2539-17-5Relevant academic research and scientific papers
Crown Ethers from o-Quinone Diazides and Oxetane
Kirmse, Wolfgang,Lelgemann, Rudolf
, p. 1865 - 1866 (2007/10/02)
The carbenes 11, generated by photolysis of the di- and tetrachloro-o-quinone diazides 10, react with oxetane in a 1:3 ratio to give the 15-membered crown ethers 19.In the presence of methanol, the oxonium ions 12 are trapped with formation of 1-(aryloxy)-3-methoxypropanes (13).In the absence of additional nucleophiles, 12 react with oxetane until the chain length is appropriate for inverting intramolecular attack of the aryl oxide at the α-carbon atom of the oxonium ion (18 -> 19). Key Words: Carbonyl carbenes/ Oxygen ylides/ Displacement, nucleophilic, intramolecular/ Carbenes/ Ylides
FORMATION OF A TRIMERIC CHLOROGUAIACOL QUINONE IN THE PREPARATION OF TETRACHLOROGUAIACOL AND CRYSTAL STRUCTURE OF ITS TETRAMETHOXY DERIVATIVE
Burlinson, Nick,Rettig, Steven J.,Trotter, James,McKague, Bruce
, p. 950 - 954 (2007/10/02)
A by-product formed in the preparation of tetrachloroguaiacol is shown to be a trimeric quinone.Derivatization of the quinone to a crystalline tetramethoxy derivative allowed X-ray determination of its crystal structure as 3,6-dichloro-4,5-dimethoxy-1,2-bis(2'-methoxy-3',4',5',6'-tetrachlorophenoxy)benzene, 4.Rarely observed long range JCH coupling between ring carbons and methoxyl hydrogens as well as conformational isomerism were observed in 1H and 13C nmr studies of 4.Crystals of 4 are triclinic, a = 12.562(1), b = 12.708(1), c = 9.223(1) Angstroem, α = 96.93(1), β = 97.478(7), γ = 101.285(8) deg, Z = 2, space group .The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.056 and Rw = 0.056 for 2946 reflections with I >/= 1.5?(I).The molecule contains a central six-membered dichloro-tetraoxo substituted aromatic ring, linked via oxygen bridges to two identical tetrachloro-dioxo substituted rings; intramolecular steric overcrowding causes significant deviations from a symmetrical conformation.Bond lengths, angles, and intermolecular distances are generally close to expected values.
