56501-37-2Relevant academic research and scientific papers
Convenient synthesis of 2-Amino-4H-chromenes from photochemically generated o-quinone methides and malononitrile
Fujiwara, Makoto,Sakamoto, Masanori,Komeyama, Kimihiro,Yoshida, Hiroto,Takaki, Ken
, p. 59 - 66 (2015/01/30)
2-Amino-4H-chromenes were synthesized in moderate to good yields by the reaction of o-quinone methides photochemically generated from o-(dimethylaminomethyl)phenols with malononitrile. This method was applicable to the synthesis of fluorinated chromenes that were difficult to obtain by other methods. In addition, o-(hydroxymethyl)phenols could be used for the reaction in the presence of tertiary amine bases.
Ring Expansion and Contraction of a Two-Carbon Bridged Spiropentane
Wiberg, Kenneth B.,Snoonian, John R.
, p. 1390 - 1401 (2007/10/03)
The reactions of tricyclo[4.1.0.01,3]heptan-4-one (5) and two related systems with diazomethane and m-CPBA were examined in order to determine the relative reactivity and migratory aptitudes for the three compounds. The reactions of 5 with diazomethane and m-CPBA yielded new derivatives of the tricyclo[5.1.0.01,3]octane ring system that showed that migration of cyclopropylcarbinyl is favored over cyclopropyl migration in this system. Photolysis of 5-diazotricyclo[4.1.0.01,3]heptan-4-one (23) in methanol and dimethylamine did not lead to ring contraction to the tricyclo[3.1.0.01,3]hexane ring system, but an interesting product was derived from an unusual rearrangement process in the photolysis in dimethylamine. Matrix photolysis of 23 at 15 K gave a decrease in the diazo band at 2085 cm-1 and the appearance of a new band at 2117 cm-1, which is a normal position expected for a small-ring ketene such as cyclopropylketene. Thus, matrix photolysis appears to have yielded a derivative of the previously unknown tricyclo[3.1.0.01,3]hexane ring system. The lithium enolate of 5 was characterized by NMR spectroscopy at -80 °C and was found to rearrange to m-cresol at -65 °C. The geometries of the bridged spiropentanes of this work were optimized at the MP2(frozen core)/6-31G* level of theory, and group equivalent values were derived in order to calculate the heats of formation for these compounds using the calculated energies.
