98910-55-5

Upstream product

• 3350-78-5 3,3-Dimethylacryloyl chloride 
• 150-19-6 O-methylresorcine 
• 541-47-9 3-Methylbutenoic acid 

Downstream Products

• 98910-61-3 2,2-Dimethyl-5-methoxy-4-chromanone 
• 54874-23-6 1-(2-hydroxy-4-methoxyphenyl)-3-methylbut-2-en-1-one 
• 76348-96-4 3-methoxy-4(3-methylbut-2-enoyl)phenol 
• 20321-73-7 7-methoxy-2,2-dimethyl-4-chromanone 
• 119840-28-7 1-(2-hydroxy-6-methoxyphenyl)-3-methyl-2-buten-1-one 
• 17598-02-6 2,2 dimethyl 7 methoxychromene 

Relevant academic research and scientific papers

Bismuth(III) triflate catalyzed tandem esterification–Fries–oxa-Michael route to 4-chromanones

An efficient tandem reaction approach is described to prepare 4-chromanones from electron-rich phenols and 3,3-dimethylacrylic acid or trans-crotonic acid in boiling toluene using 20?mol?% bismuth(III) triflate as the catalyst. The reaction is also successful from the corresponding aryl esters of each of these acids under the same conditions. The procedure is convenient to perform, and 25–90% yields of products are realized following chromatography. A range of substrates is included (14 substrates for each acid) to help define the scope of the process. Additional experiments are reported, which confirm that the sequence of events involves (1) esterification, (2) Fries rearrangement and (3) oxa-Michael ring closure.

Expeditious photochemical reaction toward the preparation of substituted chroman-4-ones

A facile photochemical preparation of 5-, 6-, and 7-substituted chroman-4-ones from aryl 3-methyl-2-butenoate esters is described. The two-phase base-catalyzed method relies upon two consecutive processes in one-pot reaction through a photo-Fries rearrangement and a based-catalyzed intramolecular oxa-Michael addition to afford the desired products.

ON THE REACTION OF SUBSTITUTED PHENOLS AND 3-METHYLBUT-2-ENOIC ACID. A COMPARATIVE STUDY

A systematic and comparative study of the reaction of a series of substituted phenols and 3-methylbut-2-enoic acid in zinc chloride/phosphorus oxychloride and aluminum chloride/phosphorus oxychloride reveals that the formation of phenolic esters and 2,2-dimethyl-4-chromanones is strongly influenced by the substituents, their popsition on the aromatic ring of the starting phenols.Based on our study, a mixed Friedel-Crafts and Fries rearrangement mechanism is in operation in these reactions.

On the synthesis of substituted 2,2-dimethyl1-4-chromanones and related compounds

A systematic study of the reaction of a series of monosubstituted phenols 3 and 3-methylbut-2-enoic acid 4 in phosphorus oxychloride/zinc chloride revealed that the formation of 4-chromanones was strongly infuenced by the substituents and their position on the aromatic ring of the starting phenols.

STUDIES ON THE SYNTHESIS OF PRECOCENES. THE PHOTO-FRIES REARRANGEMENT OF ESTERS OF α,β-UNSATURATED CARBOXYLIC ACIDS AND META-OXYGENATED PHENOLS

The photo-Fries rearrangement of a series of aryl esters of α,β-unsaturated carboxylic acids 1a,b and 2 has been investigated, in order to explore the possibilities of this reaction as a key step in the synthesis of precocenes and related compounds.In all cases, the photolysis in hexane does not lead to any observable transformation, but in the presence of potassium carbonate takes place a migration of the acyl group to the two ortho-positions.Additionally, trans-cis photoisomerization occurs with the trans-butenoate 1b.The resulting o-hydroxyketones 4a, 4b, 4c, 5a, 5b, 5c, and 8 are easily and efficiently cyclized to the corresponding 4-chromanones 6a, 6b, 7a, 7b, and 9.A second photo-rearrangement is observed in the case of 9, although the yield is low, due to deactivation by the carbonyl group.Cyclization of 10 gives rise to the tricyclic dichromanone 11.Compounds 6a and 11 are reduced and subsequently dehydrated by known procedures to afford the active chromenes 3 and 12.