a stage for a number of novel and, perhaps, unexpected reaction products. This essay will provide an overview over a few representative examples of radical rearrangement and transfer reactions.

scholarly journals Preparation and activity of guanidinated or acetylated erabutoxins

1976 ◽  
Vol 153 (2) ◽  
pp. 217-222 ◽  
Author(s):  
H Hori ◽  
N Tamiya
Keyword(s):  
Circular Dichroism ◽  
Acetic Anhydride ◽  
Column Chromatography ◽  
Reaction Products ◽  
Amino Groups ◽  
Sea Snake ◽  
Lysine Residues ◽  
Erabutoxin B ◽  
Circular Dichroïsm

1. Erabutoxins, a, b and c, neurotoxic proteins of a sea snake Lacticauda semifasciata, were guanidinated with O-methylisourea. The amino groups of all the lysine residues and those at the N-termini of the toxins were modified. The lethal activity of the toxins decreased to 50% (erabutoxins a and b) or 17% (erabutoxin c) of the original value on the modification. The c.d. (circular dichroism) maximum at 227 nm of the modified toxins became lower, whereas the whole profile of the c.d. curve remained unchanged. 2. The amino groups of erabutoxin b were acetylated with acetic anhydride. All the five monoacetyl derivatives were isolated from the reaction products by CM-cellulose and Bio-Rex 70 column chromatography. [1-Nalpha-acetylarginine]-, [15-N6-acetyl-lysine]- and [51-N6-acetyl-lysine]-erabutoxin b retained the toxicity of the native toxin, whereas [27-N6-acetyl-lysine] and [47-N6-acetyl-lysine]-erabutoxin b were 17 and 8% active respectively. The overall profile of c.d. spectrum of erabutoxin b remained unchanged on the monoacetylation.

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