- A New Synthesis of 3-Bromo-2-methoxybenzoic Acid
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A convenient preparation of 3-bromo-2-methoxybenzoic acid (8) from 2-bromophenol via 3-bromo-2-methoxy-1-(1-propenyl)benzene (11) is presented.
- Pudleiner, Heinz,Laatsch, Hartmut
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- Preparation method for intermediates of new medicine Lusutrombopag resisting to thrombopenia
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The invention discloses a preparation method for intermediates of a new medicine Lusutrombopag resisting to thrombopenia. According to the invention, column chromatography of each step is avoided through an effective method with regard to preparation for an intermediate I, and in addition, bromo-compounds are used for replacing chloro-compounds in the step of ring closure, thus the ring closure has a quantitative yield and is quite easy to operate. In addition, the second carbonyl group and bromine are introduced stepwise, thus the two steps achieve a yield of more than 80%, and are stable and easy to repeat. Compared with the yield of 25-30% of the last two steps of the original research document, the yield is greatly increased, and the preparation method is simple and convenient to operate, and easy to repeat. According to the invention, synthesis for an intermediate II is realized with a quite high yield (70-80%) and an extremely short route through two effective strategies with regard to the intermediate II.
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Paragraph 0045-0046
(2017/08/15)
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- Mono- and disalicylic acid derivatives: PTP1B inhibitors as potential anti-obesity drugs
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A series of compounds containing one or two salicylic acid moieties were synthesized, and their efficacy to inhibit the phosphohydrolase activity of PTP1B examined. Some of the methylenedisalicylic acid derivatives were potent inhibitors of PTP1B. Of those derivatives, 3c exhibited about a 14-fold selectivity against TC-PTP, and this compound was tested in a mouse model for its efficacy to prevent diet-induced obesity. It effectively suppressed the increases in body weight and adipose mass, without any noticeable toxic effect. The compound also prevented increases in the plasma triglyceride, cholesterol, and nonesterified fatty acid concentrations; thus, expanding its therapeutic potential to other related metabolic diseases, such as hyperlipidemia and hypercholesterolemia.
- Shrestha, Suja,Bhattarai, Bharat Raj,Lee, Keun-Hyeung,Cho, Hyeongjin
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p. 6535 - 6548
(2008/04/12)
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- First general, direct, and regioselective synthesis of substituted methoxybenzoic acids by ortho metalation
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(Chemical Equation Presented) New general methodology of value in aromatic chemistry based on ortho-metalation sites in o-, m-, and p-anisic acids (1-3) (Scheme 1) is described. The metalation can be selectively directed to either of the ortho positions by varying the base, metalation temperature, and exposure times. Metalation of o-anisic acid (1) with s-BuLi/TMEDA in THF at -78°C occurs exclusively in the position adjacente to the carboxylate. On the other hand, a reversal of regioselectivity is observed with n-BuLi/t-BuOK. With LTMP at 0°C, the two directors of m-anisic acid (2) function in concert to direct introduction of the metal between them while n-BuLi/t-BuOK removes preferentially the proton located ortho to the methoxy and para to the carboxylate (H-4). s-BuLi/TMEDA reacts with p-anisic acid (3) exclusively in the vicinity of the carboxylate. According to these methodologies, routes to very simple methoxybenzoic acids with a variety of functionalities that are not easily accessible by other means have been developed (Table 1).
- Nguyen, Thi-Huu,Chau, Nguyet Trang Thanh,Castanet, Anne-Sophie,Nguyen, Kim Phi Phung,Mortier, Jacques
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p. 3419 - 3429
(2008/02/03)
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- Directed ortho-metalation of unprotected benzoic acids. Methodology and regioselective synthesis of useful contiguously 3- and 6-substituted 2-methoxybenzoic acid building blocks
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By treatment with s-BuLi/TMEDA at -78 °C, unprotected 2-methoxybenzoic acid is deprotonated exclusively in the position ortho to the carboxylate. A reversal of regioselectivity is observed when the acid is treated with n-BuLi/t-BuOK. These results are of general utility for the one-pot preparation of a variety of very simple 3- and 6-substituted 2-methoxybenzoic acids that are not easily accessible by conventional means. The potential usefulness of the method is demonstrated by the expedient synthesis of lunularic acid.
- Nguyen, Thi-Huu,Castanet, Anne-Sophie,Mortier, Jacques
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p. 765 - 768
(2007/10/03)
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- Marine Bacteria, I. - Synthesis of Pentabromopseudiline, a Cytotoxic Phenylpyrrole from Alteromonas luteo-violaceus
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A new synthesis of 2,3,4-tribromo-5-(3,5-dibromo-2-hydroxyphenyl)pyrrole (1a, pentabromopseudiline), an antibiotic, enzymeinhibitory and cytotoxic active constituent of the marine bacterium Alteromonas luteo-violaceus, is described.For investigation of structure-activity relationships further 2-phenylpyrroles are investigated.Key step in their synthesis is the Grignard reaction of 2-(1,3-dioxan-2-yl)ethylmagnesium bromide (9d) with benzoyl chlorides yielding γ-phenyl-γ-ketoaldehydes 24, and the Paal-Knorr cyclisation of the latter. - Key Words: Alteromonas luteo-violaceus / Bromopyrrole / Marine bacteria / Pentabromopseudiline
- Laatsch, Hartmut,Pudleiner, Heinz
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p. 863 - 882
(2007/10/02)
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