97958-29-7Relevant academic research and scientific papers
PYRIDINE ASSISTED OXIDATIONS OF ALCOHOLS TO CARBONYL COMPOUNDS BY MEANS OF 3-CARBOXYPYRIDINIUM DICHROMATE (NDC) REAGENT.
Cossio, Fernando P.,Lopez, Concepcion M.,Palomo, Claudio
, p. 3963 - 3974 (2007/10/02)
3-carboxypyridinium dichromate (NDC), readly prepareted from nicotinic acid and chromium trioxide, is an efficient reagent for the oxidation of alcohols into carbonyl compounds in the presence of pyridine.The optimum molar ratio substrate:reagent:pyridine to ensure complete oxidation of starting material in a short reaction time was found 1:2.5:20 respectlively.A brief compouison between this reagent and pyridinium dichromate (PDC) is made.In contrast to the PDC reagent, NDC allows selective oxidation between benzylic alcohols and aliphatic alcohols.The NDC-pyridine system has been successfully extended to the oxidation of N-(2-hidroxy-2-phenyl or 2-methylethyl)-β-lactams into their corresponding carbonyl compounds as N-H azetidin-2-one precursor.In contrast, primary N-(2-hydroxyethyl)-β-lactams upon treatment with this reagent system afforded N-formylazetidin-2-ones.The influence of pyridine in oxidations by means of NDC is further shown in the conversion of hydroquinones into quinones.Another interesting feature associated with the use of this reagent is the ease of purification of the final products.
Synthesis of β-lactams from acetic acids and imines induced by phenyl dichlorophosphate reagent
Arrieta,Cossio,Palomo
, p. 1703 - 1712 (2007/10/02)
The development of a practical method for the preparation of vinylamino-β-lactams from Dane salts and Schiff bases is described. Among the reagents known to produce β-lactams from imines and acetic acids, only phenyl dichlorophosphate and 1-methyl-2-chloropyridinium iodide are suitable for the synthesis of vinylamino-β-lactams. Reaction of acetic acids with ethanolimine derivatives promoted by phenyl dichlorophosphate affords oxazolidines instead of β-lactams. Protection of the hydroxyl group as the trimethylsilyl ether in the starting Schiff bases provides a convenient route to the corresponding β-lactams instead of oxazolidines. Some observations on the scope of the method are made.
A NOVEL SYNTHETIC APPROACH TO N-UNSUBSTITUTED β-LACTAMS
Cossio, Fernando P.,Palomo, Claudio
, p. 4235 - 4238 (2007/10/02)
A convenient simple route to N-unsubstituted β-lactams is described.Formation of unusual N-styryl-β-lactams is the key of the method.
