ETHYL 4,6-DICHLOROPYRIDAZINE-3-CARBOXYLATE

Step 3[00162j To a 350 mL nitrogen purged Schlenk flask containing Int2 (3.77 g, 20.47 mmol) was added phosphorus oxychloride (38 mL, 408 mmol). The vessel was sealed and heated to 100 °C for 3.5 hours. The reaction was cooled to room temperature and the excess phosphorus oxychloride was removed in vacuo. The crude oil was dissolved into chloroform, re-concentrated and then poured into ice water, rinsing with ethyl acetate.The two layers were transferred to a separatory funnel, separated and the aqueous layer extracted 3x with ethyl acetate. The combined organic layers were washed twice with water and once with brine (saturated aqueous sodium chloride) and then dried over sodium sulfate, filtered, concentrated and then purified by automated chromatography (5- 90percent EtOAc:hexanes), providing Int3 (3.64 g, 16.3 mmol). ‘H NMR (400MHz, chloroform-d) ö 7.70 (s, 1H), 4.55 (qd, J=7.1, 1.1 Hz, 2H), 1.46 (td, J=7.2, 0.9 Hz, 3H). LC retention time 0.79 [J]. MS(E) m/z: 221 (MHj.[0177j A mixture 5-5 (3.38 g, 18.3 mmol) in POC13 (35 ml) was heated at 95 °C for 5 hr.The excess POC13 was removed under vacuum, to the residue ice was added followed byethyl acetate. The organic phase was separated, washed with 5percent NaHCO3, dried over Na2SO4, and concentrated to give compound 5-6 as an oil (3.27 g)

Molecular Weight:221.04
XLogP3:2
Hydrogen Bond Acceptor Count:4
Rotatable Bond Count:3
Exact Mass:219.9806328
Monoisotopic Mass:219.9806328
Topological Polar Surface Area:52.1
Heavy Atom Count:13
Complexity:191
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes