6-[(1E )-3-(2-Hydroxyphenyl)-3-oxoprop-1-enyl]-2-(methyl-
thio)pteridin-4(3H)-one 13e. From 1-(2-hydroxyphenyl)-2-
(triphenylphosphoranylidene)ethanone (500 mg, 1.26 mmol)
and 6a (234 mg, 1.05 mmol) in dichloromethane (20 ml) over
16 h. The yellow product was precipitated by the addition of
DME (289 mg, 0.85 mmol, 81%), mp >230 ЊC. Found
(FABMS: glycerol matrix): 341.0705. C16H13N4O3S (M + 1)
requires 341.0708. νmax(KBr) 3436, 3071, 2894, 1694, 1637,
1575, 1544, 1348 cmϪ1; δH(DMSO) 2.62 [3H, s, C(9)H3], 7.02
[2H, m, C(15)H & C(17)H], 7.58 [1H, m, C(16)H], 7.84 [1H, d,
J = 15.6 Hz, C(11)H], 8.04 [1H, m, C(18)H], 8.30 [1H, d,
J = 15.6 Hz, C(10)H], 9.38 [1H, s, C(7)H], 11.96 [1H, s,
C(14)OH], 13.25 [1H, br s, N(3)H]; δC(DMSO) 13.74 [C(9)],
118.15 [C(16)], 119.84 [C(17)], 122.02 [C(13)], 128.00 [C(11)],
131.14 [C(18)], 132.45 [C(4a)], 136.74 [C(16)H], 139.25 [C(10)],
146.43 [C(6)], 150.97 [C(7)], 154.72 [C(2)], 160.42 [C(8a)],
161.45 [C(14)], 163.01 [C(4)], 193.04 [C(12)]; λmax(MeOH) 412,
316, 273 nm.
cmϪ1; δH(DMSO) 1.33 [3H, t, J = 7.1 Hz, C(15)H3], 2.62 [3H, s,
C(9)H3], 4.34 [2H, q, J = 7.1 Hz, C(14)H], 7.79 [1H, d, J = 15.9
Hz, C(11)H], 7.92 [1H, d, J = 15.9 Hz, C(10)H], 9.23 [1H,
s, C(7)H], 13.30 [1H, br s, N(3)H]; δC(DMSO) 13.72 [C(9)],
14.27 [C(15)], 62.53 [C(14)], 125.98 [C(11)], 132.74 [C(4a)],
141.50 [C(10)], 145.38 [C(6)], 151.70 [C(7)], 155.04 [C(2)],
160.41 [C(8a)], 161.74 [C(13)], 163.52 [C(4)], 183.06 [C(12)];
λmax(MeOH) 396, 313 nm.
(2E )-3-[2-(Methylthio)-4-oxo-3,4-dihydropteridin-6-yl]prop-
2-enamide 13i. From freshly prepared 2-(triphenylphosphor-
anylidene)acetamide 14a (517 mg, 1.62 mmol) and 6a (300 mg,
1.35 mmol) in dichloromethane (25 ml) under a nitrogen over
6 h. The product precipitated as an amorphous yellow solid
(259 mg, 0.99 mmol, 73%), mp >230 ЊC. Found (FABMS:
glycerol matrix): 264.0559. C10H10N5O2S (M + 1) requires
264.0555. νmax(KBr) 3401, 3337, 3188, 3060, 2997, 2805,
1705, 1688, 1572, 1546, 1521, 1350 cmϪ1; δH(DMSO) 2.60
[3H, s, C(9)H3], 7.19 [1H, d, J = 15.6 Hz, C(11)H], 7.30 [1H, s,
1 × N(13)H], 7.60 [1H, d, J = 15.6 Hz, C(10)H], 7.84 [1H, s,
1 × N(13)H], 9.03 [1H, s, C(7)H], 13.13 [1H, br s, N(3)H];
δC(DMSO) 13.69 [C(9)], 128.64 [C(11)], 132.24 [C(4a)], 134.86
[C(10)], 146.84 [C(6)], 150.42 [C(7)], 154.41 [C(2)], 160.62
[C(8a)], 162.34 [C(4)], 166.27 [C(12)]; λmax(MeOH) 369, 302 nm.
(2E )-3-[2-(Methylthio)-4-oxo-3,4-dihydropteridin-6-yl]prop-
2-enal 13f. From (triphenylphosphoranylidene)acetaldehyde
(537 mg, 1.76 mmol) and 6a (361 mg, 1.62 mmol) in DMF
(15 ml) over 1 h. The yellow product was precipitated by the
addition of DME (286 mg, 1.15 mmol, 71%), mp 162–167 ЊC.
Found (HREIMS): 248.0379. C10H8N4O2S (Mϩ) requires
248.0368. νmax(KBr) 3056, 3004, 2915, 1705, 1687, 1578, 1546,
1368, 1250 cmϪ1; δH(DMSO) 2.60 [3H, s, C(9)H3], 7.15 [1H, dd,
J = 15.9 & 7.8 Hz, C(11)H], 7.89 [1H, d, J = 15.9 Hz, C(10)H],
9.26 [1H, s, C(7)H], 9.81 [1H, d, J = 7.8 Hz, C(12)H], 13.20 [1H,
br s, N(3)H]; δC(DMSO) 13.79 [C(9)], 132.47 [C(11)], 132.58
[C(4a)], 147.98 [C(10)], 145.72 [C(6)], 150.43 [C(7)], 155.01
[C(4)], 161.14 [C(8a)], 164.41 [C(4)], 194.82 [C(12)]; λmax(DMF)
358, 317 nm.
6-[(1Z )-2-Bromo-3-oxobut-1-enyl]-2-(methylthio)pteridin-
4(3H)-one 13j. From 1-bromo-1-(triphenylphosphoranylidene)-
acetone 14b (477 mg, 1.20 mmol) and 6b (222 mg, 1.00 mmol)
in DMF (10 ml) over 30 min. The product was isolated by
concentration of the DMF solution and precipitation with di-
chloromethane (243 mg, 0.71 mmol, 71%), mp 191–194 ЊC
(decomp.). Found: C, 39.0; H, 2.7; N, 16.1; S, 9.3; Br, 22.2.
C11H9N4O2SBr requires C, 38.72; H, 2.66; N, 16.42; S, 9.40; Br,
23.42%. Found (FABMS: glycerol–NBA matrix): 340.9704.
C11H10N4O2SBr (M + 1) requires 340.9708. νmax(KBr) 3435,
3068, 2926, 1703, 1688, 1574, 1543, 1518, 1360, 1181 cmϪ1;
δH(DMSO) 2.62 [3H, s, C(9)H3], 2.65 [3H, s, C(13)H3], 8.41
[1H, s, C(10)H], 9.37 [1H, s, C(7)H], 13.24 [1H, br s,
N(3)H]; δC(DMSO) 13.73 [C(9)], 26.77 [C(13)], 128.24 [C(11)],
132.28 [C(4a)], 137.77 [C(10)], 146.34 [C(6)], 151.17 [C(7)],
153.88 [C(2)], 160.08 [C(8a)], 163.52 [C(4)], 192.73 [C(12)];
λmax(MeOH) 374, 310 nm.
Ethyl (4E )-5-[2-(methylthio)-4-oxo-3,4-dihydropteridin-6-yl]-
3-oxopent-4-enoate 13g. From ethyl 3-oxo-4-(triphenyl-
phosphoranylidene)butanoate (843 mg, 2.16 mmol) and 6a
(400 mg, 1.80 mmol) in dichloromethane (20 ml) over 1 h. The
yellow product was precipitated by the addition of DME as a
mixture of two tautomers a and b (90 mg, 0.27 mmol, 15%), mp
219–221 ЊC. Found (FABMS: glycerol–NBA matrix): 335.0823.
C14H15N4O4S (M + 1) requires 335.0814. νmax(KBr) 3440,
3083, 2997, 2915, 1693, 1651, 1582, 1550, 1350, 1241 cmϪ1;
δH(DMSO) 1.20 [3H, t, J = 7.1 Hz, C(16)H3 of a], 1.25 [3H, t,
J = 7.1 Hz, C(16)H3 of b], 2.61 [6H, s, C(9)H3 of a & C(9)H3 of
b], 3.96 [2H, s, C(13)H2 of a], 4.13 [2H, q, J = 7.1 Hz, C(15)H2
of b], 4.21 [2H, q, J = 7.1 Hz, C(15)H2 of a], 5.59 [1H, s, C(13)H
of b], 7.23 [1H, d, J = 15.8 Hz, C(11)H of b], 7.30 [1H, d,
J = 16.1 Hz, C(11)H of a], 7.53 [1H, d, J = 15.8 Hz, C(10)H of
b], 7.79 [1H, d, J = 16.1 Hz, C(10)H of a], 9.11 [1H, s, C(7)H of
a], 9.19 [1H, s, C(7)H of b], 11.81 [1H, br s, C(12)OH], 13.21
[2H, br s, N(3)H of a & N(3)H of b]; δC(DMSO) 13.66 [C(9) of
b], 13.70 [C(9) of a], 14.41 [C(16) of a], 14.47 [C(16) of b], 60.75
[C(15) of a], 61.04 [C(15) of b], 47.48 [C(13) of a], 94.81 [C(13)
of b], 128.17 [C(11) of b], 130.58 [C(10) of b], 131.68 [C(11) of
a], 132.23 [C(4a) of b], 132.53 [C(4a) of a], 138.96 [C(10) of a],
145.95 [C(6) of a], 147.63 [C(6) of b], 150.48 [C(7) of a], 150.87
[C(7) of b], 154.22 [C(2) of a], 154.79 [C(2) of b], 160.52 [C(8a)
of a & C(8a) of b], 162.23 [C(12) of b], 167.54 [C(4) of a & C(4)
of b], 167.77 [C(14) of b], 173.23 [C(14) of a], 193.40 [C(12) of
a]; λmax(MeOH) 389, 312 nm.
tert-Butyl
(2Z )-2-bromo-3-[2-(methylthio)-4-oxo-3,4-di-
hydropteridin-6-yl]prop-2-enoate 13k. From tert-butyl bromo-
(triphenylphosphoranylidene)acetate 14c (738 mg, 1.62 mmol)
and 6a (300 mg, 1.35 mmol) in dichloromethane (15 ml) over 1
h. The product was isolated as an orange solid by evaporation
of the dichloromethane and digestion of the residue with tolu-
ene (374 mg, 1.01 mmol, 75%), mp 94–97 ЊC. Found: C, 42.9; H,
2.6; N, 24.8; S, 14.7. C8H6N4O2S requires C, 43.24; H, 2.72; N,
25.21; S, 14.43%. Found (FABMS: glycerol matrix): 223.0273.
C8H7N4O2S (M + 1) requires 223.0290. νmax(KBr) 3441,
3070, 2928, 1715, 1689, 1578, 1520, 1361, 1180 cmϪ1;
δH(DMSO) 1.54 [9H, s, 3 × C(14)H3], 2.62 [3H, s, C(9)H3], 8.27
[1H, s, C(10)H], 9.37 [1H, s, C(7)H], 13.24 [1H, br s, N(3)H];
δC(DMSO) 13.70 [C(9)], 27.87 [C(14)], 83.93 [C(13)], 119.47
[C(11)], 132.21 [C(4a)], 136.47 [C(10)], 146.02 [C(6)], 150.89
[C(7)], 153.87 [C(2)], 160.12 [C(8a)], 161.32 [C(4)], 163.41
[C(12)]; λmax(MeOH) 367, 308, 268 nm.
6-[(1Z )-2-Methoxy-3-oxobut-1-enyl]-2-(methylthio)pteridin-
4(3H)-one 13l. From 1-methoxy-1-(triphenylphosphoranyl-
idene)acetone 14d (800 mg, 2.30 mmol) and 6a (425 mg, 1.91
mmol) in dichloromethane (25 ml) over 4 h. The product pre-
cipitated as a yellow solid (538 mg, 1.84 mmol, 96%), mp >220
ЊC. Found (FABMS: glycerol matrix): 293.0703. C12H13N4O3S
(M + 1) requires 293.0708. νmax(KBr) 3433, 3064, 2911, 1705,
1685, 1577, 1543 cmϪ1; δH(DMSO) 2.47 [3H, s, C(13)H3], 2.62
[3H, s, C(9)H3], 3.84 [3H, s, C(14)H3], 7.01 [1H, s, C(10)H], 9.34
Ethyl (3E )-4-[2-(methylthio)-4-oxo-3,4-dihydropteridin-6-yl]-
2-oxobut-3-enoate 13h. From ethyl 2-oxo-3-(triphenylphosphor-
anylidene)propanoate (813 mg, 2.16 mmol) and 6a (400 mg,
1.80 mmol) in dichloromethane (25 ml) over 16 h. The yellow
product was precipitated by the addition of DME (167 mg,
0.52 mmol, 29%), mp 190–192 ЊC. Found (FABMS: glycerol
matrix): 321.0652. C13H13N4O4S (M + 1) requires 321.0658.
νmax(KBr) 3433, 3082, 2989, 2911, 1736, 1694, 1581, 1518, 1356
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 6 6 4 – 6 7 5
673