Chloromethyl Methyl Ether → 5,6,7,8-Tetrahydro-5,5,8,8-tetramethyl-1-bromo-2-methoxymethoxynaphthalene-3-carboxylic acid
Reaction equation
CC1(C)CCC(C)(C)C2C=C(O)C(C(O)=O)=CC1=2.[CH3:19][C:20]1([CH3:37])[CH2:29][CH2:28][C:27]([CH3:31])([CH3:30])[C:26]2[C:25]([Br:32])=[C:24]([OH:33])[C:23]([C:34]([OH:36])=[O:35])=[CH:22][C:21]1=2.[CH3:38][O:39][CH2:40]Cl>>[CH3:19][C:20]1([CH3:37])[CH2:29][CH2:28][C:27]([CH3:30])([CH3:31])[C:26]2[C:25]([Br:32])=[C:24]([O:33][CH2:38][O:39][CH3:40])[C:23]([C:34]([OH:36])=[O:35])=[CH:22][C:21]1=2Participants
Procedure
5,6,7,8-Tetrahydro-5,5,8,8-tetramethyl-2-hydroxynaphthalene (Compound H, available in accordance with the publication Krause Synthesis 1972 140), is the starting material in the example shown in Reaction Scheme 2. Compound H is brominated to provide the corresponding 3-bromo compound (Compound I) which is thereafter protected in the hydroxyl function by treatment with methoxymethyl chloride (MOMCl) to yield 5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-3-methoxymethoxy-2-bromonaphthalene (Compound J). Compound J is reacted with t-butyllithium and carbon dioxide to provide the corresponding carboxylic acid (Compound K) from which the methoxymethyl protecting group is removed by acid to give 5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-hydroxynaphthalene-3-carboxylic acid (Compound L). Compound L is brominated to yield 5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-1-bromo-2-hydroxynaphthalene-3-carboxylic acid (Compound M). Compound L and Compound M serve as reagents in accordance with Formula 2. The hydroxy group of Compound M is protected for further transformations with methoxymethyl chloride (MOMCl) in the presence of base, yielding 5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-1-bromo-2-methoxymethoxynaphthalene-3-carboxylic acid (Compound N).
Sources & evidence
- ORD record
- ord-7d9c9f54ff15464bb6f377a4ab34ce6e
- Source dataset
- uspto-grants-2002_01
- Patent number
- US06342602B1
Reaction notes
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