Methanol → Methyl 6-chloro-3-methyl-[1,2,4]triazolo[4,3-b]pyridazine-8-carboxylate

HRID 521566Notes

Reaction equation

HRID 521566 reaction equation
S(Cl)(Cl)=O.[Cl:5][C:6]1[CH:7]=[C:8]([C:16]([OH:18])=[O:17])[C:9]2[N:10]([C:12]([CH3:15])=[N:13][N:14]=2)[N:11]=1.[CH3:19]O>>[Cl:5][C:6]1[CH:7]=[C:8]([C:16]([O:18][CH3:19])=[O:17])[C:9]2[N:10]([C:12]([CH3:15])=[N:13][N:14]=2)[N:11]=1

Participants

4

Reactant 3

HCID 887MethanolHCID 24386Thionyl ChlorideHCID 729431896-Chloro-3-methyl-[1,2,4]triazolo[4,3-b]pyridazine-8-carboxylic acid

Product 1

HCID 89287517Methyl 6-chloro-3-methyl-[1,2,4]triazolo[4,3-b]pyridazine-8-carboxylateYield 71.8%

Conditions

Temperature
80 °C

Procedure

Thionyl chloride (2.0 mL) was added to a solution of product 6-chloro-3-methyl-[1,2,4]triazolo[4,3-b]pyridazine-8-carboxylic acid (4.0 g, 18.5 mmol) in MeOH dropwise under cooled ice-bath. The resulting mixture was stirred at 80° C. for 16 hours and then cooled to room temperature and concentrated in vacuum. The crude product was purified by flash column chromatography (silica-gel, PE: EA=3:1) to give product methyl 6-chloro-3-methyl-[1,2,4]triazolo[4,3-b]pyridazine-8-carboxylate as a yellow solid (3.0 g, 71.8%). 1H NMR (300 MHz, CD3OD) δ: 7.92 (s, 1H), 4.07 (s, 3H), 2.79 (s, 3H). LRMS (M+H+) m/z: calcd 227; found 227.

Workup

  1. temperaturecooled to room temperature
  2. concentrationconcentrated in vacuum
  3. customThe crude product was purified by flash column chromatography (silica-gel, PE: EA=3:1)

Sources & evidence

ORD record
ord-aba90abcde4041ad93b34a7701d803c0
Source dataset
uspto-grants-2016_05
Patent number
US09328117B2

Reaction notes

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