Beilstein J. Org. Chem. 2013, 9, 89–96.
90:10:1). Product fractions were pooled and concentrated to δ 6.38 (br s, 1H), 5.60 (br s, 1H), 5.36 (br s, 1H), 5.29 (br s,
leave 324 mg (76%) of 8 as a pale white solid: 1H NMR (500 1H), 4.51 (m, 1H), 4.40–4.21 (m, 5H), 3.90–3.55 (m,12H),
MHz, CDCl3) δ 6.66 (br s, 1H), 6.61 (br s, 1H), 6.03 (br s, 1H), 3.30–3.11 (m, 5H), 2.92 (dd, J = 4.9, 12.9 Hz, 1H), 2.74 (d, J =
5.42 (br s, 1H), 4.46 (t, J = 6 Hz, 1H), 4.26 (t, J = 6 Hz, 1H), 12.9 Hz, 1H), 2.35–2.18 (m, 4H), 1.85–1.40 (m, 12H); 1.31 (t, J
4.14–4.12 (m, 2H), 4.06–4.02 (m, 4H), 3.64–3.58 (m, 12H), = 6.0 Hz, 3H); 13C NMR (125 MHz, CDCl3) δ 173.3, 163.9,
3.15–3.06 (m, 7H), 2.84 (dd, J = 5 Hz, 13 Hz, 1H), 2.69 (d, J = 156.6, 70.5, 70.4, 69.6, 64.2, 63.7, 63.6, 63.5, 61.8, 60.2 55.7,
13 Hz, 1H), 2.13 (t, J = 7.3 Hz, 2H), 2.10–2.05 (m, 2H), 40.6, 39.2, 35.8, 29.5, 28.9, 28.1, 28.0, 26.8, 25.7, 24.9, 23.8,
1.63–1.59 (m, 4H), 1.45–1.37 (m, 6H), 1.29–1.25 (m, 6H); 16.4, 16.3; 19F NMR (282 MHz, CDCl3) δ −59.4, −63.2;
13C NMR (125 MHz, CDCl3) δ 173.4, 164.2, 156.6, 70.5, 70.4, 31P NMR (121 MHz, CDCl3) δ 32.8, 24.0; MS m/z: 643.2
70.1, 69.6, 65.0, 63.7, 61.8, 61.7, 61.6, 60.2, 55.7, 40.6, 40.5, [M + H]+.
39.2, 35.8, 29.5, 28.9, 28.2, 28.0, 27.4, 26.3, 25.7, 23.9, 16.4,
16.3; MS m/z: 669.2 [M + H]+.
tert-Butyl (5-(5-((3aS,4S,6aR)-2-oxohexahydro-1H-
thieno[3,4-d]imidazol-4-yl)pentanamido)pentyl)carbamate
2-(2-(2-(2-(Ethoxy(hydroxy)phosphoryl)ethoxy)ethoxy)eth- (11): This compound was made by the procedure of Konoki et
oxy)ethyl (5-(5-((3aS,4S,6aR)-2-oxohexahydro-1H- al. [18] from tert-butyl (5-aminopentyl)carbamate (10; made by
thieno[3,4-d]imidazol-4-yl)pentanamido)pentyl)carbamate the procedure of Kaur et al. [25]) and D-biotin. The 1H NMR
(9): A mixture of lithium azide (200 mg, 4.1 mmol), diethyl spectrum is the same as previously reported [18]; 13C NMR
phosphonate polyether carbamate 8 (150 mg, 0.22 mmol), and (125 MHz, CDCl3) δ 173.3, 164.2, 156.2, 79.1, 61.8, 60.2, 55.8,
2 mL of DMF was stirred at 95 °C for 18 h. DMF was removed 40.5, 40.3, 39.2, 36.0, 29.7, 29.1, 28.4, 28.2, 28.0, 25.8, 23.9;
under vacuum to leave a yellow oil, which was diluted with MS m/z: 451.1 [M + Na]+.
water and loaded onto a column of Amberlite–IR120 (H+) resin.
The column was eluted with DI water and the collected eluate N-(5-Aminopentyl)-5-((3aS,4S,6aR)-2-oxohexahydro-1H-
was evacuated at 30 mm/Hg with stirring for 30 min at rt (to thieno[3,4-d]imidazol-4-yl)pentanamide (12): This com-
draw off hydrazoic acid) and then lyophilized to leave a crude pound was made similar to the procedure of Konoki et al. [18].
yellow residue, which was purified by flash chromatography. To an ice-cold solution of tert-butyl 5-(biotinamido-
Gradient elution with dichloromethane/methanol/NH4OH pentyl)carbamate (11; 136 mg, 0.32 mmol) in dichloromethane
(70:30:2 and then 80:20:1) followed by pooling and concentra- (2.0 mL) was added dropwise trifluoroacetic acid (1.0 mL). The
tion of product fractions left 0.125 g (87%) of 9 as a colorless cooling bath was removed and the mixture was stirred for 2 h.
solid: 1H NMR (500 MHz, CD3OD) δ 4.53–4.50 (m, 1H), The solution was concentrated in vacuo to a yellow oil, which
4.34–4.31 (m, 1H), 4.18 (t, J = 4.6 Hz, 2H), 3.95–3.89 (m, 2H), was used in the next step without further purification: 1H NMR
3.76–3.62 (m, 12H), 3.28–3.18 (m, 3H), 3.12 (t, J = 7 Hz, 2H), (300 MHz, CD3OD) δ 4.45 (dd, J = 8.0, 5.5 Hz, 1H), 4.26 (dd, J
2.95 (dd, J = 4.9 Hz, 12.9 Hz, 1H), 2.73 (d, J = 12.9 Hz, 1H), = 7.5, 4.5 Hz, 1H), 3.15–3.11 (m, 3H), 2.90–2.85 (m, 1H),
2.22 (t, J = 7.3 Hz, 2H), 1.97–1.91 (m, 2H), 1.80–1.37 (m, 2.67–2.61 (m, 3H), 2.16 (t, J = 7.5 Hz, 2H), 1.71–1.48 (m, 4H),
12H), 1.26 (t, J = 7 Hz, 3H); 13C NMR (125 MHz, CD3OD) δ 1.42–1.33 (m, 8H); MS m/z: 329.1 [M + H]+.
174.5, 164.7, 157.3, 69.8, 69.7, 69.5, 69.2, 66.7, 63.4, 62.0,
60.2, 59.6, 55.6, 40.3, 39.7, 38.9, 35.5, 29.2, 28.7, 28.4, 28.1,
Supporting Information
28.0, 25.6, 23.8, 15.9, 15.8; MS m/z: 641.2 [M + H]+.
Supporting Information File 1
Biology experimental details and digital NMR spectra for
synthesized compounds.
2-(2-(2-(2-(Ethoxy(fluoro)phosphoryl)ethoxy)ethoxy)eth-
oxy)ethyl (5-(5-((3aS,4S,6aR)-2-oxohexahydro-1H-
thieno[3,4-d]imidazol-4-yl)pentanamido)pentyl)carbamate
(FP–PEG–biotin; 1): To a solution of monoethyl phosphonate
polyether carbamate 9 (46 mg, 0.072 mmol) in 1 mL of anhy-
drous dichloromethane at −42 °C was added (diethyl-
amino)sulfur trifluoride (DAST; 26.4 μL, 0.022 mmol). The
mixture was stirred for 30 min and quenched with water at
−42 °C. After stirring at room temperature for 10 min, the mix-
ture was extracted with dichloromethane (3×). The organic
phase was dried and concentrated to a yellow oil that was evac-
uated under high vacuum to leave 37 mg (80%) of 1, which was
used directly in biological studies: 1H NMR (500 MHz, CDCl3)
Acknowledgements
The authors thank members of the Vahlteich Medicinal Chem-
istry Core for helpful synthetic suggestions, Dr. Chester
Provoda for his biology suggestions, and Kefeng Sun and
Yasuhiro Tsume for their help with biology experiments. Finan-
cial support to HX from the National Institutes of Health (GM
037188) is gratefully acknowledged.
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