Synthesis of 2‐(4‐quinazolinyl)ethyl sulfides via addition of thiols to 4‐vinylquinazolines

Abstract

Reaction of vinyl and isopropenyl Grignard reagents with quinazoline results in addition to the 3,4‐imine bond to give the 4‐alkenyldihydroquinazolines 4 which are conveniently aromatized with potassium ferri‐cyanide to the 4‐alkenylquinazolines 5. Quinazolines 5 undergo addition with thiols under neutral conditions to afford the quinazolinylethyl sulfides 2 in moderate yields.

Synthesis of 4‐substituted 2‐(4‐methylpiperazino)pyrimidines and quinazoline analogs as serotonin 5‐HT2A receptor ligands

“…While 2‐chloro‐4‐vinylpyrimidine (30) has been obtained previously using cumbersome chemistry [23], its quinazoline analog 36 is a new compound. In the synthesis of 36, the general protocol was modified in that the intermediate 2‐chloro‐4‐vinyl‐3,4‐dihydroquinazoline (data not shown) was aromatized by the reaction with potassium ferricyanide, which has previously been used for the oxidation of 4‐vinyl‐3,4‐dihydroquinazoline [24]. The standard treatment of the adduct with DDQ resulted in opening of the pyrimidine subunit, which was previously demonstrated [4].…”

Synthesis and Structure-Activity Relationship Analysis of 5-HT7 Receptor Antagonists: Piperazin-1-yl Substituted Unfused Heterobiaryls

“…The starting material, 2-chloro-4-vinylquinazoline, was obtained by the reaction of 2-chloroquinazoline with vinyllithium followed by aromatization of the resultant 4-vinyldihydroquinazoline adduct by treatment with potassium ferricyanide(III) according to the described procedure [36].…”

Synthesis and acaricidal activity of 4‐pyrimidinyloxy‐ and 4‐pyrimidinylaminoethylphenyl dioxolanes and oxime ethers

“…1,2 Several modern acaricides, which reached the market recently, such as fenazaquin, 3 tebufenpyrad, 4 fenpyroximate, 5 pyridaben 6 and pyrimidifen, 7 as well as the natural product rotenone, interrupt mitochondrial electron transport by inhibition of NADH:ubiquinone oxidoreductase (complex I). 8±12 Although several derivatives of fenazaquin (Fig 1; I) have been described already, 13,14 we found during the course of a research programme that substitution of fenazaquin's tert-butyl group by a dioxolane ring (general structure II) or an oxime function (general structure III) leads to new acaricides, which are highly effective against spider mites of major importance, like the two-spotted spider mite, Tetranychus urticae (Koch), and the European red mite, Panonychus ulmi (Koch). The new compounds display outstanding contact activity on mobile stages of the mites and in addition possess moderate ovicidal properties.…”