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infrared pyrometer. The vessel contents were stirred by means of an adjustable
rotating magnetic plate located below the floor of the microwave cavity and a
Teflon-coated magnetic stir bar inside the vessel. Temperature, pressure, and
power profiles were monitored in both cases through the EASY-Control
software provided by the manufacturer.
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especially designed for synthetic chemistry. Start SYNTH™ (Milestone S.r.l.
Italy) is a multi-mode cavity with a microwave power delivery system ranging
from 0 to 1200 W. Open vessel experiments were carried out in a 250 mL round
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14. Typical procedure for the synthesis of N-arylpyrido[20,30:4,5]furo[3,2-
d]pyrimidin-4-amines (1a–i): A mixture of N0-(2-cyanofuro[3,2-b]pyridin-3-
yl)-N,N-dimethyl formimidamide 8 (0.1 g, 0.47 mmol) and appropriate aniline
(1.0 equiv) in acetic acid (2 mL) was irradiated at 118 °C (400 W, 3 min ramp).
On completion (followed by thin-layer chromatography), the reaction was
cooled to room temperature and water was added. The powder was filtered off,
washed with water and dried. The crude powder was purified by column
chromatography over silica gel using a gradient of petroleum ether/ethyl
acetate (100:0 to 0:100, v/v) as the eluent to give the desired compounds.
bottomed flask fitted with
a reflux condenser. The temperature can be
monitored via a fibre-optic contact thermometer protected in a Teflon coated
ceramic well inserted directly in the reaction mixture or via contact-less