The First Tandem Acetalization/5-<i>exo</i>-<i>dig</i> Cyclization of 6-Phenylethynylpyrimidine-5-carbaldehydes: Efficient Synthesis of 5-Alkoxy-(7<i>Z</i>)-7-benzylidene-5<i>,</i>7<i>-</i>dihydrofuro[3,4-<i>d</i>]pyrimidines
The first example of catalyst-free tandem acetalization/5-exo-dig cyclization reactions of 6-phenylethynylpyrimidine-5-carbaldehydes is presented. Efficient novel synthesis of 5,7-dihydrofuro[3,4-d]pyrimidine core is described.
The microwave-induced synthesis of pyrazolo[3,4-d]pyrimidines 4 in the reaction of N4-substituted-2,4-diamino-6-chloro-5-carbaldehydes 3 with hydrazine is described here. Precursors 3 have been prepared by the mono-amination of 2-amino-4,6-dichloropyrimidine-5-carbaldehyde 2 with aliphatic and aromatic amines. The reaction times with primary amines were relatively shorter than for secondary amines
这里描述了在N 4-取代的2,4-二氨基-6-氯-5-甲醛醛3与肼的反应中微波诱导的吡唑并[3,4- d ]嘧啶4的合成。前体3是通过2-氨基-4,6-二氯嘧啶-5-甲醛2与脂族和芳族胺的单胺化反应制备的。与伯胺的反应时间相对短于仲胺。