Page 5 of 7
Journal of Medicinal Chemistry
mL, 2.9 mmol) was added dropwise over 15 min. Et3N (0.77 mL,
(1H, m, CH2ArO-H), 7.30 (2H, t, J = 7.9 Hz, Ph-H), 7.22-7.12 (3H,
1
2
3
4
5
6
7
8
5.8 mmol) was then added at -78 °C and the mixture was stirred
for 30 min. The solution was then allowed to warm up to room
temperature over 2 h. Solvent was then removed under reduced
pressure and the remaining white precipitate suspended in
anhydrous Et2O (50 mL). This was filtered and the filtrate
evaporated under reduced pressure, yielding the crude product
m, Ph-H), 6.34 (1H, dd, J = 3.4, 1.8 Hz, CH2ArO-H), 6.32 (1H, d, J
= 2.8 Hz, CH2ArO-H), 6.04 (1H, t, J = 5.0 Hz, 1’-H), 4.80 (2H, br s,
NHCH2), 4.70-4.60 (1H, m, 2’H), 4.46-4.30 (3H, m, 3’H/5’H2),
4.29-4.23 (1H, m, 4’-H), 3.95-3.77 (2H, 2 m, CHCH3), 3.61 (3H, s,
OCH3), 1.30-1.27 (3H, m, CHCH3); 13C NMR (100 MHz, MeOD) δ
175.5 (COOCH3), 154.0 (ArN-CH), 153.4 (ArO-C), 152.1 (Ph-C),
150.3 (ArN-C), 143.4 (ArO-CH), 140.7 (ArN-CH), 130.7, 126.2, 121.9
(Ph-CH), 120.9 (ArN-C), 111.4, 108.2 (ArO-CH), 90.0 (1’-C), 84.4
(4’-C), 75.4 (2’-C), 71.6 (3’-C), 67.3 (5’-C), 52.7 (OCH3), 51.4
(CHCH3), 38.4 (NHCH2), 20.3 (CHCH3); HRMS-ESI (m/z): Calc.
for C25H29N6O9NaP [M + Na]+ 611.1631, found 611.1633; Found: C
51.2, H 5.3, N 14.2 Calc. for C25H29N6O9P: C 51.0, H 4.97, N 14.3 %.
as
a
light brown oil. Purification via flash column
chromatography gave the pure product as a colourless oil (729
mg, 91%); (Eluent 7:3 EtOAC:hexane); 31P NMR (120 MHz, CDCl3)
1
9
δ 7.94, 7.62; H NMR (400 MHz, CDCl3) δ 7.45-7.33 (2H, m, Ar-
H), 7.31-7.21 (3H, m, Ar-H), 4.62-4.52 (1H, m, N-H), 4.26-4.14 (1H,
m, CHCH3), 3.79, 3.77 (2H, 2 s, OCH3), 1.51 (3H, dd, J = 7.1, 4.1 Hz,
CHCH3); 13C NMR (100 MHz, CDCl3) δ 173.4 (COCH3), 150.1 (Ar-
COP), 130.3, 126.4, 121.0 (Ar-CH), 53.3 (OCH3), 51.1 (CHCH3), 20.9
(CHCH3).
Phenyl-(tert-butyloxy-L-alaninyl)-phosphorochloridate
(7).16 Prepared as described for compound 6 using L-alanine
tert-butyl ester hydrochloride (400 mg, 2.20 mmol), phenyl
phosphorodichloridate (0.30 mL, 2.20 mmol) and Et3N (0.60 mL,
4.4 mmol). Product 7 was obtained as a pale yellow oil, which
was used in sequential steps without further purification (803
mg, 114%). 31P NMR (120 MHz, CDCl3) δ 8.26, 7.84; 1H NMR (400
MHz, CDCl3) δ 7.44 -7.32 (2H, m, Ar-H), 7.30-7.20 (3H, m, Ar-H),
4.28 (1H, br s, NH), 4.12-3.98 (1H, m, CHCH3), 1.56-1.34 (3H, m,
CHCH3, 9H, m, OCtBu); 13C NMR (100 MHz, CDCl3) δ 171.9
(COCOtBu), 149.9 (Ph-COP), 130.0, 126.1, 120.1 (Ph-CH), 82.9
(OCtBu), 51.0 (CHCH3), 28.1 (OCtBu), 20.8 (CHCH3).
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Phenyl-(tert-butyloxy-L-alaninyl)
kinetin
riboside
phosphoramidate (12). Prepared as described for compound 11
KR 2 (200 mg, 0.60 mmol), NMI (0.22 mL, 3.00 mmol) and 7 (552
mg, 1.80 mmol). The crude product was purified via flash column
chromatography to yield the final product as a white solid (52
mg, 14%); (Eluent 3:97 to 5:95 MeOH:CH2Cl2); 31P NMR (120
MHz, MeOD) δ 3.91, 3.84; 1H NMR (400 MHz, MeOD) δ 8.22
(1H, s, ArN-CH), 8.22, 8.19 (1H, 2 s, ArN-CH), 7.43 (1H, dd, J = 1.9,
0.9 Hz, CH2ArO-H), 7.35-7.26 (2H, m, Ph-H), 7.21-7.10 (3H, m,
Ph-H), 6.34 (1H, dd, J = 3.2, 1.9 Hz, CH2ArO-H), 6.32-6.30 (1H, m,
CH2ArO-H), 6.05-6.02 (1H, m, 1’-H), 4.79 (2H, s, NHCH2), 4.65
(1H, t, J = 5.2 Hz, 2’H), 4.48-4.30 (3H, m, 3’-H/5’H2), 4.29-4.24
(1H, m, 4’-H), 3.82-3.75 (1H, m, CHCH3), 1.39 (9H, s, t-Bu-H), 1.23
(3H, dd, J = 7.1, 1.2 Hz, CHCH3); 13C NMR (100 MHz, MeOD) δ
172.9 (CO), 154.3 (ArN-C), 152.6 (ArNC-H), 151.8 (ArO-C), 150.7
(PhCOP), 148.6 (ArN-C), 142.0 (ArOC-H), 139.3 (ArNC-H), 129.4,
124.7, 120.0 (PhC-H), 119.2 (ArN-C), 110.0, 106.8 (ArOC-H), 88.6
(1’-C), 83.0 (4’-C), 81.2 (OCtBu), 74.0 (2’-C), 70.2 (3’-C), 65.7 (5’-
C), 50.8 (CHCH3), 37.1 (NHCH2), 26.8 (3C, OCtBu), 19.1 (CHCH3);
HRMS-ESI (m/z): Calc. for C28H35N6O9NaP [M + Na]+ 653.2101,
Phenyl-(benzyloxy-L-alaninyl)-phosphorochloridate (8).16
Prepared as described for compound 6 using L-alanine benzyl
ester hydrochloride (500 mg, 2.32 mmol), phenyl
phosphorodichloridate (0.35 mL, 2.32 mmol) and Et3N (0.63 mL,
4.64 mmol). Product 8 was obtained a pale yellow oil (505 mg,
1
95%). 31P NMR (120 MHz, CDCl3) δ 7.85, 7.49; H NMR (400
found 653.2104; Found:
C
53.4,
H
5.6,
N
13.5 Calc. for
MHz, CDCl3) δ 7.40-7.32 (m, 5H, Ph-H), 7.28-7.21 (m, 5H, Ph-H),
5.21 (2H, d, J = 6.1 Hz, OCH2Ph), 4.31-4.15 (2H, 2 m, CHCH3), 1.52
(3H, dd, J = 6.6, 2.4 Hz CHCH3); 13C NMR (100 MHz, CDCl3) δ
172.6 (COOCH2Ph), 149.7 (Ph-C), 135.0 (Ph-C), 130.0, 128.7, 128.6,
128.4, 126.0, 120.6 (Ph-CH), 67.6 (OCH2Ph), 50.8 (CHCH3), 20.6
(CHCH3).
C28H35N6O9P: C 53.3, H 5.6, N 13.3 %.
Phenyl-(benzyloxy-L-alaninyl)
kinetin
riboside
phosphoramidate (13). Prepared as described for compound 11
using 2 (250 mg, 0.72 mmol), NMI (0.29 mL, 3.6 mmol) and 8
(765 mg, 2.16 mmol). The crude product was purified via flash
column chromatography was purified via flash column
chromatography to yield the final product as a white solid (60
mg, 13%); (Eluent 3:97 to 5:95 MeOH:CH2Cl2); 31P NMR (120
MHz, MeOD) δ 3.89, 3.64; 1H NMR (400 MHz, MeOD) δ 8.26
(1H, s, ArN-CH), 8.20, 8.17 (1H, 2 s, ArN-CH), 7.41 (1H, d, J = 1.8,
CH2ArO-H), 7.32-7.24 (7H, m, Ph-H), 7.21-7.06 (3H, m, Ph-H),
6.32 (1H, dd, J = 3.3, 1.9 Hz, CH2ArO-H), 6.29 (1H, d, J = 3.2 Hz,
CH2ArO-H), 6.03 (1H, t, J = 4.9 Hz, 1’-H), 5.18-4.98 (2H, 2 m,
CH2Ph), 4.77 (2H, br s, NHCH2), 4.67-4.57 (1H, m, 2’-H), 4.43-
4.33 (3H, m, 3’-H/4’-H/5’-H), 4.33-4.20 (1H, m, 5’-H), 4.02-3.85
(1H, m, CHCH3), 1.25 (3H, dd, J = 19.4, 7.0 Hz, CHCH3); 13C NMR
(100 MHz, MeOD) δ 174.8 (COOCH2Ph), 155.8 (ArN-C), 153.9
(ArN-CH), 152.0 (Ph-C), 150.2 (ArN-C), 143.3 (ArO-CH), 140.6
(ArN-CH), 139.0 (Ph-CH), 137.1 (Ph-C), 130.7, 129.2, 128.8, 126.2,
121.9, 121.3 (Ph-CH), 121.0 (ArN-C), 111.4, 108.2 (ArO-CH), 89.9 (1’-
CH), 84.3 (4’-C), 75.4 (2’-CH), 71.4 (3’-CH), 67.7 (CH2Ph), 67.1 (5’-
C), 51.5 (CHCH3), 38.2 (NHCH2), 20.4 (CHCH3); HRMS-ESI
(m/z): Calc. for C31H33N6O9NaP [M + Na]+ 687.1944, found
687.1942; Found: C 55.95, H 5.2, N 12.6. Calc. for C31H33N6O9P: C
56.0, H 5.0, N 12.65 %.
Phenyl-(isopropoxy-L-alaninyl)-phosphorochloridate (9).16
Prepared as described for compound 6 using L-alanine isopropyl
ester hydrochloride (700 mg, 4.18 mmol), phenyl
phosphorodichloridate (0.62 mL, 4.18 mmol) and Et3N (1.13 mL,
8.36 mmol). Product 9 was obtained as a yellow oil (1185 mg,
93%). 31P NMR (120 MHz, CDCl3) δ 8.10, 7.80; 1H NMR (400 MHz,
CDCl3) δ 7.46-7.32 (2H, m, Ar-H), 7.30-7.19 (3H, m, Ar-H), 5.16-
5.00 (1H, m, OCHiPr), 4.50-4.30 (1H, m, N-H), 4.22-4.03 (1H, m,
CHCH3), 1.52-1.47 (3H, m, CHCH3), 1.32-1.22 (6H, m, OCHiPr); 13
C
NMR (100 MHz, CDCl3) δ 172.2 (COCH3), 149.9 (Ar-COP), 130.0,
126.1, 120.7 (Ar-CH), 69.8 (OCHiPr), 50.8 (CHCH3), 21.8 (2C,
OCHiPr), 20.6 (CHCH3).
Phenyl-(methoxy-L-alaninyl)
phosphoramidate (11). KR
kinetin
(200 mg, 0.60 mmol) was
riboside
2
suspended in anhydrous THF (15 mL) under an inert
atmosphere. To this, tBuMgCl (0.09 mL, 0.68 mmol) was then
added dropwise over 15 min. The resulting solution was stirred
for 10 min and following this, 6 (241 mg, 0.86 mmol) in
anhydrous THF (1.5 mL) was then added dropwise over 10 min.
The mixture was left to stir for 18 h. MeOH (2 mL) was then
added to quench the reaction before solvent being removed
under reduced pressure to leave the crude product as a pale
yellow oil. This was purified via flash column chromatography
and then preparative TLC to yield the final product as a white
solid (34 mg, 10%); (Eluent 3:97 to 5:95 MeOH:CH2Cl2); δ 31P
NMR (120 MHz, MeOD) δ 3.84, 3.69; 1H NMR (400 MHz,
MeOD) δ 8.27 (1H, s, ArN-CH), 8.23, 8.20 (1H, 2 s, ArN-CH), 7.43
Phenyl-(isopropoxy-L-alaninyl)
kinetin
riboside
phosphoramidate (14). Prepared as described for compound 11
using 2 (250 mg, 0.72 mmol), NMI (0.29 mL, 3.60 mmol) and 9
(660 mg, 2.16 mmol). The crude product was purified via flash
column chromatography to yield the final product as a white
solid (185 mg, 42%); (Eluent 3:97 to 5:95 MeOH:CH2Cl2); 31P NMR
(120 MHz, CDCl3) δ 3.02, 2.86; 1H NMR (400 MHz, CDCl3) δ 8.27
(1H, s, ArN-CH), 7.98, 7.94 (1H, 2 s, ArN-CH), 7.30 (1H, dd, J =
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