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Please login or sign up for a free trial to access the full content. Variation 4: Cyclization with Diethoxymethyl Acetate

DOI: 10.1055/sos-SD-016-01192

Seela, F.; Ramzaeva, N.; Rosemeyer, H.Science of Synthesis, (200416973.

Diethoxymethyl acetate remains the best reagent for the preparation of 8-unsubstituted purines, with only a few side reactions being encountered.[‌207‌‌211‌] Treatment of commercially available 4,6-dichloropyrimidin-5-amine with 23 equivalents of (15N)ammonia in ethanol and diisopropylamine (200°C, 7atm, 12h) gives the monosubstituted product 4-chloropyrimidine-5,6[15N]-diamine (95% yield). The annulation reaction is performed in neat diethoxymethyl acetate (100°C, 3.5h) to give 6-chloro[9-15N]purine 36 (Scheme 29).[‌211‌]

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