43120-28-1Relevant articles and documents
Regioselective N-alkylation of the 1H-indazole scaffold; ring substituent and N-alkylating reagent effects on regioisomeric distribution
Alam, Ryan M.,Keating, John J.
supporting information, p. 1939 - 1951 (2021/08/23)
The indazole scaffold represents a promising pharmacophore, commonly incorporated in a variety of therapeutic drugs. Although indazole-containing drugs are frequently marketed as the corresponding N-alkyl 1H- or 2H-indazole derivative, the efficient synthesis and isolation of the desired N-1 or N-2 alkylindazole regioisomer can often be challenging and adversely affect product yield. Thus, as part of a broader study focusing on the synthesis of bioactive indazole derivatives, we aimed to develop a regioselective protocol for the synthesis of N-1 alkylindazoles. Initial screening of various conditions revealed that the combination of sodium hydride (NaH) in tetrahydrofuran (THF) (in the presence of an alkyl bromide), represented a promising system for N-1 selective indazole alkylation. For example, among fourteen C-3 substituted indazoles examined, we observed > 99% N-1 regioselectivity for 3-carboxymethyl, 3-tert-butyl, 3-COMe, and 3-carboxamide indazoles. Further extension of this optimized (NaH in THF) protocol to various C-3, -4, -5, -6, and -7 substituted indazoles has highlighted the impact of steric and electronic effects on N-1/N-2 regioisomeric distribution. For example, employing C-7 NO2 or CO2Me substituted indazoles conferred excellent N-2 regioselectivity (≥ 96%). Importantly, we show that this optimized N-alkylation procedure tolerates a wide structural variety of alkylating reagents, including primary alkyl halide and secondary alkyl tosylate electrophiles, while maintaining a high degree of N-1 regioselectivity.
Preparation methods of 1H-indazol-3-carboxylic acid derivative, granisetron and lonidamine
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Paragraph 0072-0077; 0097-0102; 0122; 0133-0135, (2021/05/12)
The invention relates to preparation methods of a 1H-indazol-3-carboxylic acid derivative, granisetron and lonidamine. The 1H-indazol-3-carboxylic acid derivative is a compound with a structure shown in a formula (1) and a formula (2), and is mainly structurally characterized by having a 1H-indazol-3-carboxylic acid amide skeleton and a 1H-indazol-3-carboxylic ester skeleton. The 1H-indazol-3-carboxylic acid derivative can be synthesized by taking simple o-aminophenylacetic acid amide or o-aminophenylacetic acid ester as an initial raw material. The 1H-indazol-3-carboxylic acid derivative is a key intermediate for synthesizing a plurality of medicines, such as granisetron, lonidamine and the like. The synthesis method of the 1H-indazol-3-carboxylic acid derivative and the drug molecules glassetron and lonidamine is simple, the reaction condition is mild, the reaction speed is high, the yield is high, and purification is easy.
Substituted 3-indazole Mcl-1 protein inhibitor as well as preparation method and application thereof
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Paragraph 0029; 0039, (2020/07/28)
The invention discloses a substituted 3-indazole Mcl-1 protein inhibitor as well as a preparation method and application thereof. The compound has a structure represented by a general formula (I) which is described in the specification. The compound discl
