反应详情

Oxalyl chloride (2.9 g, 0.023 mole) is added dropwise to a stirred 0° C. solution of 3,5-bis(1,1-dimethylethyl)-4-hydroxycinnamic acid (4.3 g, 0.016 mole) in methylene chloride (30 ml) and N,N-dimethylformamide (0.5 ml . After one hour the solvent is removed in vacuo. The residue is dissolved in methylene chloride (30 ml) and added dropwise to a stirred 0° C. solution of 1,1-dimethylethyl hydrazinecarboxylic acid (4.5 g, 0.034 mole). 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 dissolved in methylene chloride (50 ml) and washed with aqueous 2M HCl, saturated aqueous NaCl, and dried MgSO4. Filtration and concentration gives a solid which was recrystallized from ethyl acetate/isopropyl ether to provide 4.6 g (6.1 g theor., 76%) of 1,1-dimethylethyl 2-[3-[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]-1-oxo-2-propenyl]hydrazinecarboxylic acid, mp 184° C.

1. customAfter one hour the solvent is removed in vacuo
2. dissolutionThe residue is dissolved in methylene chloride (30 ml)
3. additionAfter the addition
4. concentrationThe mixture is concentrated in vacuo
5. dissolutionthe residue dissolved in methylene chloride (50 ml)
6. washwashed with aqueous 2M HCl, saturated aqueous NaCl, and dried MgSO4
7. filtrationFiltration and concentration
8. customgives a solid which
9. customwas recrystallized from ethyl acetate/isopropyl ether