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. 1379338-74-5, name is 5,7-Dichloropyrido[3,4-b]pyrazine, A new synthetic method of this compound is introduced below., category: Pyrazines
Intermediate 37: 1,1-dimethylethyl 3-{[(7-chloropyrido[3,4-b]pyrazin-5-yl)amino]methyl}-4,4-difluoro-1-piperidinecarboxylate (Isomer 2) 5,7-Dichloropyrido[3,4-b]pyrazine (620 mg, 3.10 mmol) was dissolved in N-methyl-2-pyrrolidinone (NMP) (5 mL) and to this was added DIPEA (0.601 mL, 4.65 mmol) and 1,1-dimethylethyl 3-(aminomethyl)-4,4-difluoro-1-piperidinecarboxylate (776 mg, 3.10 mmol). This was heated in a microwave at 130 C. for 30 min. The reaction mixture was partitioned between ethyl acetate and water. The aqueous was re-extracted twice with ethyl acetate and the combined organic layers washed with brine, dried over a hydrophobic frit and concentrated in vacuo to yield a brown oil. It was dissolved in DCM and passed through silica (100 g) eluting with a 10-50% ethyl acetate in cyclohexane gradient. Appropriate fractions were combined and concentrated in vacuo to yield the title compound as a yellow solid, 1.0 g. Chiral separation was achieved (Sample preparation: Sample dissolved in ethanol (30 ml) sonicating and heating with air gun as required. 4-5 ml injections were then pumped onto a preparative scale Whelk-O(S,S) column (2 inch). Details as follows: Column-Whelk-O(S,S) (50×250 mm, 10 micron); Detection-UV DAD-300 nm (bandwidth 180 nm, reference 550 nm (bandwidth 100 nm)); Flow Rate-70 ml/min; Mobile Phase A: Heptane; Mobile Phase B: IPA; Isocratic method (premixed) 5% B; Runtime-60 min; Number of runs-8) to yield the title compound (second eluting peak from the chiral column) as a yellow solid (441 mg). LCMS (Method B): Rt=1.27 min, MH+=414 The following intermediate was obtained as the first eluting peak from the chiral separation above: Intermediate 38: 1,1-dimethylethyl 3-{[(7-chloropyrido[3,4-b]pyrazin-5-yl)amino]methyl}-4,4-difluoro-1-piperidinecarboxylate (Isomer 1) LCMS (Method B): Rt=1.27 min, MH+=414
The basis of chemical reaction formula synthesis, the synthesis route is composed of some specific reactions and combined according to certain logical thinking. We look forward to the emergence of more reaction modes in the future.