New synthetic route towards 2,2‐dimethylchromene and synthesis of substituted 7‐(dimethylpropargyl)chromene

Abstract

Trifluoromethansufonic acid (TFA) was found a proper reagent for regioselectively ring closure of resorcinol to afford 7‐hydroxy‐2,2‐dimethyl‐2,3‐dihydrochromen‐4‐one 3. The propargylation of 3 gave rise to 2,2‐dimethyl‐7‐(2‐methylbut‐3‐yn‐2‐yloxy)‐2,3‐dihydrochromen‐4‐one 4. Condensation of 4 with substituted phenyl or benzyl Grignard reagents afforded substituted phenyl or benzylidene chromenes 6a‐d and 4‐(substitutedbenzylidene)‐3,4‐dihydro chromenes 8a‐e, respectively.

Insect Antifeedant Potential of Xanthohumol, Isoxanthohumol, and Their Derivatives

“…7-Hydroxy-2,2-dimethylchroman-4-one ( 2 ) was obtained in the reaction of 1,3-dihydroxybenzene with dimethylacrylic acid (DMAA) in the presence of zinc chloride in phosphorus oxychloride, followed by isomerization of the intermediate product according to a modified method of Alizadeh et al (80% of isolated yield). The spectroscopic data were consistent with those reported in the literature. , In the next step the purified product ( 2 ) was subjected to the Williamson ether synthesis with methyl iodide to give 7-methoxy-2,2-dimethylchroman-4-one ( 3 ), the spectroscopic data of which matched those reported by An et al The synthesis of 4-hydroxychalcone ( 11 ) and 4-ethyl-4′-methoxychalcone ( 13 ) was carried out according to the literature method under strongly basic conditions (KOH), using methanol as a solvent.…”

“…7-Hydroxy-2,2-dimethylchroman-4-one ( 2 ) was obtained in the reaction of 1,3-dihydroxybenzene with dimethylacrylic acid (DMAA) in the presence of zinc chloride in phosphorus oxychloride, followed by isomerization of the intermediate product according to a modified method of Alizadeh et al (80% of isolated yield). The spectroscopic data were consistent with those reported in the literature. , In the next step the purified product ( 2 ) was subjected to the Williamson ether synthesis with methyl iodide to give 7-methoxy-2,2-dimethylchroman-4-one ( 3 ), the spectroscopic data of which matched those reported by An et al The synthesis of 4-hydroxychalcone ( 11 ) and 4-ethyl-4′-methoxychalcone ( 13 ) was carried out according to the literature method under strongly basic conditions (KOH), using methanol as a solvent. Xanthohumol ( 14 ) was isolated using the earlier described method from spent hops, the residue of supercritical carbon dioxide hop extraction, which was delivered by the Supercritical Extraction Department of the New Chemical Syntheses Institute in Puławy, Poland.…”

“…Synthesis of Compounds. 7-Hydroxy-2,2-dimethylchroman-4one (2) was obtained in the reaction of 1,3-dihydroxybenzene with dimethylacrylic acid (DMAA) in the presence of zinc chloride in phosphorus oxychloride, followed by isomerization of the intermediate product according to a modified method of Alizadeh et al 47 (80% of isolated yield). The spectroscopic data were consistent with those reported in the literature.…”

Leishmanicidal Evaluation of Novel Synthetic Chromenes

“…Moreover, the biological potency of heterocyclic chromenes has been widely documented and considerable efforts have been made to explore new routes for the synthesis of therapeutically more efficient heterocyclic chromenes. In an investigation to find new anti-leishmanial agents which are structurally related to 2,2-dimethyl-2H-chromenes, a series of synthetic chromenes was prepared by a condensation reaction of chromene 1 and Grignard reagents [17,18]. The prepared compounds, namely compounds 1, 3, 4, and 6 -15 were tested against Leishmania major promastigotes.…”