反应详情

Oxalyl chloride (11.5 g, 0.091 mole) is added dropwise to a stirred 0° C. solution of 3,5-bis(1,1-dimethyethyl)-4-hydroxybenzoic acid (15.0 g, 0.059 mole) in methylene chloride (120 ml) and N,N-dimethylformamide (0.5 ml). After one hour, the solvent is removed in vacuo. The residue is dissolved in tetrahydrofuran (70 ml) and added dropwise to a stirred 0° C. suspension of thiosemicarbazide (10.9 g, 0.120 mole) in tetrahydrofuran (300 ml). After the addition is complete the mixture is allowed to warm to room temperature and stir 18 hours. The mixture is concentrated in vacuo and the residue filtered through a plug of flash silica gel using a 1:1 ethyl acetate/heptane mixture as eluent. Concentration and trituration with 1:1 isopropyl ether/hexane yielded 17.6 g (19.4 g theor., 91%) of 2-[3,5-bis(1,1-dimethylethyl)-4-hydroxybenzoyl]hydrazinecarbothioamide, mp 210°-211° C.

1. customthe solvent is removed in vacuo
2. dissolutionThe residue is dissolved in tetrahydrofuran (70 ml)
3. additionadded dropwise to a stirred 0° C.
4. additionAfter the addition
5. concentrationThe mixture is concentrated in vacuo
6. filtrationthe residue filtered through a plug of flash silica gel using a 1:1 ethyl acetate/heptane mixture as eluent
7. concentrationConcentration and trituration with 1:1 isopropyl ether/hexane