반응식
[Br:1][C:2]1[CH:10]=[C:9]([C:11]([OH:13])=[O:12])[CH:8]=[CH:7][C:3]=1[C:4](O)=[O:5].COC(=O)C1C=CC(C(OC)=O)=CC=1Br.BrC1C=C(C=O)C=CC=1C=O>>[Br:1][C:2]1[CH:10]=[C:9]([CH:8]=[CH:7][C:3]=1[CH2:4][OH:5])[C:11]([OH:13])=[O:12]참가 물질
실험 절차
A more general access to 3-alkyl-4-formyl-benzoic acids is given in the following section: Commercially available 2-bromo-terephthalic acid or 2-bromo-terephthalic acid dimethyl ester is transformed to 2-bromo-terephthalaldehyde via a reduction-oxidation sequence in analogy to litereture procedures (e.g. K. R. Roesch, H. Zhang, R. C. Larock, J. Org. Chem. (2001), 66, 8042-8051 (supporting information); T. Ise, D. Shiomi, K. Sato, T. Takui, Chemistry of Materials (2005), 17, 4486-4492; S, Narsimhan, K. G. Prasad, S. Madhavan, Synthetic Commun. (1995), 25, 1689-1697). 2-Bromo-terephthalaldehyde is then subjected to a Cannizzaro reaction according to a literature procedure (S. E. Hazlet, G. Bosmajian, J. H. Estes, E. F. Tallyn, J. Org. Chem. (1964), 29, 2034-2036) to give 3-bromo-4-hydroxymethyl-benzoic acid which is then oxidised for instance by treatment with MnO2 (lit. e.g. T. Ise, D. Shiomi, K. Sato, T. Takui, Chemistry of Materials (2005), 17, 4486-4492; S. Goswami, et al. Chem. Letters (2005), 34, 194-195) to 3-bromo-4-formyl-benzoic acid. This compound is then elaborated to the desired 3-alkyl-4-formyl-benzoic acid by either treating it with the appropriate alkenyl boron derivative (e.g. 2,4,6-trivinyl-cyclotriboroxane) under Suzuki conditions (Lit.: e.g. F. Kerins, D. F. O'Shea, J. Org. Chem. (2002), 67, 4968-4971) followed by catalytic hydrogenation or by reacting it with the appropriate alkyl-Zn reagents under Negishi conditions (e.g. H. Matsushita, E. Negishi, J. Org. Chem. (1982), 47, 4161-4165). The 4-formyl-group and the carboxylic acid function may require protection e.g. as an acetal and ester, respectively, during these transformations.
출처 및 근거
- ORD 기록
- ord-2694403eb13b4f2095a351052ead8135
- 출처 데이터셋
- uspto-grants-2013_04
- 특허 번호
- US08410151B2
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