Nonamethinecyanines with cyclic groups in the polymethine chain was written by Slominskii, Yu. L.;Radchenko, I. D.;Efimenko, N. I.;Tolmachev, A. I.. And the article was included in Ukrainskii Khimicheskii Zhurnal (Russian Edition) in 1980.Formula: C6H8O2 This article mentions the following:
Six bridged tetracarbocyanines (I; R = H or RR = benzo; R1 = Me, Et; X = I, ClO4; X1 = S, CMe2; X2 = direct link, CH2, O) with λmax ranging from 855 to 915 nm were prepared by condensation of the resp. II with heterocyclic quaternary compounds The II were prepd from PhNMeCH:CHCH:N+MePh I– [63899-31-0] and the appropriate cyclic aldehydes. The (CH2)2, (CH2)3, and CH2OCH2 bridges in I cause bathochromic shifts of 45, 128 and 15 nm, resp. In the experiment, the researchers used many compounds, for example, 5,6-Dihydro-2H-pyran-3-carbaldehyde (cas: 13417-49-7Formula: C6H8O2).
5,6-Dihydro-2H-pyran-3-carbaldehyde (cas: 13417-49-7) belongs to tetrahydropyran derivatives. Tetrahydropyrans are also used as important solvents, as chemical intermediate and as monomer for ring-opening polymerization. The reaction of tertiary 1,4- and 1,5-diols with cerium ammonium nitrate at room temperature gives tetrahydrofuran and tetrahydropyran derivatives in high yield and stereoselectivity. Various fragrant compounds have been synthesized using this method.Formula: C6H8O2
Referemce:
Tetrahydropyran – Wikipedia,
Tetrahydropyran – an overview | ScienceDirect Topics