Electric Literature of 524955-09-7, Researchers who often do experiments know that organic synthesis is a process of preparing more complex target molecules from simple raw materials through one or more chemical reactions. Generally, it requires fewer steps,and cheap raw materials. 524955-09-7, name is 3-Chloro-4-(pyridin-2-ylmethoxy)aniline. A new synthetic method of this compound is introduced below.
Following hydrogenation to form the first aniline intermediate, acid catalyzed coupling was performed to prepare 4-[3-chloro-4-(2-pyridylmethoxy)anilino]-3-cyano-7-ethoxy-6-N-acetylaminoquinoline, as shown below: To perform the coupling reaction, the two reactants were heated together in alcohol at 65-78 C. over 4-6 hours, yielding the product. The reaction begins as an amber slurry and thickens to a lighter beige slurry as it approaches completion. Upon scaling up from 75 g to 350 g, it proved necessary to add a catalytic amount (0.025 eq.) of methanesulfonic acid to initiate the reaction. As a specific example, 4-chloro-3-cyano-7-ethoxy-6-N-acetylaminoquinoline (0.141 kg, 0.49 mole) was added to the mixture of Example 2, followed by ethanol (0.037 L) to give a suspension. A catalytic amount of methanesulfonic acid (1.17 g) was added at 20-25 C. The resulting slurry was heated to 70-75 C. and held for a minimum of 4 hours. Thickening of the slurry was evident after 1.5 hours. Following reaction completion, the mixture was cooled to room temperature and may be used ?as is? in the telescoped reaction of Example 4 below.; As solvents EtOH, DMF or other suitable solvent may be used. Experimental results obtained using different solvents and reaction conditions are shown in Table 3. Difficulty filtering the product of this step (noted in several entries on Table 3) was circumvented by not isolating the solid at this point, but telescoping the reaction with the next step. It has been found that on the order of 20 volumes of EtOH were necessary to achieve reasonable stirring, but that the reaction can proceed in only 10 volumes of DMF, without significant loss in purity. In Table 3, where the entry is labelled NI, the intermediate product was not isolated, but carried into the next reaction step. TABLE 3 Coupling Reaction Coupling Temp Time Yield Solvent Solvent ( C.) (h) (%) Comments IPA EtOH 78 4 85.4 contains impurity THF EtOH 78 4 90.5 v. slow filtration THF THF 68 4 NA Only 16% product formed THF EtOH 78 4 94.2 v. slow filtration EtOH IPA 82 5 NA No reaction EtOH MeOH 65 5 60.0 v. slow filtration THF EtOH 78 1.5 80.3 v. slow filtration (MeSO3H) THF EtOH 78 4 86.0 v. slow filtration THF EtOH 78 3 85.7 4 h filtration – hard, green (MeSO3H) coated solid on drying THF Dimethoxy 85 2 74.2 Faster filtration (<1 hr) ethane Nice yellow solid THF Diethoxy 85 5 - - Methane THF Dimethoxy 70 6 - - Ethane THF EtOH 78 6 96.6 Slow filtration THF DMF 78 0.5 65.6 Some product lost in filtrate (MeSO3H) THF DMF 70 8 NI See Note 1 (MeSO3H) THF EtOH 78 6 ND See Note 2 (MeSO3H) THF EtOH 78 4 NI Yield to the free base is (MeSO3H) 80.4%3/ THF EtOH 75 4 NI Yield to the free base is (MeSO3H) 83%3/ THF EtOH 75 4 NI Yield to the free base is (MeSO3H) 86%3/ NR = no reaction, NI = not isolated; ND = not determined; NA = not available 1. Carried through to the deprotection and generation of free base to give 69.5% overall yield. 2. The overall yield after the deprotection and generation of the free base is 76.1% 3This reaction was not filtered at all but taken as slurry to the next step.
At the same time, in my other blogs, there are other synthetic methods of this type of compound,524955-09-7, 3-Chloro-4-(pyridin-2-ylmethoxy)aniline, and friends who are interested can also refer to it.
Reference:
Patent; WYETH; US2006/270668; (2006); A1;,
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem