HENRY CONDENSATION UNDER HIGH PRESSURE. 2. EFFECT OF AROMATIC ALDEHYDE TYPE AND PRESSURE ON THE YIELD OF ω-NITROSTYRENES AND SECONDARY PROCESSES

Article abstract of DOI:10.1007/BF00965433

Condensation of aromatic aldehydes (I)-(XX) with EtNO2 and n-PrNO2 in AcOH in the presence of AcONH4 or i-BuNH2 gives primarily ω-nitrostyrenes (Ia, b) - (XXa, b) and small quantities of nitriles (Ic) - (XXc), oximes (Id) - (XXd), and ketones (Ie, f) - (XXe, f).The yields of (Ia, b) - (XXa, b) at P = 1 atm are higher for acceptor substitutents on the aromatic ring whereas at P = 10 kbar, they are higher for donor substituents.High pressures suppress the formation of (Ic-f) - (XXc-f) and the Z-isomers of (Ia, b) - (XXa, b).The high pressure technique is especially useful in the preparation of donor-substituted (Ia, b) - (XXa, b) which are intermediates in the synthesis of the psychotropic β-phenylethylamines.