8-Oxa-bicyclo[3.2.1]oct-6-ene-3-carboxylic acid (6-amino-2,4-dioxo-1,3-dipropyl-1,2,3,4-tetrahydro-pyrimidin-5-yl)-amide → 8-(8-Oxa-bicyclo[3.2.1]oct-6-en-3-yl)-1,3-dipropyl-3,7-dihydro-purine-2,6-dione

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Reaction Steps

A solution of 8-oxa-bicyclo[3.2.1]oct-6-ene-3-carboxylic acid (6-amino-2,4-dioxo-1,3-dipropyl-1,2,3,4-tetrahydro-pyrimidin-5-yl)-amide (0.185 mmol, 0.067 g) in 20% NaOH (1.23 ml) and MeOH (6.2 ml) was stirred and refluxed overnight. The reaction was cooled to room temperature and then concentrated to remove MeOH. The aqueous residue was extracted with Et2O and these extracts discarded. The aqueous was acidified (pH 2-3) with conc. HCl and then extracted with EtOAc. The combined EtOAc extracts were washed with H2O and brine and dried (MgSO4). Filtration and evaporation followed by flash column chromatography, eluting with 1:1 EtOAc/CH2Cl2, provided the title compound (0.037 g, 58%) as a beige solid. 1H NMR (300 MHz, CDCl3): 0.93-0.99 (m, 6H), 1.62-1.83 (m, 6H), 2.14-2.25 (m, 2H), 3.40-3.51 (m, 1H), 4.05-1.10 (m, 4H), 4.86 (br s, 2H), 6.25 (s, 2H).

Provenance & Evidence