Optimization of conditions for the model reaction^a.

Entry	Temperature (°C)	Time (min)	Isolated yield (%)
1	150	20	42
2	150	30	47
3	160	20	47
4	170	20	41
5	160	30	51
6	160	35	60
7	160	40	47
8b	160	35	45

^aThe reaction was performed using a Discover SP CEM microwave synthesizer with 1 mmol of 1a, 2.5 mmol of triethyl orthoacetate and 2.5 mmol of cyanamide in 2 mL of the ethyl acetate.

^bThe reaction was performed using 1 mmol of 1a, 3 mmol of triethyl orthoacetate and 3 mmol of cyanamide.