635
4.1.14.5. 1,3-di-[N-benzyl-N-[(benzyloxy)carbonyl)]-1-
phenylsulfenyl-propanone 8e
N); 4.2 (d, J = 8.7 Hz, 1H, N-CH(H)-CO); 4.7 (s, 1H,
CH-SPh); 6.7 (d, J = 11.6 Hz, 4H, ar), 6.8–7.0 (m, 10H,
ar); 7.1–7.2 (m, 5H, ar); 7.4 (d, J = 11.6 Hz, 4H, ar); MS
(NOBA) m/z 703 MH+. Anal. C41H44N4O5S (C, H, N, O).
Compound 8e was prepared from 7e (0.25 g,
0.47 mmol) according to general procedure B and ob-
tained as an oil (0.12 g, 40%). Rf = 0.13 (hexane/EtOAc
1
8:2). H NMR (CDCl3) δ 3.6 (d, J = 11.6 Hz, 2H,
4.1.15. 1,3-Bis[N-[N-[(tert-butyloxy)carbonyl]valinyl]
amino]-1-phenylsulfenyl-propanone 8j
PhCH(H)-N); 3.8 (d, J = 11.6 Hz, 2H, PhCH(H)-N); 4.2
(d, J = 9.0 Hz, 2H, N-CH(H)-CO); 4.3 (d, J = 9.0 Hz, 1H,
N-CH(H)-CO); 4.5 (s, 4H, PhCH2-O), 5.1 (s, 1H, CH-
PhS); 7.1–7.3 (m, 25H, ar). MS (FAB) m/z 645 MH+.
Anal. C39H36N2O5S (C, H, N, O).
A solution of 7j (1 g, 2.06 mmol) and PhSO2-SPh
(1.13 g, 0.54 mmol) in dry dichloroethane (10 mL) was
treated with a solution of n-BuLi 1.6 M in hexane
(1.4 mL, 2.26 mmol) under N2 atmosphere at –25 °C.
After 30 min of stirring, NaH (90 mg, 2.26 mmol) was
added. The reaction mixture was allowed to warm to
room temperature while stirring for 3 h. The resulting
solution was diluted with CH2Cl2 (10 mL) and washed
with two portions of 5% aqueous citric acid (10 mL), then
saturated brine (10 mL), dried over Na2SO4 and evapo-
rated in vacuo. The residue was purified by silica gel
chromatography using hexane/EtOAc (7:3) to give 8j
4.1.14.6.
1,3-di-[N-benzyl-N-[[(N-methyl-N-phenyl)
amino]carbonyl]amino]-1-phenylsulfenyl-propanone 8f
Compound 8f was prepared from 7f (0.4 g; 0.75 mmol)
according to general procedure B and obtained as an oil
1
(0.22 g, 45%). Rf = 0.35 (hexane/EtOAc 6.5:3.5). H
NMR (CDCl3) δ 2.9 (s, 3H, CH3N); 3.0 (s, 3H, CH3N);
3.7 (d, J = 8.7 Hz, 1H, N-CH(H)-CO); 4.0 (d, J = 8.7 Hz,
1H, N-CH(H)-CO); 4.2 (d, J = 9.5 Hz, 4H, PhCH2-N);
5.2 (s, 1H, CH-PhS); 6.7–7.2 (m, 25H, ar). MS (NOBA)
m/z 643 MH+. Anal. C39H38N4O3S (C, H, N, O).
1
(0.44 g, 35%). Rf = 0.17 (hexane/EtOAc 7:3). H NMR
(CDCl3) δ 0.7 (d, J = 6.5 Hz, 6H, (CH3)2CH); 0.7 (d, J
= 6.5 Hz, 6H, (CH3)2CH); 1.31 (s, 9H, t-Bu); 1.33 (s, 9H,
t-Bu); 1.8 (m, 2H, CH(CH3)2); 3.8 (br, 3H, BocNH-
CH(iPr)-CO and NH-CH(H)-CO); 4.3 (dd, J = 5.2, 17.5
Hz, 1H, NH-CH(H)-CO); 5.1 (d, J = 8.8 Hz, 1H,
BocNH-CH(iPr)-CO); 5.2 (d, J = 8.8 Hz, 1H, BocNH-
CH(iPr)); 5.6 (d, J = 8.2 Hz, 1H, CH(PhS)-NH); 6.8 (br,
1H, NH CH2-CO); 7.1–7.3 (m, 6H, ar and NH-CH(SPh)).
MS (NOBA) m/z 595 MH+. Anal. C29H46N4O7S (C, H,
N, O).
4.1.14.7. 1,3-Bis[N-benzyl-N-[N-[(tert-butyloxy)carbo-
nyl]valinyl]amino]-1-phenylsulfenyl-propanone 8g
Compound 8g was prepared from 7g (1.5 g,
2.25 mmol) according to general procedure B and ob-
tained as an oil (0.74 g, 42%). Rf = 0.28 (hexane/EtOAc
1
8:2). Signals in H NMR (CDCl3) could not be assigned
because of their breadth. MS (NOBA) m/z 775 MH+.
Anal. C43H60N4O7S (C, H, N, O).
4.1.16. 1,3-Bis[N-[N-[(tert-butyloxy)carbonyl]valinyl]ami-
no]-1,3-diphenylsulfenyl-propanone 9
4.1.14.8. 1,3-di-[N-(4-methoxybenzyl)-N-[(isobutyloxy)
carbonyl]-1-phenylsulfenyl-propanone 8h
After purification using hexane/EtOAc (9:1) as eluent,
compound 9 was obtained from reaction procedure of 8j
as a white solid (0.36 g, 25%). Rf = 0.51 (hexane:EtOAc
Compound 8h was prepared from 7h (0.35 g,
0.67 mmol) according to general procedure B and ob-
tained as an oil (0.19 g, 44%). Rf = 0.35 (hexane/EtOAc
1
1
8:2). H NMR (CDCl3) δ 0.9 (d, J = 6.9 Hz, 12H,
6:4). H NMR (CDCl3) δ 0.7 (d, J = 13.1 Hz, 6H,
(CH3)2CH); 1.2 (s, 18H, t-Bu); 1.9 (m, 2H, CH(CH3)2);
4.0 (br, 2H, BocNH-CH(iPr)-CO); 5.1 (d, J = 7.9 Hz, 2H,
BocNH-CH(iPr)); 6.2 (d, J = 8.5 Hz, 2H, NH-CH(PhS)),
6.8 (d, J = 8.5 Hz, 2H, CH(PhS)-NH); 7.1–7.2 (m, 10H,
ar). MS (NOBA) m/z 703 MH+. Anal. C35H50N4O7S2 (C,
H, N, O).
(CH3)2CH); 0.8 (d, J = 13.1 Hz, 6H, (CH3)2CH); 1.7 (m,
2H, CH(CH3)2; 3.5 (s, 3H, OCH3); 3.6 (s, 3H, OCH3), 3.8
(s, 2H, N-CH2-CO); 4.1 (br, 4H, p(MeO)PhCH2-N);
4.4–4.5 (br, 4H, iPr-CH2-O), 5.5 (s, 1H, CH-SPh); 6.5 (m,
4H, ar); 6.9 (m, 4H, ar); 7.1–7.2 (m, 5H, ar). MS (NOBA)
m/z 637 MH+. Anal. C35H44N2O7S (C, H, N, O).
4.1.17. General procedure C for the preparation of
compounds 1a–1j and 2a: reduction of phenylthio-ketone
A solution of phenylthio-ketone (1.0 eq.) in ethanol
was treated with NaBH4 (1.5 eq.) from 0 °C to room
temperature until disappearance of starting material on
TLC. After removal of solvent, the residue was taken off
in CH2Cl2 and washed with 5% aqueous citric acid, then
saturated brine, dried over Na2SO4 and evaporated in
4.1.14.9. 1,3-di-[N-(4-methoxybenzyl)-N-[[(N-methyl-N-
phenyl]amino)carbonyl]-1-phenyl sulfenyl-propanone 8i
Compound 8i was prepared from 7i (0.2 g, 0.34 mmol)
according to general procedure B and obtained as an oil
(0.09 g, 40%). Rf = 0.31 (hexane/EtOAc 8:2).1H NMR
(CDCl3) δ 3.0 (s, 3H, CH3N); 3.1 (s, 3H, CH3N); 3.6 (s,
3H, OCH3); 3.7 (s, 3H, OCH3); 3.9 (d, J = 8.7 Hz, 1H,
N-CH(H)-CO); 4.1 (d, J = 9.7 Hz, 4H, p(MeO)PhCH2-