10.1021/ol0521432
The research focuses on the selective diphosphorylation, dithiodiphosphorylation, triphosphorylation, and trithiotriphosphorylation of unprotected carbohydrates and nucleosides using solid-phase synthesis. The purpose of this study was to develop a method for the selective synthesis of these compounds, which are challenging to produce due to the lack of regioselectivity in traditional solution-phase methods. The researchers used aminomethyl polystyrene resin-bound linkers of p-acetoxybenzyl alcohol, which were subjected to reactions with diphosphitylating and triphosphitylating reagents to yield polymer-bound reagents. These were then reacted with unprotected carbohydrates and nucleosides to produce monosubstituted nucleoside and carbohydrate diphosphates, dithiodiphosphates, triphosphates, and trithiotriphosphates with high regioselectivity. The conclusions of the research highlight the advantages of the solid-phase approach, including the production of monosubstituted derivatives, high selectivity, facile isolation and purification of products, and the trapping of byproducts on resins. The chemicals used in the process included phosphorus trichloride, 3-hydroxypropionitrile, diisopropylamine, water, and 1H-tetrazole, among others, to synthesize the diphosphitylating and triphosphitylating reagents, as well as various unprotected nucleosides and carbohydrates for the reactions.
10.1016/S0040-4020(01)92361-0
The research focuses on the amidinoethylation of amino compounds, a new reaction that involves the addition of amines to the C=C double bond of various N,N'-substituted-propenamidines. The purpose of this study was to explore the synthesis of 3-amino-substituted-N,N'-substituted-propanamidines, which are not easily accessible through classical synthetic methods. The researchers found that the most nucleophilic amines, such as piperidine, morpholine, and pyrrolidine, added under mild conditions, while aliphatic and aromatic amines required more drastic conditions. The conclusions drawn from the study illustrate the activation of the C=C double bond of propenamidines by the conjugated amidine function, providing a new class of Michael acceptors for amino compounds. The chemicals used in the process include a variety of amines, such as piperidine, morpholine, pyrrolidine, cyclohexylamine, diisopropylamine, and aromatic amines, as well as solvents like acetonitrile, dimethylformamide, and ethylene glycol dimethylether, and catalysts such as acetic acid and SnCl4.
10.1055/s-1985-31216
The research aims to improve the yield and purity of isocyanide synthesis using phosphoryl chloride and disopropylamine. Traditionally, isocyanides are synthesized by dehydrating formamides, often using reagents like phosgene or diphosgene, which are highly toxic and costly. This study explores an alternative method using phosphoryl chloride combined with disopropylamine as a base. The researchers found that replacing the commonly used triethylamine with disopropylamine significantly enhances the yield and purity of isocyanides, often eliminating the need for chromatographic purification. The method is particularly effective for synthesizing ferrocenylalkyl isocyanides, where other methods fail or produce impurities. The study concludes that this new method is milder, more reproducible, and yields higher purity isocyanides compared to traditional methods, making it a valuable improvement in the field of isocyanide synthesis.
F,
C
F:Flammable;
