5682-79-1

Usage

InChI:InChI=1/C9H12Br2O/c1-5(2)7(10)9(12)8(11)6(3)4/h1-4H3

Upstream product

• 64-17-5 ethanol 
• 73806-71-0 2,3,5,6-tetrabromo-2,6-dimethyl-heptan-4-one 
• 127-08-2 potassium acetate 
• 504-20-1 phorone 
• 110-86-1 pyridine 

Downstream Products

• 504-20-1 phorone 
• 71500-18-0 3-methyl-1-[4,4,5,5-tetramethyl-2-(2-methyl-propenyl)-cyclopent-1-enyl]-but-2-en-1-one 
• 1889-98-1 4,4,5,5-tetramethylcyclopentane-1,2,3-trione 
• 10035-10-6 hydrogen bromide 
• 1889-99-2 3-bromo-2-hydroxy-4,4,5,5-tetramethylcyclopent-2-enone 
• 73806-71-0 2,3,5,6-tetrabromo-2,6-dimethyl-heptan-4-one 

Relevant academic research and scientific papers

The thorpe-ingold effect in glutarimide derivatives. Part II

Differently substituted glutarimides, 3-methylglutarimide (12), 3,3-dimethylglutarimide (14) and 3,3,4,4-tetramethylglutarimide (18) were prepared and their reactivity towards aryllithiums was investigated. The influence of Thorpe-Ingold effect on the dis

Ene Reactions of Indane-1,2,3-trione (a Super-enophile) and Related Vicinal Tricarbonyl Systems

Indane-1,2,3-trione 1 is conveniently prepared in quantitative yield by the azeotropic drying of ninhydrin 2 using chlorobenzene as solvent.The central C=O group of the trione is extremely electrophilic and ene addition occurs at this site with a wide range of alkenes and with terminal alkynes in aprotic solvents at moderate temperatures (70-130 deg C).The reactivity of trione 1 is somewhat attenuated by the solvent, and the ene additions are consistently faster in chloroform than in tetrahydrofuran.Stereoselectivity, when relevant, appears largely to be dictated bysteric factors.Regiochemical control can be exercised if the ene contains two reaction sites.Isoprene and 2,4-dimethylpenta-1,3-diene, however, react by Diels-Alder rather than by ene addition; the adducts are the expected regioisomers 18 and 20, respectively.Attempts to catalyse the ene reactions with Lewis acids were unsuccessful.The analogous ene reactions of 4,4,5,5-tetramethyl-cyclopentane-1,2,3-trione 44, 4,4,6,6-tetramethylcyclohexane-1,2,3-trione 45, and 2,2-dimethyl-1,3-dioxane-4,5,6-trione ('oxo-Meldrum's acid') 46 were also briefly investigated.

Preparation of 3-bromo-2-hydroxy-4,4,5,5-tetramethylcyclopenta-2-enone

Bromination of large batches of 2,6-dimethyl-2,5-heptadiene-4-one below -20° C. followed by dehydrobromination without intermediate isolation and recrystallization to produce 3,5-dibromo-2,6-dimethyl-2,5-heptadiene-4-one which can be cyclized without isolation to high yields of 3-bromo-2-hydroxy-4,4,5,5-tetramethylcyclopenta-2-enone is disclosed.