N－N－二甲基甲酰胺缩二甲醇对喋呤的甲基化反应

用N，N-二甲基甲酰胺缩二甲醇[（CH3）2NCH(OCH3)2，1]和蝶呤（2-氨基-4- 羟基蝶啶）衍生物在极性有机溶剂中反应一般得到脒化产物：N^2-(N，N-二甲基氨 基亚甲基)-蝶呤衍生物，但是在1，4-二氧六环中进行以上反应时发现，N，N-二甲 基酰胺缩二甲醇（1）不仅是脒化试剂，而且也是蝶呤化合物的甲基化试剂，并且 也依据蝶呤的N^2-位的不同取代基进行选择性的N(3)-或O^4-甲基化反应。

Methylation of pterins with n, n-dimethylformamide dimethylacetal

Treatment of pterin (2-amino-4-hydroxy-pteridine) derivatives with N,N-dimethylformamide dimethylacetal [1, (CH 3) 2NCH(OCH 3) 2] usually gave corresponding N 2-(N,N-dimethylaminomethylene)-pterin derivatives in polar solvents. It was found that in 1,4-dioxane N,N-dimethylformamide dimethylacetal (1) could be used as not only an amidining agent but also an methylating agent in pterin series and selective N(3)- or O 4-methylation was dependent on the substituent at the N 2-position of pterin.