3,5-Dihydroxybenzoic Acid → Benzoic acid, 3,5-dihydroxy-, ethyl ester
Reaction equation
[OH:1][C:2]1[CH:3]=[C:4]([CH:8]=[C:9]([OH:11])[CH:10]=1)[C:5]([OH:7])=[O:6].O[C:13]1C=C(C=C(O)[CH:20]=1)CO>C(O)C.S(=O)(=O)(O)O>[CH2:13]([O:6][C:5](=[O:7])[C:4]1[CH:3]=[C:2]([OH:1])[CH:10]=[C:9]([OH:11])[CH:8]=1)[CH3:20]Participants
Reactant 2
Product 1
Reagents, catalysts & solvents 2
Procedure
Synthesis of monomers was achieved from 3,5-dihydroxybenzoic acid or 3,5-dihydroxybenzyl alcohol as shown in above scheme. Commercially available 3,5-dihydroxybenzoic acid 1 was dissolved in ethanol along with catalytic amount of concentrated sulfuric acid and refluxed for 12 h to obtain ethyl-3,5-dihydroxybenzoate 1a. The ester 1a was then treated with one equivalent of alkyl halide to afford the mono alkylated ester 3 and 4. The yield of this reaction was rather low, because of the disubstituted byproduct obtained in the reaction along with the product as a statistical mixture. Compounds 3 and 4 were then reduced using LiAlH4 in dry THF under ambient temperature to give the monoalkylated phenols 3a and 4a. Compounds 2a and 5a were prepared by the reaction of 3,5-dihydroxybenzyl alcohol with 1 equivalent of alkyl halide under alkylation conditions. The phenols 2a-5a were then treated with tert-butylbromoacetate and sodium iodide to give compounds 2b-5b, which upon oxidation by PCC afforded the corresponding aldehydes 2c-5c. Treatment of aldehydes with methyl triphenylphosphonium bromide and potassium tert-butoxide under THF afforded the monomers 2d-5d. Polymers 2e-5e (n>1) was synthesized by nitroxide mediated living polymerization, using unimolecular intiator. The polymers were then hydrolyzed using potassium hydroxide as the base to afford carboxylic acid polymers 2f-5f.
Workup
- customSynthesis of monomers
- temperaturerefluxed for 12 h
Sources & evidence
- ORD record
- ord-bc61d2a95f58409589dd8d10016784fd
- Source dataset
- uspto-grants-2010_03
- Patent number
- US07687600B2
Reaction notes
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