| 摘要 |
An improved process for the production of <IMAGE> 2,4,5,6-tetraaminopyrimidine FROM <IMAGE> 2,4,6-triaminopyrimidine WHICH PRODUCES BUT DOES NOT ISOLATE AN INTERMEDIATE <IMAGE> 2,4,6-triamino-5-nitrosopyrimidine WHICH COMPOUND IS RETAINED IN SITU AND MINIMIZES THE COMPLEX POLYMER FORM OF A THREE-DIMENSIONAL NETWORK OF AZO LINKAGES FORMED BY THE NITROSO AND AMINO GROUPS. These groups, as they appear in the nitroso intermediate, have carcinogenic possibilities. It has been found that the nitroso compound will precipitate as a stirrable slurry if the temperature parameter is kept low at about 0 DEG -20 DEG C. A preferred route for the production of the nitroso compound from the triamino starting material utilizes as reactants 1.0-1.05 moles of sodium nitrite and 1.5 moles of HOAc in water (HCl may be substituted for HOAc). In the second state of this sequential reaction, the reduction of nitroso is carried out by a reducing agent and one preferred agent is sodium dithionite. Catalytic agents such as Raney nickel and hydrazine or nickel salts, e.g., nickel chloride, and sodium borohydride may also be used. The present process is an improvement in part of the technique of Piper and Montgomery, J. Het. Chem., 11:279 (1974), which process is designed specially to produce the antifolate methotrexate as an end product and is an improvement of the method of application Ser. No. 742,450 of Ellard filed Nov. 17, 1976, entitled "Improved Synthesis of Methotrexate", U.S. Pat. No. 4,080,825.
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