75907-23-2Relevant academic research and scientific papers
Simple access to highly functional bicyclic γ- and δ-lactams: Origins of chirality transfer to contiguous tertiary/quaternary stereocenters assessed by DFT
Le Goff, Ronan,Martel, Arnaud,Sanselme, Morgane,Lawson, Ata Martin,Dach, Adam,Comesse, Sbastien
supporting information, p. 2966 - 2979 (2015/02/19)
This paper describes the synthesis of both polysubstituted oxazolo-pyrrolidinones and -piperidinones by a domino process. The methodology is based on the reaction between hydroxyl halogenoamides and Michael acceptors, which leads efficiently to bicyclic lactams. The process is compatible with unsymmetrical electron-withdrawing groups on the Michael acceptor, which allows the formation of two contiguous and fully controlled tertiary and quaternary stereocenters. In the case of tetrasubstituted Michael acceptors, two adjacent quaternary stereocenters are formed in good yield. Starting from (R)-phenylglycinol derived amides results in the formation of enantioenriched bicyclic lactams in low to good yields and with high levels of stereo-selectivity, thus greatly increasing the scope and interest of this strategy. The origins of chirality transfer and diastereoselectivity were studied by DFT calculations and have been attributed to a kinetic control in one of the last two steps of the reaction sequence. This selectivity is dependent upon both the substituents on the Michael acceptor and the sodium cation chelation.
Synthesis of 3-substituted and 3,4-disubstituted pyrazolin-5-ones
Jung, Jae-Chul,Watkins, E.Blake,Avery, Mitchell A
, p. 3639 - 3646 (2007/10/03)
The synthesis of 3-substituted and 3,4-disubstituted pyrazolin-5-ones from acylated ethyl acetoacetates and diethyl malonates is described. The reaction of acylated ethyl acetoacetates and diethyl acetylmalonate with hydrazine (98%) gave 3-substituted pyrazolin-5-ones and malonyldihydrazide, respectively, following a deacetylation-condensation sequence. The reaction of ethyl 2-acetyl-3-hydroxy-2-butenoate and diethyl 2-(1-hydroxyethylidene)malonate with hydrazine monohydrochloride yielded ethyl 3,5-dimethyl-1H-pyrazole-4-carboxylate and 4-ethoxycarbonyl-3-methylpyrazolin-5-one, respectively, following a dehydration-cyclocondensation sequence, in high yields.
TRANSMISSION OF SUBSTITUENT EFFECTS IN PARA SUBSTITUTED BENZOYLMALONATE DERIVATIVES
Bankowska, Zofia,Zadrozna, Irmina,Bochenska, Joanna
, p. 461 - 467 (2007/10/02)
Acidity constants and enol contents of ethyl benzoylmalonate and its para derivatives (CH3O, CH3, Cl, CN, NO2) were determined in 75 vol.percent ethanol-water solutions.Acidity constants of keto and enol forms were calculated and correlated with substituents constants ?p.IR spectra and enol contents were also determined in CCl4 solutions.
