The clear filtrate was allowed to stand overnight, whereupon colorless crystals precipitated. The supernatant solution was then decanted off, and the crystals were rinsed with acetonitrile (3 × 3 mL). The crystals were then dried under vacuum yielding the product, a mixture of 3 and 4 as a white, crystalline solid (0.65 g). Proton NMR integration gives a 2.3:1 ratio of 3 to 4. In the glovebox, a Schlenk tube was charged with (P 2 O 5 ) ∞ (0.19 g, 1.4 mmol) and acetonitrile (10 mL). To this suspension was then added pyridine (1.1 mL, 14 mmol). The vessel was then sealed and removed from the glovebox. The vessel was then placed in an oil bath and the mixture stirred at 70 • C overnight. The vessel was then cooled to room temperature and returned to the glovebox. The fine white precipitate was collected by filtration and rinsed thoroughly with acetonitrile. Drying the solid under vacuum yielded the product as a free flowing white powder (0.36 g, 1.1 mmol, 82% yield). The resulting product is poorly soluble in dichloromethane, chloroform, and pyridine (approximately 1 to 5 mg/mL) and not appreciably soluble in acetonitrile. Heating this material to 180 In the glovebox, 5 (0.11 g, 0.36 mmol) was suspended in dichloromethane (4 mL). To this stirring suspension was added DBU (0.22 g, 1.5 mmol) in dichloromethane (2 mL). The resulting suspension was stirred for 30 min, resulting in dissolution of most of the solid material. The resulting mixture was filtered through Celite® to remove insoluble material. All volatile materials were then evaporated under reduced pressure, leaving a pale yellow solid. The solid residue was then dissolved in acetonitrile (2 mL) and diethyl ether (15 ml) was added, resulting in a cloudy suspension. The next day, the mixture had settled into a polycrystalline solid. The supernatant was decanted off the crystals, and the solids were rinsed with diethyl ether. The resulting solid was dried under vacuum, giving the product as a white powder (0.10 g, 0.23 mmol, 65% yield). Treatment of either a mixture of 3 and 4 or 5 with diethylamine leads immediately to 7 which is purified with a simple workup.