109086-84-2Relevant academic research and scientific papers
Formation of 3,1-Perhydrobenzoxazines and their N-Methyl Derivatives. The Effects of Epimerization and Temperature
Parkkinen, Aija,Fueloep, Ferenc,Pihlaja, Kalevi
, p. 364 - 367 (2007/10/02)
The cyclization reactions of p-nitrobenzaldehyde with cis- and trans-2-hydroxy-methylcyclohexylamine and of their N-methyl derivatives have been studied by 1H NMR spectroscopy in CDCl3 solution.Time-dependent spectra confirmed that the reactions with both cyclohexylamines proceeded via open-chain intermediates whereas those with the N-methyl derivatives showed no signs of such intermediates.In all but one case the thermodynamically more stable 3,1-perhydrobenzoxazine epimer was also the kinetically favoured product.The effects of temperature and the presence of the minor epimer on the ring-chain tautomeric equilibria are also discussed.
Ring-Chain Tautomerism in 1,3-Oxazines
Fueloep, Ferenc,Pihlaja, Kalevi,Mattinen, Jorma,Bernath, Gabor
, p. 3821 - 3825 (2007/10/02)
A comparative study on the ring-chain tautomerism of 49 2-(substituted-phenyl) tetrahydro-1,3-oxazines of seven different types, namely, tetrahydro-1,3-oxazines 3,r-8a,c-2,c-4a- and r-8a,c-2,t-4a-1,3-perhydrobenzoxazines 5 and 7,r-8a,c-2,c-4- and r-8a,c-2,t-4a-1,3-perhydrobenzoxazines 9 and 11, 3,4-dihydro-2H-1,3-benzoxazines 12, and 1,2-dihydro-4H-3,1-benzoxazines 13, pointed out that in all cases the equilibria can be described with a simple equation, log Kx = (0.76 +/- 0.04)?+ + logKX=H where Kx = /(X/H).A factor c illustrating the sum of ster ic and electronic effects of substituents at C-4,C-5, and C-6 has also been introduced
