10.1021/om00152a031
The research aimed to explore the coordination chemistry of potentially tetradentate ligands with transition metals, focusing on the facile chelate-assisted carbon-halogen bond cleavage at tungsten(0). The study demonstrated that aryl carbon-halogen bonds of certain ligands, prepared by Schiff base condensation of ethylenediamine and 2-halobenzaldehyde (la-c, X = Cl, Br, I), could be readily cleaved by reaction with tungsten(0), resulting in the formation of seven-coordinate tungsten(II) complexes, W(CO)5(la-c). In contrast, the related ligand 1,4-bis(2-chlorobenzyl)2,3dimethyl-1,4diaza-2,3-butadiene (2) coordinated to tungsten(0) but did not oxidatively add under similar conditions. The research concluded that subtle changes in the ligand framework can significantly affect the propensity for oxidative addition in these systems. Key chemicals used in the process included tungsten carbonyls (W(CO)6 and W(CO)3(RCN)2), ethylenediamine, 2-halobenzaldehyde, and the ligand 2.
10.1021/jm00355a004
The research focuses on the development and evaluation of analogues of mitomycin C and porfiromycin with substituted ethylamines at position 7. These analogues were synthesized and tested for their antitumor activities against various mouse tumors, including P-388 leukemia, L-1210 leukemia, and B-16 melanoma. The study aimed to identify compounds that are at least as potent as mitomycin C but with reduced leukopenic effects. Key chemicals involved in the research include mitomycin C, porfiromycin, and a variety of ethylamine derivatives such as 2-phenylethylamine, 2-chloroethylamine, 2-hydroxyethylamine, and others with different functional groups at the 2-position of the ethylamine. The analogues were prepared using mitomycin A or N-methyl-mitomycin A as starting materials and various amines for substitution. The synthesized compounds were then purified, characterized, and tested for their biological activities. The results showed that some analogues exhibited better antitumor activity and reduced leukopenia compared to mitomycin C, with notable examples being the mercaptoethylamine analogue (8) and the fluoroethylamine analogue (4). The study also explored structure-activity relationships, finding a limited correlation between the potency of the analogues and their hydrophilicity.
10.1039/c0ob00644k
The study presents an efficient one-pot synthesis method for highly functional alkenes through a phosphine-catalyzed tandem three-component reaction involving aldehydes, alkyl vinyl ketones, and amides. The process utilizes either EtPPh2 or PPh3 as catalysts and achieves high yields (68–99%) with excellent stereoselectivity (E/Z ratios up to 98:2) within a total reaction time of 3 to 29.5 hours. The study also explores the scope of the reaction with various aryl- and heteroaryl-substituted aldehydes, amides, and alkyl vinyl ketones, demonstrating the versatility and practicality of the method. The reaction mechanism is proposed to involve a Morita–Baylis–Hillman reaction followed by a Michael addition, leading to the formation of the desired alkenes. The mild reaction conditions and the high atom economy of the process make it a valuable addition to organic synthesis.
10.1039/jr9640001727
The study investigates the reactions of aromatic nitro-compounds, specifically picramide (PicNH?) and its NN-dimethyl derivative (PicNMe?), in aqueous sodium hydroxide solutions. Picramide and dimethylpicramide both react with hydroxide ions to form soluble complexes. Picramide forms a 1:1 complex with hydroxide ions, while dimethylpicramide forms a 1:2 complex. The equilibrium constants for these reactions were measured. The study also examines the kinetics of the reactions, including the slow, irreversible hydrolysis that leads to the formation of picrate ions. In the presence of visible light, additional reactions occur, resulting in the formation of nitrite ions and a mixture of 3,5-dinitrocatechol and 2,6-dinitroquinone. The rates of these reactions were measured as a function of hydroxide ion concentration. The study aims to understand the behavior of these compounds in alkaline media and the nature of the complexes formed.
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