Syntheses in the field of 5-nitro-2-furylpolyalkenals and 5-nitro-2-furylpolyalkenones

A series of, -bis(5-nitro-2-furyl)poryalkenones has been synthesized by the condensation of 5-nitro-2-furylalkenones with 5-nitrofuran aldehydes in acetic acid (concentrated sulfuric acid catalyst). In the , -bis(5-nitro-2-furyl)polyalkenone series, the keto group acts as a partial insulator of conjugation, which is shown most clearly in the case of 1,3-bis(5-nitro-2-furyl)prop-2-en-1-one and 1,5-bis(5-nitro-2-furyl)-penta-2,4-dien-1-one, i.e. compounds having the keto group directly linked to a 5-nitrofuran ring. The electronic spectra of the semicarbazones of the, -bis(5-nitro-2-furyl)polyalkenones exhibit a stronger disturbing effect of the conjugation in the molecule than in the case of the ketones, which may be connected with a disturbance of coplanarity. In a number of cases, the infrared spectra of the, -bis(5-nitro-2-furyl)polyalkenones exhibit splitting of the symmetrical and antisymmetrical vibrations of the nitro group.For part VII, see 1].Preliminary results of the present investigation were given for the first time at the 2-nd All-union Scientific Conference on the Chemistry of Furan Compounds, Saratov, 23–26 January, 1962, see 2].