4926
M. E. B. Smith et al. / Bioorg. Med. Chem. 18 (2010) 4917–4927
(138 mg, 0.292 mmol) and acetylene 25 (149 mg, 0.584 mmol) in a
mixture of degassed triethylamine (10 mL) and DMF (1 mL),
Pd(PPh3)4 (17 mg, 0.015 mmol) and copper(I) iodide (6 mg,
0.029 mmol) were added and the reaction stirred at for 17 h. The
mixture was concentrated to dryness in vacuo and the residue par-
titioned between ethyl acetate (50 mL) and water (50 mL). The or-
ganic phase was dried (MgSO4), concentrated under vacuum and
purified by silica flash chromatography (ethyl acetate/hexane,
1:2) to give 32 as a yellow oil (102 mg, 70%). dH (500 MHz; CDCl3)
7.31 (1H, dd, J 8.3 and 1.5, 5-ArH), 7.15 (1H, d, J 1.5, 3-ArH), 7.12
(1H, dd, J 8.2 and 2.0, 4-ArH(benzyl)), 6.99–7.01 (2H, m, 6-ArH
and 3-ArH(benzyl)), 6.87 (1H, d, J 1.7, 6-ArH(benzyl)), 4.74 (1H,
br s, NH), 4.09–4.12 (2H, m, CH2NH), 3.73 (2H, s, ArCH2Ar), 3.65
(2H, t, J 7.4, CH2Cl), 2.98 (2H, t, J 7.4, CH2Cl), 2.22 (3H, s, COCH3),
2.17 (3H, s, COCH3), 1.45 (9H, s, C(CH3)3); dC (125 MHz; CDCl3)
169.3, 169.0, 155.3, 149.0, 147.9, 136.2, 134.1, 131.8, 131.23,
131.20, 131.0, 128.3, 122.7, 122.6, 120.8, 85.6, 82.2, 80.1, 44.8,
38.6, 31.2, 30.6, 28.4, 20.8, 20.7; m/z (HRES) found [MNa]+
522.1670; C27H30ClNNaO6 requires 522.1659.
3.33. 4-(3-Acetamidopropyl)-2-(2-acetoxy-5-(2-chloroethyl)
benzyl)phenyl acetate 36
To diacetate 35 (20 mg, 0.040 mmol) in dichloromethane (4 mL)
at 0 °C TFA (1 mL) was added and the reaction was stirred at 0 °C
for 2 h. The mixture was evaporated to dryness in vacuo and the
residue in pyridine (3 mL) added to acetic anhydride (1 mL) and
DMAP (cat.). The reaction was stirred for 17 h, concentrated to dry-
ness and the residue partitioned between ethyl acetate (50 mL)
and 0.3 M potassium hydrogen sulfate (50 mL). The organic phase
was dried, concentrated under vacuum and purified by silica flash
chromatography (ethyl acetate) to give 36 as a colourless oil
(18 mg, 100%). dH (500 MHz; CDCl3) 7.12 (1H, dd, J 8.2 and 2.1, 4-
ArH(benzyl)), 7.05 (1H, dd, J 8.2 and 2.0, 5-ArH), 7.00 (1H, d, J
8.2, 3-ArH(benzyl)), 6.95 (1H, d, J 8.2, 6-ArH), 6.93 (1H, d, J 2.0,
6-ArH(benzyl)), 6.81 (1H, d, J 2.0, 3-ArH), 5.49 (1H, br s, NH),
3.75 (2H, s, ArCH2Ar), 3.66 (2H, t, J 7.3, CH2Cl), 3.19 (2H, apparent
q, J 6.8, CH2NH), 2.99 (2H, t, J 7.3, ClCH2CH2Ar), 2.55 (2H, t, J 7.5,
CH2Ar), 2.20 (3H, s, OCOCH3), 2.17 (3H, s, OCOCH3), 1.91 (3H, s,
NHCOCH3), 1.72–1.78 (2H, m, CH2CH2CH2); dC (125 MHz; CDCl3)
170.4, 169.6, 169.5, 147.9, 147.2, 139.4, 136.1, 131.6, 131.34,
131.29, 130.5, 128.1, 127.5, 122.6, 122.3, 44.9, 39.1, 38.5, 32.6,
30.8, 30.5, 23.3, 20.82, 20.80; m/z (HRES) found [MNa]+
468.1563; C24H28ClNO5 requires 468.1554.
3.31. 4-(3-Acetamidoprop-1-ynyl)-2-(2-acetoxy-5-(2-chloroethyl)-
benzyl)phenyl acetate 34
To diacetate 32 (20 mg, 0.040 mmol) in dichloromethane
(4 mL) at 0 °C was added TFA (1 mL) and the reaction was stirred
at 0 °C for 2 h. The mixture was evaporated to dryness in vacuo
and to the residue 33 in pyridine (3 mL), acetic anhydride
(1 mL) and DMAP (cat.) were added. The reaction was stirred
for 17 h, concentrated to dryness in vacuo and the residue parti-
tioned between ethyl acetate (50 mL) and 0.3 M potassium
hydrogen sulfate (50 mL). The organic phase was dried (MgSO4),
evaporated, and purified by silica flash chromatography (ethyl
acetate/hexane, 1:1) to give 34 as a colourless oil (10 mg, 57%).
dH (500 MHz; CDCl3) 7.29 (1H, dd, J 8.3 and 2.0, 5-ArH), 7.09–
7.12 (2H, m, 3-ArH and 4-ArH(benzyl)), 6.98–7.00 (2H, m, 6-
ArH and 3-ArH(benzyl)), 6.86 (1H, d, J 1.9, 6-ArH(benzyl)), 5.77
(1H, br s, NH), 4.20 (2H, d, J 4.7, CH2NH), 3.72 (2H, s, ArCH2Ar),
3.63 (2H, t, J 7.4, CH2Cl), 2.97 (2H, t, J 7.4, CH2Ar), 2.20 (3H, s,
OCOCH3), 2.16 (3H, s, OCOCH3), 1.99 (3H, s, NHCOCH3); dC
(125 MHz; CDCl3) 170.0, 169.4, 169.0, 149.1, 147.9, 136.2,
134.1, 131.9, 131.2, 131.14, 131.11, 128.3, 122.8, 122.6, 120.6,
84.9, 82.7, 44.8, 38.5, 30.5, 30.2, 23.0, 20.83, 20.76; m/z (HRES)
found [MNa]+ 464.1242; C24H24ClNNaO5 requires 464.1241.
3.34. 2-(2-Acetoxy-5-(2-chloroethyl)benzyl)-4-(3-(6-(5-
((3aS,4S,6aR)-2-oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl)
pentanamido)hexanamido)prop-1-ynyl)phenyl acetate 37
To diacetate 32 (50 mg, 0.100 mmol) in dichloromethane (4 mL)
at 0 °C, TFA (1 mL) was added and the reaction was stirred at 0 °C
for 2 h. The mixture was concentrated to dryness and the residue
33 added to dichloromethane (5 mL) and DMF (1 mL). The reaction
was cooled to 0 °C and triethylamine (100 lL), Biotin X-SE (50 mg,
0.110 mmol) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiim-
ide (EDC) (22 mg, 0.110 mmol) added. The reaction was stirred
for 17 h at rt, then diluted with dichloromethane (50 mL), washed
with 0.3 M potassium hydrogen sulfate (50 mL) and the aqueous
phase extracted with further dichloromethane (50 mL). The com-
bined organic extracts were dried (MgSO4), concentrated under
vacuum and purified using silica flash chromatography (ethyl ace-
tate/methanol, 9:1 then neat methanol) to give 37 as a white solid
(53 mg, 72%); dH (600 MHz; methanol-d4) 7.34 (1H, dd, J 8.3 and
2.0, 5-ArH), 7.21 (1H, dd, J 8.2 and 2.2, 4-ArH(benzyl)), 7.16 (1H,
d, J 2.0, 3-ArH), 7.07 (1H, d, J 8.3, 6ArH), 7.02–7.04 (2H, m, 3-ArH(-
benzyl) and 6-ArH(benzyl)), 4.48–4.50 (1H, m, biotin CH2CHNH),
4.31 (1H, dd, J 7.9 and 4.5, biotin CHCHNH), 4.14 (2H, s, CH2NH),
3.79 (2H, s, ArCH2Ar), 3.73 (2H, t, J 7.2, CH2Cl), 3.15–3.23 (3H, m,
CH2NHCO and biotin CHS), 3.02 (2H, t, J 7.1, CH2Ar), 2.93 (1H, dd,
J 12.8 and 5.0, biotin CH2S), 2.71 (1H, d, J 12.8, biotin CH2S),
2.17–2.25 (10H, m, 2 ꢁ CH2 and 2 ꢁ COCH3), 1.51–1.77 (8H, m,
4 ꢁ CH2), 1.34–1.47 (4H, m, 2 ꢁ CH2); dC (150 MHz; CDCl3) 174.6,
174.3, 169.6, 169.2, 164.7, 149.1, 147.9, 136.4, 133.5, 132.2,
131.1, 130.9, 130.5, 128.0, 122.6, 122.4, 85.0, 81.1, 62.0, 60.2,
55.6, 44.4, 39.7, 38.8, 38.0, 35.4, 35.3, 30.2, 28.73, 28.70, 28.4,
28.1, 26.1, 25.5, 25.1, 19.31, 19.25; m/z (HRES) found [MNa]+
761.2745; C38H47ClN4NaO7S requires 761.2752.
3.32. 2-(2-Acetoxy-5-(2-chloroethyl)benzyl)-4-(3-(tert-butoxy-
carbonylamino)propyl)phenyl acetate 35
To diacetate 32 (89 mg, 0.178 mmol) in methanol (5 mL), pal-
ladium on carbon (20 mg; 10% wt, dry form) was added. The mix-
ture was stirred under a hydrogen atmosphere for 3 d. The
catalyst was removed by filtration and the solution concentrated
to dryness to give the desired compound as a colourless oil
(89 mg, 100%). dH (500 MHz; CDCl3) 7.10 (1H, dd, J 8.2 and 2.2,
4-ArH(benzyl)), 7.06 (1H, dd, J 8.2 and 2.1, 5-ArH), 6.99 (1H, d, J
8.2, 3-ArH(benzyl)), 6.95 (1H, d, J 8.2, 6-ArH), 6.89 (1H, d, J 2.0,
6-ArH(benzyl)), 6.84 (1H, d, J 2.0, 3-ArH), 4.55 (1H, br s, NH),
3.74 (2H, s, ArCH2Ar), 3.65 (2H, t, J 7.4, CH2Cl), 3.06–3.12 (2H,
m, CH2NH), 2.98 (2H, t, J 7.4, ClCH2CH2Ar), 2.55 (2H, t, J 7.6,
CH2Ar), 2.19 (3H, s, COCH3), 2.17 (3H, s, COCH3), 1.71–1.77 (2H,
m, CH2CH2CH2), 1.43 (9H, s, C(CH3)3); dC (125 MHz; CDCl3)
169.5, 169.4, 156.0, 147.9, 147.2, 139.6, 136.1, 131.7, 131.1,
130.6, 128.7, 128.1, 127.6, 122.5, 122.3, 79.2, 44.9, 38.6, 32.5,
31.6, 30.6, 30.1, 28.5, 20.8; m/z (HRES) found [MNa]+ 526.1976;
3.35. 4-(6-(3-(4-Acetoxy-3-(2-acetoxy-5-(2-chloroethyl)benzyl)
phenyl)prop-2-ynylamino)-6-oxohexylcarbamoyl)-2-(2,7-
difluoro-6-hydroxy-3-oxo-3H-xanthen-9-yl)benzoic acid 38
To diacetate 32 (8.0 mg, 0.016 mmol) in dichloromethane (4 mL)
at 0 °C, TFA (1 mL) was added and the mixture stirred at 0 °C for 2 h.
The mixture was concentrated to dryness and the residue 33 added
C27H34ClNNaO6 requires 526.1972.
to anhydrous dichloromethane (5 mL). Triethylamine (100 lL) and