70766-02-8Relevant academic research and scientific papers
Scandium(III) Triflate Catalyzed Direct Synthesis of N-Unprotected Ketimines
Hirazawa, Yoshinobu,Kadota, Tetsuya,Kondo, Yuta,Morimoto, Hiroyuki,Morisaki, Kazuhiro,Ohshima, Takashi
, p. 120 - 125 (2020/02/20)
N-Unprotected ketimines are useful substrates and intermediates for synthesizing valuable nitrogen-containing compounds, but their potential applicability is limited by the available synthetic methods. To address this issue, we report a scandium(III) triflate catalyzed direct synthesis of N-unprotected ketimines. Using commercially available reagents and Lewis acid catalysts, ketones were directly transformed into the corresponding N-unprotected ketimines in high yields with broad functional group tolerance, even in multigram scales. The reactions were readily applicable for one-pot synthesis of important compounds such as a glycine Schiff base without isolation of N-unprotected ketimine intermediates. Preliminary mechanistic studies to clarify the reaction mechanism are also described.
A TRANSAMINATIVE SYNTHESIS OF 9-AMINO-9-FLUORENECARBOXYLIC ACID ESTERS
DuPriest, Mark T.,Conrow, Raymond E.,Kuzmich, Daniel
, p. 2959 - 2962 (2007/10/02)
The benzyl imines of several fluorenones were treated with base, followed by methyl chloroformate, to introduce the carbomethoxy group at the 9-fluorenyl position.Imine hydrolysis afforded the title compounds.The reaction was readily conducted on a 30-g s
X=Y-ZH SYSTEMS AS POTENTIAL 1,3-DIPOLES. PART 21 ACTIVATION OF THE ZH PROTON IN IMINES.
Grigg, Ronald,Donegan, Gregory,Gunaratne, H. Q. Nimal,Kennedy, Deirdre A.,Malone, John F.,et al.
, p. 1723 - 1746 (2007/10/02)
Imines, RCH=N-ZH, possessing a range of ZH groups (Z=CHCOPh, CHCOSR, CHCONHR, CHP(O)(OEt)2, 2-CH-pyridyl, 2-CH-thiazolyl, and 9-fluorenyl) undergo thermal 1,2-prototropy generating azomethine ylides stereospecifically.The intermediate azomethine ylides un
Acidities of Glycine Schiff Bases and Alkylation of Their Conjugate Bases
O'Donnell, Martin J.,Bennett, William D.,Bruder, Willian A.,Jacobsen, William N.,Knuth, Keith,et al.
, p. 8520 - 8525 (2007/10/02)
Equilibrium acidities in Me2SO are reported for six ketimines of the type Ph2C=NCH(R)CO2Et and five aldimines, ArCH=NCH(R)CO2Et.Changing R in the ketimine from H to Ph increased the pKa by 2.2 units.This surprising acidity decrease for Ph substitution points to a substantial increase in steric effect, as do the increases in pKa of 3.8 and 4.2 units observed for the replacement of hydrogen by Me and PhCH2, respectively.Phase-transfer alkylation of the Ph2C=NCH2CO2Et ketimine gave over 90 percent of monoalkylate whereas, under similar conditions, the aldimine 4-ClC6H4CH=NCH2CO2Et gave a mixture of mono- and dialkylate.The difference is that the pKa of the monoalkylated aldimine is essentially the same as that of the parent, which leads to rapid equilibration with the parent anion and consequent dialkylation.The rates of alkylation in Me2SO of these parent and monoalkylated anions did not differ greatly, showing that the relative pKHAs of the parent acid and its monoalkyl derivative, rather tham the relative rates of the mono- and dialkylation reactions, is the principal factor that determines the extent of the competition between monoalkylation and dialkylation.
The Synthesis of NH Aldimines and Derivatives by Spontaneous and Base-catalysed Decomposition of Oxaziridines
Boyd, Derek R.,Coulter, Peter B.,Hamilton, Robert,Thompson, Norris T.,Sharma, Narain D.,Stubbs, Michael E.
, p. 2123 - 2128 (2007/10/02)
A range of oxaziridines containing N-methylene substituents has been synthesized by peracid oxidation of the corresponding fluorenylidene N-alkylamines.Spontaneous and tertiary amine base-catalysed decomposition of the oxaziridines into unstable NH aldimines and derivatives was observed.Acrylaldehyde, 2-methylacrylaldehyde, and benzaldehyde NH imines have been identified as initial products from decomposition of the corresponding oxaziridines. 2,4,6-Trialkylhexahydro-1,3,5-triazines, N,N'-dialkylidene-1,1-diaminoalkanes, N,N'-diarylidene-1,1-diaminoalkanes, and N-isobutylidene-2-methylpropenylamine were among the isolated products formed via the undetected alkyl aldehyde NH imines resulting from oxaziridine decomposition.
Activated C,H-Acids: N-Alkyl-9-fluorenimines
Bradamante, Silvia,Colombo, Silvana,Pagani, Giorgio A.,Roelens, Stefano
, p. 2524 - 2527 (2007/10/02)
N-Substituted 9-fluoremines 1 are easily prepared from primary amines or aminoesters and 9-fluorenimine: their conjugate carbanions 2 are formed by the action of alkoxides and are reprotonated to 1 or to the tautomeric 9-alkylidenaminofluorenes 3 dependin
