144731-09-9Relevant articles and documents
1H NMR spectroscopic studies of the stability of an oxazolidine condensation product
Moloney, Gerard P.,Iskander, Magdy N.,Craik, David J.
, p. 337 - 341 (1997)
Condensation of (-)-norephedrine with excess formaldehyde under mild conditions leads to formation of the 2:1 condensation product N,N'-methylenebis(4-methyl-5-phenyl)oxazolidine compared with the reaction with 1 mol of formaldehyde, which leads to 4-methyl-5-phenyloxazolidine. 1H and 13C NMR spectroscopy was used to monitor the stability of this compound and its decomposition products. The 2:1 condensation product is found to be stable in CDC13 but breaks down rapidly in CD3OD to yield a 50:50 mixture of 4-methyl-5-phenyloxazolidine and 3-hydroxymethyl-4-methyl-5-phenyloxazolidine. Upon addition of D2O to this equimolar mixture, the latter compound decomposes to norephedrine and formaldehyde, whereas the former compound is stable.
Equilibrium between bis(1,3-oxazolidin-3-YL])methanes and 3,8-dioxa1,6-diazabicyclo[4.4.1]Undecanes
Salas-Coronado, Raul,Galvez-Ruiz, Juan Carlos,Guadarrama-Perez, Carlos,Flores-Parra, Angelina
, p. 1123 - 1132 (2007/10/03)
The equilibrium between bis(1,3-oxazolidin-3-yl])methanes (A) and 3,8-dioxa-1,6-diazabicyclo[4.4.1]undecanes (B) is reported. A and B were prepared from formaldehyde and (±)-1-methylethanolamine (1), 2,2-dimethylethanolamine (2), (1S, 2R)-1-methyl-2-phenylethanolamine (3), ethanolamine (4), (R)-2-carboxyethanolamine methyl ester (5), (S)-2-ethylethanolamine (6), (R)-2phenylethanolamine (7). The equilibrium depends on the substituents. Thermodynamic structures (A) derived from 5 and 7 by slow crystallization are completely transformed into undecanes (B) by an equilibrium asymmetric transformation. Structures were established by 1H, COSY, HETCOR and NOESY NMR experiments. Preferred conformer of the undecane ring was identified.
