| 摘要 |
A process for preparing hydrochlorides of compounds of general formula (2): (wherein R1 is lower alkyl; R4 and R5 are each hydrogen or the like; Y1, Y2, Y3 and Y4 are each hydrogen or the like; and n is 0 or 1), characterized by converting a compound of general formula (1): (wherein X is halogeno) into a phthalimide, conducting the deblocking of the phthalimido group, conducting both the conversion of the resulting amino group into a carbamate group and the reduction of the nitro group in one pot, conducting both the conversion of the obtained compound into an acylthiourea and the hydrolysis of the resulting compound in one pot, alkylating the resulting thiourea group, removing the amino-protecting group with hydrochloric acid and an alcohol, and then crystallizing the resulting compound by the addition of an organic solvent without the removal of the hydrochloric acid and the alcohol. This process permits reduction in the number of steps as compared with those of the prior art, improvement in the working atmosphere by virtue of the use of safer reagents and solvents, enhancement in the safeness of working, and so on, thus being useful as an industrial process. |
