Formaldehyde → HCID 178422344, compound

Participants

Reaction Steps

To 2-benzoylthio-6-(tert-butoxycarbonyl)-4,5,6,7-tetrahydropyrido[4,3-d][1,3]thiazole (2.44 g, 6.49 mmol) is gradually added dropwise a mixture of anisole (1.41 ml, 12.98 mmol) and trifluoroacetic acid (10.0 ml, 129.8 mmol) at 0° C., and after the addition, the mixture is warmed to room temperature and stirred for 30 minutes. The reaction solution is concentrated under reduced pressure, and to the resulting residue is added methylene chloride. The mixture is concentrated under reduced pressure again, and the resulting residue is crystallized from ether to give pale yellow crystals. The resulting crystals are suspended in THF (30 ml), and thereto is added a 37% aqueous formaldehyde solution (2.04 g, 25.2 mmol) at room temperature, and then further added thereto a 2N aqueous sodium hydroxide solution. The mixture is stirred for one hour, and thereto is added sodium cyanoborohydride (507 mg, 8.06 mmol), and the mixture is further stirred for additional one hour. To the reaction solution is added iN aqueous hydrochloric acid solution to make it weakly acidic, and the mixture is stirred for 30 minutes. The reaction solution is diluted with ethyl acetate, washed with a saturated aqueous sodium hydrogen carbonate solution, dried over sodium sulfate, and concentrated under reduced pressure. The residue is purified by silica gel column chromatography (methylene chloride/methanol=20˜10) to give 2-mercapto-6-methyl-4,5,6,7-tetrahydropyrido[4,3-d][1,3]thiazole (525 mg, yield; 44%) as pale yellow amorphous.

Provenance & Evidence