10.3390/molecules25174009
The research focuses on the synthesis of potential haptens based on the morphine skeleton, aimed at developing a vaccination strategy against drug addiction and abuse. Haptens, which require a free amino or carboxylic group for coupling with an immunogenic carrier protein, were synthesized through reactions involving ethyl acrylate, ethyl bromoacetate, and N-(chloroacetyl)glycine ethyl ester. The study detailed the synthesis process, including N-demethylation and N-alkylation, and the subsequent hydrolysis to obtain N-carboxymethyl- and N-carboxyethyl-normorphine derivatives. The acid-base properties of these molecules were characterized using pH-potentiometry and NMR-pH titrations, with the protonation constants being determined to understand their pharmacokinetic behavior. The experiments utilized various reagents, solvents, and analytical techniques such as NMR, HR-MS, and potentiometric titrations to confirm the structures and physiochemical properties of the synthesized compounds.
10.1016/S0040-4020(02)01518-1
The study focuses on the synthesis of 3-substituted-4-hydroxyquinoline N-oxides from Baylis–Hillman adducts derived from o-nitrobenzaldehydes. The key chemicals used in the study include trifluoroacetic acid, trifllic acid, and various Baylis–Hillman adducts such as 1b–f, which are derived from methyl vinyl ketone, phenyl vinyl sulfone, and ethyl acrylate. These chemicals serve the purpose of facilitating the reaction that yields the desired quinoline N-oxide derivatives. The study also explores the reaction mechanism, suggesting that N-hydroxyisoxazoline acts as a key intermediate in the process. The use of triflic acid was found to increase the acidity of the reaction medium, which was crucial for obtaining the quinoline N-oxides in reasonable yields. The study provides experimental evidence supporting the proposed reaction mechanism and successfully synthesizes several 3-substituted-4-hydroxyquinoline N-oxides, which are valuable synthetic intermediates.
10.1055/s-1987-28108
The study presents a simple one-pot procedure for generating nitrilimines from N-acyl hydrazines using a halogenating-dehydrohalogenating system comprising triphenylphosphane, hexachloroethane, and triethylamine, via dichlorotriphenylphosphoranes. The in situ generated diphenylnitrilimine undergoes 1,3-dipolar cycloadditions with various dipolarophiles like ethyl acrylate and norbornene, yielding cycloadducts such as pyrazolines and pyrazoles. Additionally, 1,5-electrocyclizations of conjugated nitrilimines linked to heterocycles with suitable double bonds produce complex multicondensed heterocyclic systems. This method is advantageous due to the easy access to starting materials, straightforward reaction steps, and avoidance of contact with allergenic and skin-irritating hydrazonyl halides.
10.1021/jo00805a002
The study investigates the reactions of 2-diazoacenaphthenone (1) with various olefins and acetylenes. The researchers found that 1 did not decompose in boiling benzene or toluene but underwent copper-catalyzed thermolysis in boiling toluene to form biacenedione. In boiling xylene, 1 produced biacenedione and a trace amount of acenaphthenequinone ketazine. When 1 reacted with olefins like ethyl acrylate, acrylonitrile, ethyl a-bromoacrylate, and methyl vinyl ketone in refluxing benzene, it yielded spiro[acenaphthenone-2,1'-cyclopropanes] (3a-d, 4a-c, 7) with two stereoisomers for some reactions. Reactions with acrolein, phenylacetylene, and diethyl acetylenedicarboxylate led to the formation of 2'-hydroxymethylspiro[acenaphthenone-2,1'-cyclopropanes] (5, 6) and spiro[acenaphthenone-2,3'(3'H)-pyrazoles] (9, 10). The study also explored the reaction of 1 with bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, producing spiro[acenaphthenone-2,3'-tricyclooctanedicarboxylic anhydride] (8). The researchers used various analytical techniques to confirm the structures and properties of the synthesized compounds.
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