A closer look at the synthesis of 2-[18F]fluoroethyl tosylate to minimize the formation of volatile side-products

EJNMMI Radiopharmacy and Chemistry

Table 3 Yields of [¹⁸F]FEOH, [¹⁸F]VF and [¹⁸F]FEtOTs determined by radio-HPLC analysis of the crude product, obtained from the experimental plan of the rotatable central composite design

Entry	T (°C)	t (min)	[¹⁸F]FEOH (%)	[¹⁸F]VF (%)	[¹⁸F]FEtOTs (%)	[¹⁸F]VF/[¹⁸F]FEOH
1	70	3	1	2	61	2
2	70	15	5	16	74	3.2
3	130	3	7	26	60	3.7
4	130	15	11	28	60	2.6
5	100	9	7	23	59	3.3
6	100	9	5	20	61	4
7	100	9	5	18	62	3.6
8	100	10	5	23	59	4.6
9	79	9	2	13	62	6.5
10	121	9	5	20	52	4
11	100	5	3	11	67	3.7
12	100	13	8	25	58	3.1

Experimental standard deviation = 2. The base/precursor molar ratio was kept constant at 0.7

Entry	T (°C)	t (min)	[¹⁸F]FEOH (%)	[¹⁸F]VF (%)	[¹⁸F]FEtOTs (%)	[¹⁸F]VF/[¹⁸F]FEOH
1	70	3	1	2	61	2
2	70	15	5	16	74	3.2
3	130	3	7	26	60	3.7
4	130	15	11	28	60	2.6
5	100	9	7	23	59	3.3
6	100	9	5	20	61	4
7	100	9	5	18	62	3.6
8	100	10	5	23	59	4.6
9	79	9	2	13	62	6.5
10	121	9	5	20	52	4
11	100	5	3	11	67	3.7
12	100	13	8	25	58	3.1

Entry	T (°C)	t (min)	[¹⁸F]FEOH (%)	[¹⁸F]VF (%)	[¹⁸F]FEtOTs (%)	[¹⁸F]VF/[¹⁸F]FEOH
1	70	3	1	2	61	2
2	70	15	5	16	74	3.2
3	130	3	7	26	60	3.7
4	130	15	11	28	60	2.6
5	100	9	7	23	59	3.3
6	100	9	5	20	61	4
7	100	9	5	18	62	3.6
8	100	10	5	23	59	4.6
9	79	9	2	13	62	6.5
10	121	9	5	20	52	4
11	100	5	3	11	67	3.7
12	100	13	8	25	58	3.1

Entry	T (°C)	t (min)	[¹⁸F]FEOH (%)	[¹⁸F]VF (%)	[¹⁸F]FEtOTs (%)	[¹⁸F]VF/[¹⁸F]FEOH
1	70	3	1	2	61	2
2	70	15	5	16	74	3.2
3	130	3	7	26	60	3.7
4	130	15	11	28	60	2.6
5	100	9	7	23	59	3.3
6	100	9	5	20	61	4
7	100	9	5	18	62	3.6
8	100	10	5	23	59	4.6
9	79	9	2	13	62	6.5
10	121	9	5	20	52	4
11	100	5	3	11	67	3.7
12	100	13	8	25	58	3.1