Highly Efficient and Broad-Scope Protocol for the Preparation of 7-Substituted 6-Halopurines via N-9-Boc-Protected 7,8-Dihydropurines

作者：Kotek Vladislav; Tobrman Tomas; Dvorak Dalimil^*

来源：Synthesis, 2012, 44(4): 610-618.

DOI：10.1055/s-0031-1290068

• alkylation
• acylation
• Michael addition
• nucleobases
• reduction

9-Boc-6-chloropurine, which can be obtained in high yield, is nearly quantitatively reduced with the THF center dot BH3 complex. The obtained 9-Boc-7,8-dihydropurine derivative is more stable compared to the corresponding 9-tritylpurine and can be smoothly N-7-alkylated, acylated, or it can serve as an N-nucleophile in conjugate additions. Deprotection with trifluoroacetic acid followed by MnO2 oxidation affords the N-7-substituted purines in high yields. The whole sequence of alkylation, deprotection, and oxidation can be done with crude intermediates using chromatography only for the purification of the final N-7-substituted purine.

• 出版日期2012-2