Bromide ion → Methyl 3,7-dimethyl-4-nitro-6-octenoate
Reaction equation
BrCCC=C(C)C.[Br-].[CH3:9][C:10](=[CH:12][CH2:13][CH2:14][N+:15]([O-:17])=[O:16])[CH3:11].N([O-])=O.[Na+].[C:22]([O:27][CH3:28])(=[O:26])/[CH:23]=[CH:24]/[CH3:25]>CS(C)=O>[CH3:25][CH:24]([CH:14]([N+:15]([O-:17])=[O:16])[CH2:13][CH:12]=[C:10]([CH3:11])[CH3:9])[CH2:23][C:22]([O:27][CH3:28])=[O:26]Participants
Procedure
The bromo compound, 8-bromo-2,6-dimethyl-5-[2-(tetrahydropyran-2-yloxy)]-2-octene, used to prepare the Grignard reagent in the first step in the synthesis is prepared by a series of reactions using 5-bromo-2-methyl-2-pentene as the starting material. The bromide is first converted to 2-methyl-5-nitro-2-pentene by reaction with sodium nitrite in dimethylsulfoxide. The nitro compound is then reacted with methyl crotonate to form methyl 3,7-dimethyl-4-nitro-6-octenoate. Reaction of the octenoate derivative with titanous chloride results in the formulation of the oxo compound, methyl 3,7-dimethyl-4-oxo-6-octenate. The oxo compound is then reacted with lithium aluminum hydride to form 3,7-dimethyl-4-hydroxy-6-octen-1-ol. The diol is converted to the mono-acetate by reaction with acetic anhydride and the mono-acetate is then converted to the tetrahydropyranyl derivative by reaction with dihydropyran. The tetrahydropyranyl derivative is converted to the corresponding alcohol by reaction with potassium carbonate in a mixture of methanol and water. The bromo compound is then obtained by reacting the alcohol 3,7-dimethyl-4-[2-(tetrahydropyran-2-yloxy)]-6-octen-1-ol with phosphorous tribromide or triphenylphosphine and carbon tetrabromide.
Workup
- customis prepared by a series of reactions
Sources & evidence
- ORD record
- ord-76f492b0bbb5461cb556f3145cfc0dfb
- Source dataset
- uspto-grants-1979_12
- Patent number
- US04177194
Reaction notes
Loading…