PAPER
Synthesis of Substituted 3-Alkenylpyrazolo[1,5-a]pyrimidines
13C NMR (CDCl3) d
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Table 2 Spectroscopic Data of Products 2, 3, 5 (continued)
Product
1H NMR (CDCl3) d, J (Hz)
5f
2.58 (s, 3 H, CH3), 2.60 (s, 3 H, CH3), 2.70 (s, 3 H, 13.4 (CH3), 17.1 (CH3), 24.8 (CH3), 51.4 (CH3), 103.7 (C), 109.3
CH3), 3.81 (s, 3 H, CH3), 6.60 (s, 1 H, H-6), 6.98 (d, [CH(C-6)], 114.3 [CH(=CH)], 134.6 [CH(=CH)], 145.3 (C), 147.4
1 H, J = 16, =CH), 7.86 (d, 1 H, J = 16, =CH) (C), 155.1 (C), 160.4 (C), 168.8 [C(C=O)]
5g
3.83 (s, 3 H, CH3), 7.26 (s, 1 H, H-6), 7.54 (d, 1 H, 51.4 (CH3), 104.0 [C(C-3)], 106.2 [CH(C-6)], 116.7 [CH(=CH)],
J = 19, =CH), 8.05 (d, 1 H, J = 19, =CH), 7.59–
8.27 (m, 15 H, ArH)
127.9 (CH), 128.8 (CH), 128.8 (CH), 129.2 (CH), 129.6 (CH), 129.6
(CH), 129.8 (CH), 130.4 (CH), 130.6 (C), 130.9 (CH), 132.3 (C),
135.0 [CH(=CH)], 136.9 (C), 147.1 (C), 148.7 (C), 157.3 (C), 157.4
(C), 168.8 [C(C = O)]
5h
5i
3.77 (s, 3 H, CH3), 6.87 (d, 1 H, J = 16, =CH), 7.39 51.5 (CH3), 106.1 [CH(H-6)], 107.2 [C(C-3)], 105.7 [CH(C-6)], 115.5
(s, 1 H, H-6), 7.95 (d, 1 H, J = 16, = C-H), 7.47–
8.15 (m, 10 H, ArH), 8.23 (s, 1 H, H-2)
[CH(=CH)], 127.5 (CH), 128.8 (CH), 129.0 (CH), 129.1 (C), 129.3
(CH), 130.9 (CH), 131.3 (CH), 134.4 [CH(=CH)], 136.7 (C), 145.6
[CH(H-2)], 147.6 (C), 157.6 (C), 168.4 [C(C=O)]
2.26 (s, 3 H, CH3), 2.61 (t, 2 H, J = 5.9), 4.25 (t, 2
45.0 (CH3), 57.8 (CH2), 61.8 (CH2), 105.9 (CH), 107.2 (C), 115.5
H, J = 5.9, CH2), 6.81 (d, 1 H, J = 15.8, =CH), 7.30 (CH), 127.4 (CH), 128.7 (CH), 128.9 (CH), 129.3 (CH), 130.9 (CH),
(s, 1 H, H-6), 7.39–7.48 (m, 6 H, ArH), 7.89–7.92 131.3 (CH), 134.5 (CH), 136.5 (C), 145.4 (C), 145.4 (CH), 147.4 (C),
(dd, 2 H, ArH), 7.91 (d, 1 H, J = 15.8, =CH), 8.16 (s, 147.5 (C), 157.4 (C), 167.8 (C)
1 H, H-2)
5j
2.73 (s, 3 H, CH3), 6.85 (d, 1 H, J = 16.2, =CH),
6.96 (s, 1 H, H-6), 7.59 (d, 1 H, J = 16.2, =CH),
7.48–8.10 (m, 10 H, ArH)
25.1 (CH3), 93.9 (C), 102.6 [CH(=CH)], 110.0 [CH(C-6)], 120.3 (C),
127.5 (C), 128.7 (CH), 128.8 (CH), 129.4 (CH), 129.4 (CH), 129.5
(CH), 130.3 (C), 131.4 (CH), 140.5 [CH(=CH)], 146.6 (C), 148.6 (C),
156.7 (C), 161.4 [C(CN)]
5k
5l
2.74 (s, 3 H, CH3), 6.86 (d, 1 H, J = 15.6, =CH),
6.98 (s, 1 H, H-6), 7.49 (d, 1 H, J = 15.6, =CH),
7.46–8.07 (m, 9 H, ArH)
25.1 (CH3), 94.5 [CH(=CH)], 102.6 (C), 110.2 [CH (C-6)], 120.1 (C),
128.8 (CH), 129.1 (CH), 129.5 (CH), 130.2 (C), 130.3 (CH), 130.6
(CH), 131.5 (C), 135.7 (C), 139.9 [CH(=CH)], 146.6 (C), 148.6 (C),
155.4 (C), 161.7 [C(CN)]
2.56 (s, 3 H, CH3), 6.73 (d, 1 H, J = 16.2, =CH),
7.44 (s, 1 H, H-6), 7.54(d, 1 H, J = 16.2, =CH),
7.56–8.19 (m, 10 H, ArH)
13.2 (CH3), 92.8 [CH(=CH)], 104.4 (C), 105.8 [CH(C-6)], 120.3 (C),
127.5 (CH), 128.9 (CH), 129.1 (CH), 129.5 (CH), 130.7 (C), 131.1
(CH), 131.5 (CH), 136.6, 139.7 [CH(=CH)], 147.2 (C), 148.5 (C),
155.5 (C), 157.9 [C(CN)]
5m
5n
5o
7.30 (s, 1 H, H-6), 7.41 (d, 1 H, J = 16.2, =CH),
7.55 (d, 1 H, J = 16.2, =CH), 7.19–8.21 (m, 15 H,
ArH), 8.29 (s, 1 H, H-2)
105.3 [CH(C-6)], 109.7 [C(C-3)], 117.7 [CH(=CH)], 126.0 (CH),
126.9 (CH), 127.2 (CH), 128.6 (CH), 128.7 (CH), 128.9 (CH), 129.2
(CH), 130.4 (CH), 131.0 [CH(=CH)], 131.3 (CH), 137.2 (C), 138.2
(C), 143.1 [CH (C-2)], 143.2 (C), 146.2 (C), 146.8 (C), 155.7 (C)
2.08 (d, 3 H, J = 1.5, =CCH3), 2.43 (s, 3 H, CH3),
2.61(s, 3 H, CH3), 3.80 (s, 3 H, OCH3), 6.72 (s, 1 H, [CH(C-6)], 128.2 (C), 128.7 (CH), 128.7 (CH), 129.3 (CH), 130.99
H-6), 7.51–7.54 (m, 3 H, C6H5), 7.71 (d, 1 H,
J = 1.5, =CH), 7.98 (dd, 2 H, C6H5)
13.9 (CH3), 15.8 (CH3), 24.9 (CH3), 51.9 (CH3), 104.4 (C), 108.3
[CH(=CH)], 131.3 (C), 145.8 (C), 146.9 (C), 154.2 (C), 159.0 (C),
169.1 (C)
3.63 (s, 3 H, CH3), 3.80 (s, 3 H, CH3), 3.82 (s, 2 H, 34.5 (CH2), 52.2 (CH3), 52.2 (CH3), 106.4 [CH(C-6)], 106.9 (C),
CH2), 7.39 (s, 1 H, H-6), 7.46–7.54 (m, 6 H, ArH), 120.7 (C), 127.5 (CH), 128.8 (CH), 129.0 (CH), 129.3 (CH), 130.8
7.96 (dd, 2 H, C6H5), 8.12 (dd, 2 H, ArH), 8.27 (s, 1 (C), 130.9 (CH), 131.1 (CH), 131.4 [CH(=CH)], 136.7 (C), 144.9
H, =CH), 8.29 (s, 1 H, H-2)
[CH(C-3)], 147.4 (C), 148.2 (C), 157.4 (C), 168.4 (C), 171.6 (C)
3-Bromo-5-methyl-2,7-diphenylpyrazolo[1,5-a]pyrimidine (6;
R1 = R3 = Ph, R2 = Me)
13C NMR (CDCl3): d = 25.0 (CH3), 81.9 (C), 109.3 [CH(C-6)],
128.4 (CH), 128.6 (CH), 128.9 (CH), 129.0 (CH), 129.4 (CH),
130.3 (C), 131.2 (CH), 132.1 (C), 146.1 (C), 147.5 (C), 152.4 (C),
160.1 (C).
A solution of 5-methyl-2,7-diphenylpyrazolo[1,5-a]pyrimidine (2a;
2.85 g, 10 mmol) and NBS (1.98 g, 11 mmol) in CCl4 (30 mL) was
stirred at 50 °C for 0.5 h. After cooling, the solution was filtered and
petroleum ether was added to the filtrate causing precipitation of 6.
The product was collected as light yellow crystals (3.15 g, 87%);
mp 136–138 °C.
Acknowledgment
We gratefully acknowledge financial support by Deutsche For-
schungsgemeinschaft, Fonds der Chemischen Industrie, and Elbion
GmbH.
1H NMR (CDCl3): d = 2.64 (s, 3 H, CH3), 6.77 (s, 1 H, H-6), 7.36–
8.44 (m, 10 H, ArH).
Synthesis 2004, No. 14, 2329–2334 © Thieme Stuttgart · New York