54001-50-2Relevant articles and documents
Highly stereoselective, one-pot synthesis of azetidines and 2,4-dioxo-1,3-diazabicyclo[3.2.0] compounds mediated by I2
Miao, Chun-Bao,Dong, Chun-Ping,Zhang, Min,Ren, Wen-Long,Meng, Qi,Sun, Xiao-Qiang,Yang, Hai-Tao
, p. 4329 - 4340 (2013/06/05)
We report here a convenient method to construct polysubstituted azetidines and 2,4-dioxo-1,3-diazabicyclo[3.2.0] compounds with high stereoselectivities in a one-pot reaction mediated by I2. The tetramethylguanidine (TMG)/I2-mediated formal [2 + 2] cycloaddition reaction of α-amidomalonate 1 with enones 2 affords functionalized azetidine derivatives 4 in moderate to good yields with high diastereoselectivity. When the α-ureidomalonate 5 is used instead of 1, 2,4-dioxo-1,3-diazabicyclo[3. 2.0]heptanes 8 and 2,4-dioxo-1,3-diazabicyclo[3.2.0]heptenes 9 can be prepared selectively through the control of solvent and temperature. 2,4-Dioxo-1,3- diazabicyclo[3.2.0]heptanes 8 can further undergo ring-opening reactions with different nucleophilic reagents to afford the corresponding polyfunctionalized azetidine derivatives 13-16 with high steroselectivities.
The Chemistry of 5-Oxodihydroisoxazoles. Part 23. Photochemical and Thermal Reactions of Isoxazol-5(2H)-ones Substituted at C-3 or C-4 with Nitrogen, Oxygen or Sulfur
Khalafy, Jabbar,Prager, Rolf H.,Smith, Jason A.
, p. 518 - 536 (2007/10/03)
The photolysis of 2,3-dimethyl-4-phenoxy- and 4-thiophenoxyisoxazol-5(2H)-one in methanol has been re-examined, but no new products were isolated. Flash vacuum pyrolysis of the former gave a novel product, phenyl N-methylpropenimidate, from rearrangement of the intermediate carbene. Irradiation of the 3-hydroxy-2-phenyl-4-carboxylate gave two products which arise from the 3-hydroxy and 5-hydroxy tautomers. By contrast, the 3-hydroxy-4-acetyl isoxazolone reacted exclusively as one tautomer giving the expected loss of CO2 to form the carbene which was captured by methanol on photolysis, or underwent methyl migration and cyclisation to 3-methylazetidine-1,3-dione on pyrolysis. 3-Amino and 3-phenylamino substituted isoxazolones also gave photolysis and pyrolysis products characteristic of discrete tautomers.