4306 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 22
Yasuma et al.
(1H,m), 2.55 (1H,dd,J ) 7.4 & 14.8Hz), 2.90 (1H,dd,J
14.8Hz), 3.4-3.6 (1H,m), 3.7-3.9 (1H,m), 7.0-7.3 (5H,m), 7.5-
7.7 (3H,m), 8.0-8.4 (4H,m), 8.68 (1H,d,J ) 8.2Hz), 8.74 (1H,s).
Anal. (C25H28N2O4S) C, H, N.
N-(2-Ben zyl-3-p h en ylp r op ion yl)-L-t r yp t op h a n a l (31).
31 was synthesized in the same manner as described for
preparation of 12: colorless prisms; yield 69%; mp 142-144
°C; [R]D +14.1° (c ) 0.57, CHCl3); 1H NMR (CDCl3) δ
2.5-2.7 (1H,m), 2.7-3.2 (6H,m), 4.50 (1H,q,J ) 6.0Hz), 5.55
(1H,d,J ) 6.6Hz), 6.36 (1H,d,J ) 2.4Hz), 7.0-7.4 (14H,m), 7.89
(1H,brs), 9.19 (1H,s). Anal. (C20H20N2O2‚1/4H2O) C, H, N.
(1H,m), 5.13 (1H,d,J ) 7.0Hz), 6.42 (1H,d,J ) 2.6Hz), 7.0-
7.9 (14H,m), 7.93 (1H,brs). Anal. (C27H28N2O2‚1/4H2O)
C, H, N.
)
Gen er a l P r oced u r e for th e In tr od u ction of N-Su lfon yl
Gr ou p . N-(1-Na p h th a len ylsu lfon yl)-L-isoleu cyl-L-tr yp -
top h a n ol. Cbz group of N-Cbz-L-isoleucyl-L-tryptophanol (55
g, 0.13 mol) was deprotected by the general procedure. The
obtained amino compound was dissolved in DMF (300 mL),
and 1-naphthalenylsulfonyl chloride (30 g, 0.13 mol) and
4-N,N-dimethylaminopyridine (17 g, 0.14 mol) were added to
the solution with cooling. The whole was stirred at the same
temperature for 2 h and then concentrated in vacuo. The
residue was suspended in ethyl acetate, and the suspension
was washed successively with aqueous citric acid, H2O, aque-
ous NaHCO3, and brine, dried over MgSO4, and concentrated
under reduced pressure. The residual light brown oil was
crystallized from CH2Cl2-ether to afford the title compound
as a white solid (51 g, 82%): mp 150-151 °C; [R]D -77.7°
N-Cbz-L-tr yp top h a n N,O-Dim eth ylh yd r oxyla m id e. To
an ice-cooled and stirred solution of N-Cbz-L-tryptophan (40.0
g, 118 mmol), N,O-dimethylhydroxylamine hydrochloride (12.0
g, 123 mmol), and triethylamine (17.6 mL,126 mmol) in DMF
(300 mL) were added HOBt (20.0 g, 131 mmol) and WSC (24.8
g, 129 mmol), and the whole was stirred at room temperature
for 15 h. The reaction mixture was concentrated in vacuo. The
residue was suspended in ethyl acetate, and the suspension
was washed successively with aqueous citric acid, H2O, aque-
ous NaHCO3, and brine, dried over MgSO4, and concentrated
under reduced pressure. The residual pale brown solid was
washed with ethyl acetate-hexane to afford the title compound
as a white solid (42 g, 93%): mp 131-132 °C; [R]D -21.0° (c )
0.56, MeOH); 1H NMR (CDCl3) δ 3.0-3.2 (1H,m), 3.15 (3H,s),
3.27 (1H,dd,J ) 5.6 & 15.0Hz), 3.66 (3H,s), 5.00 (1H,d,J )
11.4Hz), 5.13 (1H,d,J ) 11.4Hz), 5.51 (1H,d,J ) 8.2Hz), 6.98
(1H,d,J ) 2.2Hz), 7.0-7.4 (8H,m), 7.58 (1H,d,J ) 7.4Hz), 8.11
(1H,brs). Anal. (C21H23N3O4) C, H, N.
N-Cbz-L-isoleu cyl-L-tr yp top h a n N,O-Dim eth ylh yd r ox-
yla m id e. The title compound was synthesized in the same
manner as described for preparation of N-Cbz-L-isoleucyl-L-
tryptophanol: colorless amorphous solid; yield 92%; [R]D
-36.6° (c ) 0.55, MeOH); 1H NMR (CDCl3) δ 0.7-1.2 (7H,m),
1.2-1.5 (1H,m), 1.7-1.9 (1H,m), 3.1-3.2 (1H,m), 3.15 (3H,s),
3.27 (1H,dd,J ) 6.0 & 14.8Hz), 3.69 (3H,s), 4.1-4.2 (1H,m),
5.11 (2H,s), 5.2-5.4 (2H,m), 6.55 (1H,d,J ) 8.2Hz), 6.99
(1H,d,J ) 1.8Hz), 7.0-7.4 (8H,m), 7.55 (1H,d,J ) 8.2Hz), 7.92
(1H,brs). Anal. (C27H34N4O5‚1/2H2O) C, H, N.
N-(1-Na p h th a len ylsu lfon yl)-L-isoleu cyl-L-tr yp top h a n
N,O-Dim eth ylh yd r oxyla m id e. The title compound was
synthesized in the same manner as described for preparation
of N-(1-naphthalenylsulfonyl)-L-isoleucyl-L-tryptophanol. The
obtained product was dissolved in toluene, and the solution
was concentrated in vacuo to give a pale yellow amorphous
solid; yield 83%; [R]D +30.2° (c ) 0.75, MeOH); 1H NMR
(CDCl3) δ 0.5-1.0 (7H,m), 1.1-1.4 (1H,m), 1.5-1.7 (1H,m),
2.77 (1H,dd,J ) 5.6 & 15.0Hz), 2.92 (1H,dd,J ) 6.0 & 15.0Hz),
3.04 (3H,s), 3.44 (3H,s), 3.5-3.6 (1H,m), 4.8-5.0 (1H,m), 5.74
(1H,d,J ) 8.8Hz), 6.48 (1H,d,J ) 7.2Hz), 6.90 (1H,s), 7.0-7.9
(9H,m), 8.18 (1H,d,J ) 7.4Hz), 8.20 (1H,brs), 8.68 (1H,d,J )
8.6Hz). Anal. (C29H34N4O5S‚1/2toluene) C, H, N.
N-(1-Na p h t h a len ylsu lfon yl)-L-isoleu cyl-L-t r yp t op h a -
n a l (12). To a stirred solution of N-(1-naphthalenylsulfonyl)-
L-isoleucyl-L-tryptophan N,O-dimethylhydroxylamide (21 g,
38.1 mmol) in absolute THF (200 mL) was added dropwise 1.5
M diisobutylaluminum hydride toluene solution (107 mL,161
mmol) at -60 °C. After stirring at -50 °C for 4 h, the reaction
mixture was poured into aqueous citric acid, extracted with
AcOEt, washed successively with aqueous citric acid, H2O,
aqueous NaHCO3, and brine, dried over MgSO4, and concen-
trated under reduced pressure. The residual yellow oil was
crystallized from ethyl acetate-hexane to give 12 as a pale
yellow solid (15.3 g, 81%).
1
(c ) 0.57, CHCl3); H NMR (CDCl3) δ 0.42 (3H,d,J ) 6.6Hz),
0.52 (3H,t,J ) 6.6Hz), 0.5-0.8 (1H,m), 0.9-1.1 (1H,m), 1.5-
1.8 (1H,m), 2.5-2.7 (2H,m), 2.82 (1H,dd,J ) 7.2 & 14.4Hz),
3.3-3.6 (3H,m), 4.0-4.2 (1H,m), 5.36 (1H,d,J ) 6.6Hz), 6.37
(1H,d,J ) 8.2Hz), 6.99 (1H,d,J ) 2.2Hz), 7.1-7.7 (7H,m), 7.94
(1H,d,J ) 7.8Hz), 8.06 (1H,d,J ) 8.0Hz), 8.17 (1H,brs), 8.22
(1H,d,J ) 7.4Hz), 8.66 (1H,d,J ) 8.8Hz). Anal. (C27H31N3O4S)
C, H, N.
N-(1-Na p h th a len ylsu lfon yl)-L-isoleu cyl-L-p h en yla la n i-
n ol. The title compound was synthesized in the same manner
as described for preparation of N-(1-naphthalenylsulfonyl)-L-
isoleucyl-L-tryptophanol: colorless crystals; yield 87%; mp
169-170 °C; [R]D -108.3° (c ) 0.65, CHCl3); 1H NMR (CDCl3)
δ 0.39 (3H,d,J ) 5.0Hz), 0.54 (3H,t,J ) 6.8Hz), 0.6-1.1 (2H,m),
1.6-1.8 (1H,m), 2.47 (1H,dd,J ) 8.2 & 14.0Hz), 2.57 (1H,t,J
) 6.0Hz), 2.73 (1H,dd,J ) 7.0 & 14.0Hz), 3.2-3.6 (3H,m), 4.0-
4.2 (1H,m), 5.34 (1H,d,J ) 6.0Hz), 6.43 (1H,dJ ) 8.2Hz), 7.1-
7.4 (5H,m), 7.5-7.8 (3H,m), 7.97 (1H,d,J ) 7.8Hz), 8.10 (1H,d,J
) 8.4Hz), 8.25 (1H,dd,J ) 1.2 & 7.2Hz), 8.68 (1H,d,J ) 8.6Hz).
Anal. (C25H30N2O4S) C, H, N.
Gen er a l P r oced u r e for th e P y‚SO3-DMSO Oxid a tion .
N-(1-Na p h t h a len ylsu lfon yl)-L-isoleu cyl-L-t r yp t op h a n a l
(12). To an ice-cooled and stirred solution of N-(1-naphtha-
lenylsulfonyl)-L-isoleucyl-L-tryptophanol (19.4 g, 39.3 mmol)
and triethylamine (11.0 mL, 78.9 mmol) in DMSO (140 mL)
was added portionwise a solution of SO3‚Py (12.5 g, 78.5 mmol)
in DMSO (60 mL), and the whole was stirred at room
temperature for 50 min. The reaction mixture was poured into
ice-water and extracted with ethyl acetate. The extract was
washed successively with aqueous citric acid, H2O, aqueous
NaHCO3, and brine, dried over MgSO4, and concentrated
under reduced pressure. The residual pale yellow oil was
crystallized from ethyl acetate-hexane to afford 12 as a pale
yellow solid (9.6 g, 50%): mp 145-146 °C; [R]D -48.9° (c )
1
0.50, CHCl3); H NMR (CDCl3) δ 0.61 (3H,d,J ) 6.6Hz), 0.63
(3H,t,J ) 6.2Hz), 0.8-0.9 (1H,m), 1.1-1.3 (1H,m), 1.6-1.7
(1H,m), 2.87 (2H,d,J ) 6.8Hz), 3.56 (1H,dd,J ) 5.4 & 8.2Hz),
4.48 (1H,dd,J ) 6.8 & 13.6Hz), 5.38 (1H,d,J ) 8.0Hz), 6.29
(1H,d,J ) 6.6Hz), 6.95 (1H,d,J ) 2.4Hz), 7.1-7.8 (7H,m), 7.9-
8.3 (4H,m), 8.67 (1H,d,J ) 8.8Hz), 9.30 (1H,s). Anal.
(C27H29N3O4S) C, H, N.
N-(2-Tr iflu or om eth ylp h en ylca r ba m oyl)-L-isoleu cyl-L-
tr yp top h a n a l (6). 6 was synthesized in the same manner
as described for preparation of 12: pale yellow solid; yield 36%;
1
mp 185-186 °C dec; [R]D -18.7° (c ) 0.50, DMSO); H NMR
(DMSO-d6) δ 0.7-1.2 (7H,m), 1.3-1.5 (1H,m), 1.6-1.8 (1H,m),
3.02 (1H,dd,J ) 8.2 & 15.0Hz), 3.25 (1H,dd,J ) 5.4 & 15.0Hz),
4.27 (1H,dd,J ) 6.2 & 8.2Hz), 4.43 (1H,q,J ) 7.0Hz), 6.9-7.7
(9H,m), 7.93 (1H,d,J ) 8.4Hz), 8.06 (1H,s), 8.60 (1H,d,J )
6.6Hz), 9.50 (1H,s), 10.88 (1H,brs). Anal. (C25H27N4O3F3‚1/
2H2O) C, H, N.
Biologica l P r oced u r es. 1. Deter m in a tion of Hu m a n
Ca th ep sin L In h ibitor y Activity. Recombinant human
cathepsin L was diluted with a diluent [0.1% Brij 35 (Sigma
Chemical Co.)] to a concentration of 1 µg/mL. To 1 µL of this
enzyme dilution were added 46 µL of the diluent, 2 µL of 0.1
M DTT, and 25 µL of an activator/buffer (340 mM sodium
acetate, 60 mM acetic acid, 4 mM disodium EDTA, pH 5.5).
N-(1-Na p h th a len ylsu lfon yl)-L-isoleu cyl-L-p h en yla la n i-
n a l (21). 21 was synthesized in the same manner as described
for preparation of 12: colorless needles; yield 67%; mp 138-
To this mixture were added a 1 µL sample, diluted to 10-2
M
1
139 °C; [R]D -24.3° (c ) 0.60, DMSO); H NMR (DMSO-d6) δ
with dimethyl sulfoxide (DMSO), and 25 µL of 20 µM Z-Phe-
0.5-0.7 (6H,m), 0.8-1.0 (1H,m), 1.1-1.4 (1H,m), 1.4-1.6
Arg-NMec (enzyme substrate solution), followed by incubation