| abstract |
They respond to the formula: where R₁ and R₂ identical represent -CH₂R where R = H or C₁-C₄ alkyl, or R₁ and R₂ together form a group -CH₂ (CR₄R₄) n where n = 0 or 1, R₄ = H or -CH₃, R₃ = H or -CH₂R₅ where R₅ = H or C₁-C₄ alkyl, either A and A₁ identical represent H, or A and A₁ together seem to be an ethylene, trimethylene radical, -CH (OCH₂R₆) - where R₆ = H or an alkyl in C₁-C₄ or, when R₃ = H, a dihydroxy-1,2-ethylene group.n n n Their process of obtaining consists in reacting a disubstituted ethanal with an ANH-CO-NHA₁ urea, reaction possibly followed by etherification with an alcohol R₅CH₂OH. |