Allyl bromide → Methyl 2-Allyl-3-hydroxy-5-methoxybenzoate
Reaction equation
[CH2:1]([C:4]1C(OC)=CC(C(Cl)=O)=CC=1OC)[CH:2]=C.[CH3:17][O:18][C:19](=[O:29])[C:20]1[CH:25]=[C:24]([O:26][CH3:27])[CH:23]=[C:22]([OH:28])[CH:21]=1.C(Br)C=C.COC(=O)C1C=C(OC)C=C(OCC=C)C=1.COC(=O)C1C=C(OC)C(CC=C)=C(O)C=1>>[CH3:17][O:18][C:19](=[O:29])[C:20]1[CH:25]=[C:24]([O:26][CH3:27])[CH:23]=[C:22]([OH:28])[C:21]=1[CH2:4][CH:1]=[CH2:2]Participants
Procedure
4-Allyl-3,5-dimethoxy-benzoyl chloride. Starting from 3-hydroxy-5-methoxybenzoic acid methyl ester by reaction with allyl bromide, 3-allyloxy-5-methoxybenzoic acid methyl ester is prepared. B.p. 128°-30°C/0.4 mmHg. This compound is subjected to the allylic rearrangement performed as described by Tarbell in Organic Reactions, Vol. II, New York, 1944 and a mixture of 4-allyl-3-hydroxy-5-methoxybenzoic acid methyl ester and 2-allyl-3-hydroxy-5-methoxybenzoic acid methyl ester is obtained. By hydrolysis under alkaline conditions and separation by fractioned crystallization the pure 4-allyl-3-hydroxy-5-methoxybenzoic acid is obtained. M.p. 202°-3°C (from methanol). The reaction with dimethylsulfate according to the procedure described by F. Benington et al. in Journal Org.Chem. 25, 2066, 1960 affords the corresponding 4-allyl-3,5-dimethoxy-benzoic acid. M.p. 188°-90°C (from light petroleum). This compound is allowed to react with thionyl chloride and 4-allyl-3,5-dimethoxy-benzoyl chloride is prepared. M.p. 56°-57°C (from light petroleum).
Workup
- customis prepared
Sources & evidence
- ORD record
- ord-8c48428923294693b533df0a91db020f
- Source dataset
- uspto-grants-1976_08
- Patent number
- US03978065
Reaction notes
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