Table 1.

Formation of Cytidine 2′-Phosphate 5 with Varying Amounts of Cytosine

3: Cytosine	Temperature (°C)	Reaction time (day)	Yield of5(%)
1:1	100	1	1.7
		4	2.7
	85	1	0.4
		4	0.8
	125	1	2.8
1:2	100	1	3.5
		4	5.3
	85	1	0.4
		4	1.0
	125	1	5.9
1:3	100	1	3.8
		4	5.4
	125	1	7.7

A mixture of ribose 1,2-cyclic phosphate 3 (5 μL, 15 mM), cytosine (3.75 mM), and calcium chloride (8 μL,15 mM) in aqueous solution was dried and heated. The yield is based on the amount of limiting starting material.