Synthetic Route of 40872-87-5, The chemical industry reduces the impact on the environment during synthesis 40872-87-5, name is Methyl 3-amino-4-chlorobenzoate, I believe this compound will play a more active role in future production and life.
In one example of the inventive process, the reaction was conducted with methyl 3-amino-4-chloro-benzoate and 1-cyclopentyl-2-pyridinyl acetylene as the starting materials (Scheme 7). Suitable choices of ligand, base and solvent was important for obtaining satisfactory results as shown in Table 1. Several ligands were examined. It was found that the reaction proceeded smoothly to afford the desired indole product when using either ligand 4a, 4b or 5 in the presence of n-Bu4N+OAc-. The major side-reaction was homocoupling of the arylchloride via double amination (entries 1-3). The proper choice of base, solvent, temperature, and concentration was important to minimize the formation of the amination byproduct and also maximize the desired regioselectivity. By using inorganic bases such as K2CO3, a cleaner reaction could be obtained than by using n-Bu4N+OAc- as base. When a ferrocene ligand such as bis(diisopropylphosphino)ferrocene was employed, in combination with K2CO3 as base, the indolization of 2-chloroaniline with the internal acetylene completed rapidly, providing the product in high purity and regioselectivity (entry 4). Addition of LiCl or LiI as additive did not improve the yield. Instead, it slowed down the reaction (entries 5-6). With reduced catalyst loading (5 mol %), the reaction also proceeded smoothly and cleanly (entry 7). Changing the ratio of ligand to palladium acetate from 2:1 to 1:1 prolonged the reaction time (entry 8). Using K2CO3 as base, ligands 4a, 4b or 6 also afforded good results (entries 9-10). The wavelength used was 240 nm. TABLE I Base Time Entry (Scale) (eq) Catalyst (h) Result* 1 (100 mg) n-Pd(OAc)2 (10%) 4 Complete conversion of Bu4N+OAc- 2-(Di-t- starting material, giving 45 (2.5 eq) butylphosphino)- area % product and 33 biphenyl (40%) area % byproduct. 2 (100 mg) n-Pd(OAc)2 (10%) 3 Ratio of the desired product Bu4N+OAc- 1,1′- to starting material (2.5 eq) Bis(diphenylphosphino) (cholroaniline) was 5:1, ferrocene(20%) about 35 area % unknown impurities. The ratio of the regioisomers was 9:1. 3 (200 mg) n-Pd(OAc)2 (10%) 14 Complete conversion of the Bu4N+OAc- 1,1′-Bis(di-i- starting material, about 35 (2.5 eq) propylphosphino) area % of unknown ferrocene(20%) impurities. The ratio of the regioisomers was 9:1. 28% isolated yield was obtained through column chromatography for two steps. 4 (100 mg)K2CO3 (2.5 eq)Pd(OAc)2 (10%) 3 Complete conversion of the 1,1′-Bis(di-i- starting material. The propylphosphino) desired product was formed ferrocene(20%) in 88 area % purity. The ratio of the regioisomers was 20:1. 5 (100 mg)K2CO3 (2.5 eq)Pd(OAc)2 (10%) 5 Ratio of the desired product 1,1′-Bis(di-i- to the starting material was LiCl (1 eq) propylphosphino) 14:1. The ratio of the ferrocene(20%) regioisomers was 19:1. 6 (100 mg)K2CO3 (2.5 eq)Pd(OAc)2 (10%) 5 The ratio of the desired 1,1′-Bis(di-i- product to the starting LiI (1 eq) propylphosphino) material was 1.6:1. ferrocene(20%) 7 (100 mg)K2CO3 (2.5 eq)Pd(OAc)2 (5%) 14 The ratio of the desired 1,1′-Bis(di-i- product to the starting propylphosphino) material was 5:1. The ratio ferrocene(10%) of regioisomers was 18:1. 8 (100 mg)K2CO3 (2.5 eq)Pd(OAc)2 (5%) 14 The ratio of the desired 1,1′-Bis(di-i- product to the starting propylphosphino) material was 2.5:1. The ferrocene(6%) ratio of regioisomers was 19:1. 9 (100 mg)K2CO3 (2.5 eq)Pd(OAc)2 (5%) 14 Complete conversion of the 2-(Di-t- starting material, with about butylphosphino)- 20 area % impurities. The biphenyl (10%) ratio of the regioisomers was 20:1. 10 (100 mg)K2CO3 (2.5 eq)Pd(OAc)2 (5%) 14 The ratio of the desired Tricyclohexylphosphine product to the starting (10%) material was 4:1. Ratio of the regioisomers was 18:1. *Ratios of product were measured by HPLC analysis
In the field of chemistry, the synthetic routes of compounds are constantly being developed and updated. I will also mention this compound in other articles, Methyl 3-amino-4-chlorobenzoate, other downstream synthetic routes, hurry up and to see.
Reference:
Patent; Boehringer Ingelheim International GmbH; US2005/209465; (2005); A1;,
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