156
A. Scaffidi et al. / Tetrahedron 67 (2011) 152e157
was added, methanesulfonyl chloride (32 mg, 0.3 mmol) in
dichloromethane (0.5 mL) and the solution left to stand (30 min).
The reaction was subjected to a usual workup (dichloromethane) to
leave a white powder that was dissolved in dimethylformamide
(2.0 mL) followed by the addition of sodium azide (70 mg,
1.1 mmol). The mixture was stirred at room temperature (30 min)
before being subjected to a usual workup (dichloromethane) and
flash chromatography (ethyl acetateehexane 3:7) to return the
azide 8 (26 mg, 81%) as a tan powder. Rf (ethyl acetateehexane 1:1)
0.8; mp 118e120 ꢁC; dH (600 MHz) 7.41 (1H, s, H7), 6.52 (1H, s, H4),
4.17 (2H, s, H8), 1.95 (3H, s, H3b). dC (150.9 MHz) 171.03 (C2), 154.66
(C5), 141.69, 139.76 (C3a, C7a), 126.10 (C7), 101.80 (C3), 101.35 (C4),
51.39 (C8), 7.71 (C3b); HRMS (EI): m/z found 205.0488. C9H7N3O3
requires 205.0487.
108e110 ꢁC; dH (500 MHz, CD3OD) 7.83 (1H, s, H70/H4), 7.78 (1H, s,
H4/H70), 6.88 (1H, s, H40), 4.48 (1H dd, J3a ,6a ¼7.9 Hz, J6 ,6a ¼5.0 Hz,
00
00
00
00
H6a00), 4.41 (2H, s, H80/H6), 4.32 (2H, s, H6/H80), 4.37 (2H, t,
0
00
0
0
00 00
J17 ,18 ¼7.1 Hz, H18 ), 4.28 (1H, dd, J3a ,4 ¼4.4 Hz,00H3a ), 3.55 (2H, t,
0
0
0
J10 ,11 ¼6.5 Hz, H10 ), 3.20e3.15 (1H, m, H4 ), 2.91 (1H, dd,
00
00
00 00
00
00
J6 ,6 ¼12.7 Hz, H6 ), 2.70 (1H, d, H6 ), 2.23 (1H, t, J9 ,10 ¼7.3 Hz,
H1000), 1.90 (3H, s, H3b0), 1.90e1.85, 1.75e1.53, 1.45e1.25 (20H, 3m,
H110, H120, H130, H140, H150, H160, H170, H700, H800, H900). dC
(150.9 MHz) 175.95, 173.65, 166.09 (C20, C1100, C1200), 160.10 (C50),
146.28 (C5), 143.16, 142.79 (C3a0, C7a0), 128.99 (C70), 124.14 (C4),
101.92 (C40), 100.52 (C30)72.39, 69.84 (C80, C100), 63.33 (C3a00), 61.63
(C6a00), 56.99 (C400), 51.34 (C180), 41.05 (C600), 36.55, 35.60, 31.27,
30.64, 30.46, 30.32, 29.99, 29.70, 29.44, 27.42, 27.09, 26.70 (C6, C110,
C120, C130, C140, C150, C160, C170, C700, C800, C900, C1000), 7.44 (C3b0).
HRMS (EI): m/z found 628.3049. C31H44N6O6S requires 628.3043.
4.3.2. 5-(2-(2-(2-Azidoethoxy)ethoxy)ethoxy)methyl-3-methyl-2H-
furo[2,3-c]pyran-2-one (10). Sodium hydride (60% dispersion in
mineral oil, 30 mg, 0.8 mmol) was added to a stirred solution of 1-
(2-azidoethoxy)-2-(2-bromoethoxy)ethane 934 (500 mg, 2.1 mmol)
and the alcohol 715 (75 mg, 0.4 mmol) in dimethylformamide
(2.0 mL) at 0 ꢁC and the solution stirred (10 min). The reaction was
allowed to warm to room temperature (3 h) before being quenched
with methanol (0.5 mL). A usual workup (dichloromethane) fol-
lowed by flash chromatography (ethyl acetateetoluene 3:7) and
semi-preparative HPLC (C18, acetonitrile-water 9:11) yielded the
azide 10 (10 mg, 7%) as a colourless glass. Rf (ethyl aceta-
teedichloromethane 1:9) 0.6; dH (500 MHz) 7.43 (1H, s, H7), 6.62
(1H, s, H4), 4.37 (2H, s, H8), 3.76e3.67 (10H, m, H10, H11, H13, H14,
H16), 3.40 (2H, t, J16,17¼5.2 Hz, H17), 1.62 (3H, s, H3b). dC
(125.7 MHz) 171.46 (C2), 157.40 (C5), 141.82, 140.61 (C3a, C7a),
126.22 (C7), 100.57 (C4), 100.42 (C3), 70.74, 70.71, 70.66, 70.08,
69.29 (C10, C11, C13, C14, C16, C17) 50.67 (C8), 7.71 (C3b); HRMS
(EI): m/z found 337.1274. C15H19N3O6 requires 337.1274.
4.3.5. 5-(3-Azido-5-(azidomethyl)benzyloxy)methyl-3-methyl-2H-
furo[2,3-c]pyran-2-one (17). Sodium hydride (60% dispersion in
mineral oil, 55 mg, 1.4 mmol) was added to a stirred solution of the
bromide 1635 (300 mg, 1.1 mmol) and alcohol 715 (190 mg,
1.1 mmol) in dimethylformamide (5.0 mL) at 0 ꢁC and the solution
stirred (2 h). The reaction was quenched with methanol (1.0 mL)
followed by a usual workup (ethyl acetate) and flash chromatog-
raphy (ethyl acetateehexane 1:3) yielded the azide 17 (92 mg, 24%)
as a light yellow powder. Rf (ethyl acetateehexane 1:2) 0.3; mp
60e63 ꢁC; dH (600 MHz) 7.42 (1H, s, H7), 7.08, 7.02, 6.94 (3H, 3s,
H12, H14, H16), 6.58 (1H, s, H4), 4.63 (2H, s, H10), 4.36, 4.33 (4H, 2s,
H8, H17), 1.98 (3H, s, H3b). dC (150.9 MHz) 171.26 (C2), 156.66 (C5),
141.74, 141.08, 140.24, 139.71, 137.80 (C3a, C7a, C11, C13, C15), 126.11
(C7), 123.35, 118.12, 117.70 (C12, C14, C16), 100.86 (C4), 100.79 (C3),
72.27, 68.36 (C8, C10), 54.05 (C17), 7.64 (C3b); HRMS (EI): m/z found
366.1084. C17H14N6O4 requires 366.1077.
4.3.6. 3a,4,5,7,7a-[13C]5-3-Methyl-2H-furo[2,3-c]pyran-2-one
(19). Compound 19 was prepared in a manner previously described
for the preparation of karrikinolide 1 with the exception that 13C5-
4.3.3. 5-(9-Azidononoxy)methyl-3-methyl-2H-furo[2,3-c]pyran-2-
one (12). Sodium hydride (60% dispersion in mineral oil, 90 mg,
2.2 mmol) was added to a stirred solution of 1-azido-9-bromono-
nane 11 (850 mg, 3.4 mmol) and the alcohol 715 (210 mg, 1.2 mmol)
in dimethylformamide (5.0 mL) at 0 ꢁC and the solution stirred
(10 min). The reaction was allowed to warm to room temperature
(3 h) before being quenched with methanol (1.0 mL). A usual
workup (dichloromethane) followed by flash chromatography
(ethyl acetateedichloromethane 3:97) afforded the azide 12
(60 mg, 15%) as a light yellow powder. Rf (ethyl acetateehexanes
1:1) 0.6; mp 28e30 ꢁC; dH (600 MHz) 7.41 (1H, s, H7), 6.55 (1H, s,
H4), 4.26 (2H, s, H8), 3.55 (2H, t, J10,11¼6.6 Hz, H10), 3.25 (2H, t,
J17,18¼7.0 Hz, H18), 1.92 (3H, s, H3b), 1.65e1.55, 1.40e1.30 (14H, 2m,
H11, H12, H13, H14, H15, H16, H17). dC (150.9 MHz) 171.37 (C2),
157.65 (C5), 141.72, 140.54 (C3a, C7a), 126.12 (C7), 100.25 (C4),
100.23 (C3), 71.76, 68.79 (C8, C10), 51.34 (C18), 29.44, 29.26, 29.17,
28.96, 28.70, 26.57, 25.89 (C11, C12, C13, C14, C15, C16, C17), 7.61
(C3b); HRMS (EI): m/z found 347.1853. C18H25N3O4 requires
347.1845.
D
-xylose 18 was used as the starting material.15 Rf (ethyl aceta-
teehexane 1:2) 0.3; mp 118e120 ꢁC; da (600 MHz) 7.61e7.59,
H
7.28e7.25 (1H, 2m, H7), 7.51e7.46, 7.18e7.13 (1H, 2m, H5),
6.68e6.63, 6.39e6.35 (1H, 2m, H4), 1.93 (3H, d, JH3b,C3a¼4.7, H3b).
db (150.9 MHz) 171.13 (m, C2), 147.86 (dddd, J4,5¼71.5 Hz, C5),
C
142.16 (dddd, J7,7a¼97.0 Hz, J3a,7a¼46.6 Hz, H7a), 139.60 (dddd,
J3a,4¼57.3 Hz, H3a), 126.68 (br d, H7), 103.31 (dddd, C4), 100.19 (m,
C3), 7.56 (C3b). HRMS (EI): m/z found 155.0489. 12C133C5H6O3 re-
a
quires 155.0485. Multiplets split by 13C coupling. bOnly one bond
coupling assigned.
4.3.7. 7-[3H]-3-Methyl-2H-furo[2,3-c]pyran-2-one (20). Lithium bis
(trimethylsilyl)amide (1 M solution in tetrahydrofuran, 2.0 mL,
2.0 mmol) was added to karrikinolide 1 (150 mg, 1.0 mmol) in
tetrahydrofuran (10 mL) at ꢀ78 ꢁC and the resulting brown solution
stirred (15 min). [3H]eWater (5.0 mCi/mL, 50
mL, 2.5 mmol) was
added to the solution and the resulting mixture allowed to warm to
room temperature (1 h). The reaction was subjected to flash chro-
matography (ethyl acetateehexane 1:3) to return an orange pow-
der. This powder was treated with activated charcoal, filtered and
concentrated. Recrystallisation from hexane returned the radio-
labelled karrikinolide 20 (40 mg, 27%) as light yellow cyrstals.
Specific activity 85 mCi/mol.
4.3.4. N-(1-(9-((3-Methyl-2-oxo-2H-furo[2,3-c]pyran-5-yl)methoxy)
nonyl-1H-1,2,3-triazol-4-yl)methyl)-5-[(3aS,4S,6aR)-2-oxohexahy-
dro-1H-thieno[3,4-d]imidazol-4-yl]pentanamide (14). Copper (II)
sulfate pentahydrate (0.1 M solution, 50
sodium ascorbate (0.1 M solution, 200
(18 mg, 52
m
L, 5.0
m
m
mol) was added to
mol), the azide 12
mol) and biotin alkyne 1327 (15 mg, 53
m mmol) in
mL, 20
a mixture of ethanol and water (1:1, 4.0 mL) and the reaction
allowed to stand overnight at room temperature. The reaction was
concentrated followed by flash chromatography (meth-
anoledichloromethane 1:19e1:9) and semi-preparative HPLC (C18,
acetonitrileewater 1:1) to furnish the triazole 14 (17 mg, 52%) as
a white powder. Rf (methanoledichloromethane 3:17) 0.4; mp
Acknowledgements
This work was supported by the Australian Research Council
(grant nos. LP0882775, FF0457721, DP0667197, DP0880484) and
the Centres of Excellence Program of the Government of Western
Australia.