反应详情

H2O (n=1) was prepared from glycyl-L-histidine and S-ethylisothiourea.H2SO4. Solutions of 1.50 g. of S-ethylisothiourea.H2SO4 in 5 ml of H2O and 1.74 g. of Gly-His.HCl in 3 ml of H2O were adjusted to pH 8-9 with 4 N NaOH. They were then mixed and kept at room temperature for a week. The cloudy suspension was filtered and the filtrate concentrated to dryness in vacuo. The residue, after addition of a small amount of EtOH, was dried in vacuo. A small amount of H2O was added to dissolve the dry residue and resulting solution was poured onto the column (2.5 cm i.d. × 30 cm Amberlite CG-120, 200-400 mesh, pyridine form). H2O, 1.0 M pyridine, 2.0 M pyridine, and 1.0 M pyridine--0.5 M NH4OH were used as the effluent solutions. Each fraction was tested for ninhydrin, Pauli, and Sakaguchi reactions. The fractions containing guanidinoacetyl-L-histidine were pooled and concentrated to dryness in vacuo. Cryst from H2O--EtOH; yield, 69.2%; mp, 108-111° C., decomp. Hydrolysis (6 N HCl, 110° , 24 hours.) gave guanidinoacetic acid and histidine, as confirmed be tlc. (thin layer chromatography).

1. additionThey were then mixed
2. waitkept at room temperature for a week
3. filtrationThe cloudy suspension was filtered
4. concentrationthe filtrate concentrated to dryness in vacuo
5. additionThe residue, after addition of a small amount of EtOH
6. customwas dried in vacuo
7. additionA small amount of H2O was added
8. dissolutionto dissolve the dry residue
9. customresulting solution
10. concentrationconcentrated to dryness in vacuo
11. customyield