Tricarbocyanines with dihydropyran, dihydrothiapyran, and N-methyltetrahydropyridine rings in chromophore was written by Tolmachev, A. I.;Slominskii, Yu. L.;Belaya, Zh. N.;Rodova, E. Z.. And the article was included in Khimiya Geterotsiklicheskikh Soedinenii in 1976.Synthetic Route of C6H8O2 This article mentions the following:
Tricarbocyanines with γ,γ’-oxydimethylene, -thiodimethylene, or -(methylimino)dimethylene bridges [I; R = H or (RR) = benzo; R1 = H, Cl; X = Br, iodine, p-MeC6H4SO3; X1 = O, S, NMe] were prepared from benzothiazolium salts and the resp. diformyl heterocyclic compound dianils, and their spectra determined The hetero atom in the bridge causes a slight hypsochromic shift in the spectra of both I and the dianil intermediates, presumably due to a neg. inductive effect. Protonation of the imino group magnifies the effect. In the experiment, the researchers used many compounds, for example, 5,6-Dihydro-2H-pyran-3-carbaldehyde (cas: 13417-49-7Synthetic Route of C6H8O2).
5,6-Dihydro-2H-pyran-3-carbaldehyde (cas: 13417-49-7) belongs to tetrahydropyran derivatives. Tetrahydropyrans and furans principally constitute as a central motif in diverse medicinally privileged molecules. One classic procedure for the organic synthesis of tetrahydropyran is by hydrogenation of the 3,4-isomer of dihydropyran with Raney nickel.Synthetic Route of C6H8O2
Referemce:
Tetrahydropyran – Wikipedia,
Tetrahydropyran – an overview | ScienceDirect Topics