L. Herrera et al. / Carbohydrate Research 338 (2003) 293–298
297
3
1.44, 1.32 (2s, 2×3H, CMe2); 0.82 (s, 9H, CMe3); 0.08,
0.04 (2s, 2×3H, SiMe2); 13C NMR (62.9 MHz,
CDCl3): l 146.3 (C-7a); 134.2 (C-3); 117.9 (C-3a); 109.4
(CMe2); 78.6 (C-5); 70.1 (C-6); 69.6 (C-4); 36.4 (NMe);
29.0 (C-7); 28.2, 26.3 (CMe2); 25.7 (CMe3); 19.2 (SMe);
18.0 (CMe3); −4.7, −4.8 (SiMe2); MS, CI (m/z): 385
[M+1]+; Anal. Calcd for C18H32N2O3SSi: C 56.21; H
8.39; N 7.28; S 8.34. Found: C 56.08; H 8.52; N 7.12; S
8.22.
3J6,7ꢀ4.0 Hz, J7,8ꢀ2.8 Hz, H-7); 3.11 (dd, 1H,
3
2J8,8%ꢀ16.5 Hz, J7,8ꢀ2.8 Hz, H-8); 2.84 (ddd, 1H,
3
4
2J8,8%ꢀ16.5 Hz, J7,8%ꢀ4.8 Hz, J6,8%ꢀ1.5 Hz, H-8%);
4
1.42 (t, 3H, JMe,Meꢀ0.6 Hz, CMe2); 1.27 (t, 3H,
4JMe,Meꢀ0.6 Hz, CMe2); 0.73 (s, 9H, CMe3); 0.1, 0.06
(2s, 2×3H, SiMe2); 13C NMR (75.5 MHz, acetone-D6):
l 164.6 (C-8a); 158.8 (C-2); 157.4 (C-4); 129.0 (C-4a);
110.0 (CMe2); 77.8 (C-6); 72.7 (C-5); 70.1 (C-7); 36.6
(C-8); 27.3 (1×CMe2); 25.9 (CMe3); 25.0 (1×CMe2);
18.4 (CMe3); −4.8 (2×SiMe2); MS, CI (m/z): 337
[M+1]+; Anal. Calcd for C17H28N2O3Si: C 60.68; H
8.39; N 8.32. Found: C 60.54; H 8.58; N 8.23.
1.7. (4R,5R,6R)-6-[(tert-Butyl-dimethylsilyl)oxy]-
4,5,6,7-tetrahydro-4,5-(isopropylidenedioxy)-2-methyl-
2H-benzo[c]pyrazole (7)
1.9. (5R,6R,7R)-7-[(tert-Butyl-dimethylsilyl)oxy]-
5,6,7,8-tetrahydro-5,6-(isopropylidenedioxy)-2-
methyl-benzo[d]pyrimidine (9)
A mixture of 4 (0.355 g, 1.0 mmol) and methylhy-
drazine (0.16 mL, 3.0 mmol) was reacted as described
for preparation of 5. The residue was purified by
column chromatography (toluene/ethyl acetate 2:1) to
yield 0.23 g (69%) of 7 as colourless solid; TLC: tolu-
ene/ethyl acetate 2:1 Rf: 0.27; mp 81–83 °C; [h]2D1:
Compound 4 (53 mg, 0.15 mmol) and acetamidinium
hydrochloride (28 mg, 0.3 mmol) was reacted as de-
scribed for preparation of 8. The residue was purified
by column chromatography (toluene/ethyl acetate 1:1)
to yield 17 mg (33%) of 9 as colourless solid; TLC:
toluene/ethyl acetate 1:1 Rf: 0.44; mp 60–62 °C; [h]2D1:
1
+18.6 (c 1.0, CHCl3); IR (KBr): 1564 cm−1 (CꢁC); H
NMR (300.1 MHz, CDCl3): l 7.35 (s, 1H, H-3); 5.18
3
(d, 1H, J4,5ꢀ5.5 Hz, H-4); 4.20–4.12 (m, 2H, H-5,
2
1
H-6); 3.84 (s, 3H, NMe); 2.93 (dd, 1H, J7,7%ꢀ16.0 Hz,
+33.5 (c 1.0, CHCl3); H NMR (300.1 MHz, acetone-
2
3J6,7ꢀ3.8 Hz, H-7); 2.58 (dd, 1H, J7,7%ꢀ16.0 Hz,
3
D6): l 8.51 (s, 1H, H-4); 5.31 (d, 1H, J5,6ꢀ6.5 Hz,
3J6,7%ꢀ7.5 Hz, H-7%); 1.41, 1.36 (2s, 2×3H, CMe2);
0.85 (s, 9H, CMe3); 0.09, 0.06 (2s, 2×3H, SiMe2); 13C
NMR (62.9 MHz, CDCl3): l 146.9 (C-7a); 129.3 (C-3);
113.7 (C-3a); 109.4 (CMe2); 79.3 (C-5); 70.5 (C-6); 69.3
(C-4); 38.9 (NMe); 29.2 (C-7); 28.2, 26.1 (CMe2); 25.7
(CMe3); 18.0 (CMe3); −4.6, −4.7 (SiMe2); MS, CI
(m/z): 339 [M+1]+; Anal. Calcd for C17H30N2O3Si: C
60.32; H 8.93; N 8.28. Found: C 60.18; H 8.82; N 8.12.
3
3
H-5); 4.40 (ddd, 1H, J5,6ꢀ6.5 Hz, J6,7ꢀ4.1 Hz,
4J6,8%ꢀ1.3 Hz, H-6); 4.34 (ddd, 1H, J7,8%ꢀ5.0 Hz,
3
3J6,7ꢀ4.1 Hz, J7,8ꢀ3.0 Hz, H-7); 3.05 (dd, 1H,
3
2J8,8%ꢀ16.4 Hz, J7,8ꢀ3.0 Hz, H-8); 2.77 (ddd, 1H,
3
2J8,8%ꢀ16.4 Hz, J7,8%ꢀ5.0 Hz, J6,8%ꢀ1.3 Hz, H-8%);
3
4
4
2.57 (s, 3H, 2-Me); 1.40 (t, 3H, JMe,Meꢀ0.6 Hz,
CMe2); 1.27 (t, 3H, JMe,Meꢀ0.6 Hz, CMe2); 0.74 (s,
4
9H, CMe3); 0.1, 0.06 (2s, 2×3H, SiMe2); 13C NMR
(75.5 MHz, acetone-D6): l 168.0 (C-2); 164.5 (C-8a);
157.6 (C-4); 125.5 (C-4a); 109.8 (CMe2); 78.0 (C-6);
72.6 (C-5); 70.2 (C-7); 36.8 (C-8); 27.3 (1×CMe2); 25.9
(CMe3); 25.8 (2-Me); 25.1 (1×CMe2); 18.4 (CMe3);
−4.7, −4.8 (SiMe2); MS, CI (m/z): 351 [M+1]+;
Anal. Calcd for C18H30N2O3Si: C 61.68; H 8.63; N 7.99.
Found: C 61.49; H 8.54; N 7.75.
1.8. (5R,6R,7R)-7-[(tert-Butyl-dimethylsilyl)oxy]-
5,6,7,8-tetrahydro-5,6-(isopropylidenedioxy)-benzo[d]-
pyrimidine (8)
To a solution of sodium (7 mg, 0.3 mmol) in methanol
(2 mL) was added formamidinium acetate (31 mg, 0.3
mmol). After stirring for 20 min. at 22 °C this mixture
was dropwise added to another stirred solution of 4 (53
mg, 0.15 mmol) in methanol (2 mL). The resulting
mixture was stirred at 50 °C for 1.5 h (TLC control).
The mixture was cooled to 20 °C, and a saturated
solution of NH4Cl (10 mL) was added. The mixture
was extracted three times with CHCl3 (25 mL). The
combined organic layers were washed with water, dried
(Na2SO4) and concentrated. The residue was purified
by column chromatography (toluene/ethyl acetate 2:1)
to yield 15 mg (30%) of 8 as colourless syrup; TLC:
toluene/ethyl acetate 2:1 Rf: 0.38; [h]2D1: +20.5 (c 1.0,
1.10. (5R,6R,7R)-7-[(tert-Butyl-dimethylsilyl)oxy]-
5,6,7,8-tetrahydro-5,6-(isopropylidenedioxy)-2-phenyl-
benzo[d]pyrimidine (10)
Compound 4 (53 mg, 0.15 mmol) and benzamidinium
hydrochloride (47 mg, 0.3 mmol) was reacted as de-
scribed for preparation of 8. The residue was purified
by column chromatography (toluene/ethyl acetate 10:1)
to yield 30 mg (49%) of 10 as colourless solid; TLC:
toluene/ethyl acetate 10:1 Rf: 0.48; mp 67–69 °C; [h]2D1:
1
+57.9 (c 1.0, CHCl3); H NMR (300.1 MHz, acetone-
1
CHCl3); H NMR (300.1 MHz, acetone-D6): l 8.97 (s,
D6): l 8.74 (s, 1H, H-4); 8.49 (m, 2H, o-Ph); 7.50 (m,
3
3
1H, H-2); 8.64 (s, 1H, H-4); 5.36 (d, 1H, J5,6ꢀ6.5 Hz,
3H, m-, p-Ph); 5.40 (d, 1H, J5,6ꢀ6.5 Hz, H-5); 4.50–
3
3
2
H-5); 4.44 (ddd, 1H, J5,6ꢀ6.5 Hz, J6,7ꢀ4.0 Hz,
4.40 (m, 2H, H-6, H-7); 3.20 (dd, 1H, J8,8%ꢀ16.3 Hz,
4J6,8%ꢀ1.5 Hz, H-6); 4.39 (ddd, 1H, J7,8%ꢀ4.8 Hz,
3J7,8ꢀ2.8 Hz, H-8); 2.94 (ddd, 1H, J8,8%ꢀ16.3 Hz,
3
2