2-Iodo-5-Methoxy-thiazolo[5,4-b]pyridine synthesis

Yield:1246093-96-8 30%

Reaction Conditions:

Stage #1: 5-methoxythiazolo[5,4-b]pyridin-2-aminewith toluene-4-sulfonic acid in acetonitrile at 0; for 0.25 h;
Stage #2: with potassium iodide;sodium nitrite in water;acetonitrile at 0 - 20; for 4 h;

Steps:

Preparation of 2-iodo-5-snethoxythiazolo[5,4-b]pyridine (10).

For 0 °C is provided with a magnetic stirring bar to 25 ml round-bottom flask by adding in ACN (4.0 ml), PTSA (0.79g, 4 . 14mmol) and 9 (0.25g, 1 . 38mmol), and stirring 15 minutes. Adding NaNO ₂ (0.19g, 2 . 76mmol) and KI (0.57g, 3 . 45mmol) in H ₂ O (0.9 ml) the solution, and stirring the mixture at room temperature for 4 hours. Added to the reaction mixture is then H ₂ O (15 ml) in, using saturated NaHCO ₃ adjusted to alkaline (pH=9), and add Na ₂ S ₂ O ₃ (2M, 3mL). The resulting reaction mixture with EtOAc (3x20mL) extraction. The combined organic extract water (20 ml), brine (20 ml) washing, through MgSO ₄ drying and vacuum concentration. Residue through silica gel (using EtOAc: hexane (1:4) as eluant) further purification, is 10 (0.12g, 30%), as a white crystalline solid.

References:

CN102985411,2016,B Location in patent:Paragraph 0407-0410