M. Wang et al. / Bioorg. Med. Chem. Lett. 22 (2012) 4713–4718
4717
. The
were determined on
a
MEL-TEMP II capillary tube apparatus and were overnight, basified with saturated K CO and extracted with CH Cl
2
3
2
2
1
13
uncorrected.
H
NMR and
C
NMR spectra were recorded at 500 and
combined organic layers were washed with brine, dried over anhydrous
Na SO , filtered and concentrated in vacuo. The crude product was purified by
silica gel column chromatography (200:6:1 CH Cl /MeOH/NH OH) to afford 5
(1.56 g, 87%) as a white solid, mp 55–56 °C. H NMR (CDCl ): d 7.00 (d,
J = 8.0 Hz, 1H), 6.66 (d, J = 2.5 Hz, 1H), 6.64 (dd, J = 8.0, 2.5 Hz, 1H), 3.77 (s, 3H),
2.88–2.85 (m, 4H), 2.80–2.74 (m, 1H), 2.44 (m, 4H), 2.10–2.04 (m, 2H), 1.97–
1
25 MHz, respectively, on a Bruker Avance II 500 MHz NMR spectrometer
2
4
using tetramethylsilane (TMS) as an internal standard. Chemical shift data for
the proton resonances were reported in parts per million (ppm, d scale) relative
to internal standard TMS (d 0.0), and coupling constants (J) were reported in
hertz (Hz). LC–MS analysis was performed on an Agilent system, consisting of
an 1100 series HPLC connected to a diode array detector and a 1946D mass
spectrometer configured for positive-ion/negative-ion electrospray ionization.
The high resolution mass spectra (HRMS) were obtained using a Waters/
Micromass LCT Classic spectrometer. Chromatographic solvent proportions are
indicated as volume: volume ratio. Thin-layer chromatography (TLC) was run
2
2
4
1
3
1.89 (m, 2H), 1.73–1.67 (m, 1H), 1.66–1.56 (m, 1H). 13C NMR (CDCl
): 158.0,
143.5, 134.4, 129.9, 115.1, 110.6, 60.4, 55.3, 51.7, 51.3, 36.6, 35.4, 28.1, 13.7.
3
+
HRMS (ESI, m/z): calcd for C15
(g). 3-Cyclobutyl-2,3,4,5-tetrahydro-1H-benzo[d]azepin-7-ol (6). A mixture of
compound 5 (0.7 g, 3.03 mmol), 48% HBr (3.44, 30.3 mmol) and n-Bu NI
(112 mg, 0.30 mmol) in AcOH (2.5 mL) was heated and stirred at 100 °C
overnight. The mixture was basified with saturated K CO
until pH ꢀ10 and
extracted with EtOAc. The combined organic layers were washed with brine,
dried over anhydrous Na SO , filtered and concentrated in vacuo. The crude
product was washed with Et O to afford 6 (530 mg, 80%) as a beige solid, mp
201–203 °C. H NMR (DMSO-d ): d 9.07 (s, 1H), 6.86 (s, 1H), 6.51–6.46 (m, 2H),
H22NO ([M+H] ) 232.1701; found 232.1707.
4
2
using Analtech silica gel GF uniplates (5 Â 10 cm ). Plates were visualized
under UV light. Preparative TLC was run using Analtech silica gel UV 254 plates
2
3
2
(
20 Â 20 cm ). Normal phase flash column chromatography was carried out on
EM Science silica gel 60 (230–400 mesh) with a forced flow of the indicated
solvent system in the proportions described below. All moisture- and air-
sensitive reactions were performed under a positive pressure of nitrogen
maintained by a direct line from a nitrogen source. Analytical HPLC was
2
4
2
1
6
2.72 (m, 5H), 2.34 (m, 4H), 2.00 (m, 2H), 1.80 (m, 2H), 1.59 (m, 2H).
performed using a Prodigy (Phenomenex) 5
mobile phase 30:70 CH CN/0.1 N HCO NH , pH 6.0; flow rate 1.0 mL/min; and
UV (254 nm) and -ray (PIN diode) flow detectors. Semi-preparative HPLC was
performed using
l
m C-18 column, 4.6 Â 250 mm;
(h). 6-Chloro-N-methyl-nicotinamide (7). Thionyl chloride (3.48 mL,
47.7 mmol) and DMF (2 drops) were added with stirring to a solution of 6-
chloropyridine-3-carboxylic acid (3.0 g, 19.1 mmol) in toluene (15 mL) at rt.
The mixture was heated and stirred at 100 °C for 2.5 h, then cooled and
concentrated in vacuo to afford 6-chloropyridine-3-carbonyl chloride. The
3
2
4
c
a
Prodigy (Phenomenex)
0 Â 250 mm; mobile phase 25:75 CH CN/0.1 N NH
.0 mL/min; UV (254 nm) and
5
lm
C-18 column, 12 nm,
4
OAc, pH 7.0; flow rate
1
5
3
c
-ray (PIN diode) flow detectors. C18 Plus Sep-
2 2
carbonyl chloride dissolved in CH Cl (15 mL) and methylamine hydrochloride
Pak cartridges were obtained from Waters Corporation (Milford, MA). Sterile
Millex-FG 0.2 filter units were obtained from Millipore Corporation
(3.86 g, 57.2 mmol) was added with stirring portionwise, followed by
trimethylamine (8.0 mL, 57.2 mmol) dropwise at 0 °C. After stirring at 0 °C
for 2 h, the mixture was washed with water, brine, dried over anhydrous
l
m
(
(
Bedford, MA).
b). N-(2,2-Dimethoxyethyl)-2-(3-methoxyphenyl)acetamide (1). Method A:
Na
2
SO
4
, filtered and concentrated in vacuo. The crude product was purified by
Cl /MeOH) to afford 7 (1.59 g,
49%) as a white solid, mp 152–154 °C (lit. 152.8–153.8 °C). H NMR (CDCl
Thionyl chloride (13.2 mL, 180.5 mmol) was added with stirring to
suspension of 3-methoxyphenylacetic acid (10.0 g, 60.2 mmol) in CH Cl
15 mL) dropwise at room temperature (rt). The mixture was heated under
reflux for 1 h and concentrated in vacuo to afford 3-methoxyphenylacetyl
chloride. The acetyl chloride was added as a solution in CH Cl (40 mL) with
stirring to solution of aminoacetaldehyde dimethyl acetal (6.89 mL,
3.2 mmol) and trimethylamine (9.22 mL, 66.2 mmol) in CH Cl (30 mL)
dropwise at 0 °C. After stirring at rt for 1 h, the mixture was washed with
water, 1.0 N HCl, brine and dried over anhydrous Na SO filtered and
concentrated in vacuo. The crude product was purified by silica gel column
chromatography (100:2 CH Cl /MeOH) to afford 1 (13.1 g, 86%) as a yellow oil.
Method B: Thionyl chloride (11.0 mL, 150.4 mmol) and DMF (6 drops) were
added with stirring to solution of 3-methoxyphenylacetic acid (10.0 g,
0.2 mmol) in toluene (100 mL) at rt. The mixture was stirred at rt for 15 h and
concentrated in vacuo to afford 3-methoxyphenylacetyl chloride. The acetyl
chloride was added as a solution in CH Cl (30 mL) with stirring to a solution of
aminoacetaldehyde dimethyl acetal (7.01 mL, 64.4 mmol) and trimethylamine
9.31 mL, 66.8 mmol) in CH Cl (30 mL) dropwise at 0 °C. After stirring at rt for
overnight, the mixture was washed with water, 1.0 N HCl, brine and dried over
anhydrous Na SO , filtered and concentrated in vacuo. The crude product was
purified by silica gel column chromatography (100:2 CH Cl /MeOH) to afford 1
): d 7.29–7.24 (m, 1H), 6.85–6.81
m, 3H), 5.81 (br s, 1H), 4.32 (t, J = 5.5 Hz, 1H), 3.80 (s, 3H), 3.54 (s, 2H), 3.35 (t,
a
silica gel column chromatography (100:3 CH
2
2
21
1
2
2
3
): d
(
8.74 (d, J = 2.5 Hz, 1H), 8.09 (dd, J = 8.5, 2.5 Hz, 1H), 7.41 (d, J = 8.5 Hz, 1H), 6.48
(br s, 1H), 3.03 (d, J = 4.5 Hz, 3H).
2
2
(i).
6-(3-Cyclobutyl-2,3,4,5-tetrahydro-1H-benzo[d]azepin-7-yloxy)-
a
nicotiamide (GSK185071B, 8). NaH (60% dispersion in mineral oil, 55.2 mg,
1.38 mmol) was added with stirring to a solution of compound 6 (200 mg,
0.92 mmol) in DMSO (6 mL) portionwise. The mixture was stirred for 30 min
and 6-chloronicotinamide (288 mg, 1.84 mmol) was added. After the reaction
mixture was heated and stirred at 120 °C overnight, it was cooled and poured
into ice-water, extracted with EtOAc. The combined organic layers were
6
2
2
2
4
,
2
2
washed with brine, dried over anhydrous Na
vacuo. The crude product was purified with preparative TLC plate (200:16:1
CH Cl /MeOH/NH OH) to afford 8 (229 mg, 71%) as a white solid, mp 202–
204 °C. H NMR (DMSO-d ): d 8.61 (d, J = 2.0 Hz, 1H), 8.24 (dd, J = 8.5, 2.5 Hz,
2 4
SO , filtered and concentrated in
a
6
2
2
4
1
6
2
2
1H), 8.04 (br s, 1H), 7.48 (br s, 1H), 7.16 (d, J = 8.5 Hz, 1H), 7.03 (d, J = 8.5 Hz,
1H), 6.93 (d, J = 2.0 Hz, 1H), 6.87 (dd, J = 8.0, 2.5 Hz, 1H), 2.85 (m, 5H), 2.39 (m,
(
2
2
4H), 2.06–1.98 (m, 2H), 1.81 (m, 2H), 1.65–1.51 (m, 2H). 13C NMR (DMSO-d
6
):
165.8, 164.9, 151.4, 147.5, 139.4, 130.0, 125.0, 121.6, 118.6, 110.5, 59.5, 50.7,
+
2
4
50.6, 27.5, 13.2. MS (ESI): 338 ([M+H] , 100%). HRMS (ESI, m/z): calcd for
+
2
2
C
20
H
24
N
3
O
2
([M+H] ) 338.1869; found 338.1874.
1
(
(
15.0 g, 98%) as a yellow oil. H NMR (CDCl
3
(j) 6-(3-Cyclobutyl-2,3,4,5-tetrahydro-1H-benzo[d]azepin-7-yloxy)-N-methyl-
nicotiamide (GSK189254, 9). NaH (60% dispersion in mineral oil, 27.6 mg,
0.69 mmol) was added with stirring to a solution of compound 6 (100 mg,
0.46 mmol) in DMSO (3 mL) portionwise. The mixture was stirred for 30 min
and compound 7 (156 mg, 0.92 mmol) was added. After the reaction mixture
was heated and stirred at 120 °C overnight, it was cooled and poured into ice-
water, extracted with EtOAc. The combined organic layers were washed with
J = 5.5 Hz, 2H), 3.33 (s, 6H).
c). 8-Methoxy-1,3-dihydrobenzo[d]azepine-2-one (2).
(
A
solution of
compound 1 (19.0 g, 75.0 mmol) in AcOH (54 mL) was added with stirring to
concentrated HCl (36 mL). The mixture was stirred at rt overnight and poured
into crushed ice. The precipitate was filtered. The filter cake was dissolved in
CH
2
Cl
2
which was washed with water and brine, dried over anhydrous Na
2
SO
4
,
brine, dried over anhydrous Na
crude product was purified with preparative TLC plate (200:14:1 CH
MeOH/NH OH) to afford 9 (107 mg, 66%) as a white solid, mp 112–115 °C.
NMR (DMSO-d
2 4
SO , filtered and concentrated in vacuo. The
filtered and concentrated in vacuo. The crude product was triturated with Et
2
O
2
Cl
2
/
H
1
1
and filtered to afford 2 (7.45 g, 53%) as a white solid, mp 200–202 °C. H NMR
DMSO-d ): d 9.50 (d, J = 3.5 Hz, 1H), 7.20 (d, J = 8.0 Hz, 1H), 6.88–6.86 (m, 2H),
.26 (d, J = 9.0 Hz, 1H), 6.17 (dd, J = 9.0, 5.0 Hz, 1H), 3.77 (s, 3H), 3.35 (s, 2H).
d). 8-Methoxy-1,3,4,5-tetrahydrobenzo[d]azepine-2-one (3). solution of
4
(
6
(
6
6
): d 8.57 (d, J = 2.5 Hz, 1H), 8.51–8.49 (m, 1H), 8.20 (dd, J = 8.5,
2.5 Hz, 1H), 7.15 (d, J = 8.5 Hz, 1H), 7.03 (d, J = 8.5 Hz, 1H), 6.92 (d, J = 2.5 Hz,
1H), 6.86 (dd, J = 8.0, 2.5 Hz, 1H), 2.85–2.75 (m, 8H), 2.36 (m, 4H), 2.03–1.98
A
compound 2 (6.0 g, 31.7 mmol) in AcOH (100 mL) was hydrogenated over 10%
Pd/C (600 mg) at 60 psi for 8 h. The catalyst was filtered off through a layer of
Celite, and the filtrate was concentrated in vacuo. The crude product was
(m, 2H), 1.82–1.74 (m, 2H), 1.64–1.52 (m, 2H). 13C NMR (DMSO-d
6
): 164.8,
164.6, 151.4, 147.0, 143.8, 139.0, 138.8, 120.0, 125.3, 121.6, 118.5, 110.5, 59.6,
+
50.8, 50.7, 27.6, 26.1, 13.2. MS (ESI): 352 ([M+H] , 100%). HRMS (ESI, m/z):
+
triturated with Et
2
O to afford 3 (5.83 g, 96%) as a pale pink solid, mp 170–
3
calcd for C21
H
26
N
3
O
2
([M+H] ) 352.2025; found 352.2026.
1
1
6
2
72 °C. H NMR (CDCl ): d 7.03 (d, J = 8.5 Hz, 1H), 6.75 (dd, J = 8.5, 3.0 Hz, 1H),
.69 (d, J = 8.0 Hz, 1H), 6.32 (br s, 1H), 3.80 (s, 2H), 3.78 (s, 3H), 3.56–3.53 (m,
H), 3.06 (t, J = 6.0 Hz, 2H).
(k).
6-(3-Cyclobutyl-2,3,4,5-tetrahydro-1H-benzo[d]azepin-7-yloxy)-N-
11
11
11
11
2
[ C]methyl-nicotiamide ([ C]GSK189254, [ C]9). [ C]CO was produced by
14 11 3
the N(p,a) C nuclear reaction in the small volume (9.5 cm ) aluminum gas
(
(
e). 7-Methoxy-2,3,4,5-tetrahydro-1H-benzo[d]azepine (4). Borane in THF
1 M, 75 mL) was added with stirring to a suspension of compound 3 (5.0 g,
target provided with the Siemens RDS-111 Eclipse cyclotron. The target gas
consisted of 1% oxygen in nitrogen purchased as a specialty gas from Praxair,
2
6.1 mmol) in THF (125 mL) dropwise at 0 °C. The mixture was heated under
reflux overnight. The solution was cooled to 0 °C, and quenched with 3 N HCl
75 mL). After stirring at rt for 15 min, the solution was concentrated in vacuo
to remove THF. The aqueous solution was washed with EtOAc, then cooled to
°C and basified with solid KOH until pH >10. The liberated amine was
extracted with Et O, dried over anhydrous K CO , filtered and concentrated in
vacuo to afford 4 (3.0 g, 65%) as a pale yellow oil. H NMR (CDCl
J = 8.0 Hz, 1H), 6.67 (d, J = 2.5 Hz, 1H), 6.63 (dd, J = 8.0, 2.5 Hz, 1H), 3.77 (s, 3H),
.96–2.91 (m, 4H), 2.87–2.83 (m, 4H), 2.24 (br s, 1H).
f). 7-Methoxy-3-cyclobutyl-2,3,4,5-tetrahydro-1H-benzo[d]azepine
Cyclobutanone (0.88 mL, 11.6 mmol) was added with stirring to a solution of
compound 4 (1.37 g, 7.74 mmol) in 2.5% AcOH in CH Cl (5 mL) dropwise at
°C. The mixture was stirred at rt for 30 min and NaBH(OAc) (2.46 g,
1.6 mmol) was added portionwise. The reaction mixture was then stirred
Indianapolis, IN. Typical irradiations used for the development were 55
lA
beam current and 15 min1 on target. The production run produced
1
(
approximately 28.5 GBq of [ C]CO
the precursor GSK185071B (8) (0.1–0.3 mg) was dissolved in DMSO (300
To this solution was added 2 N NaOH (2 L). No carrier-added (high specific
OTf that was produced by the gas-phase production
2
at EOB. In a small reaction vial (5 mL),
l
L).
0
l
11
2
2
3
activity) [ C]CH
3
18 11
1
11
11
3
): d 7.00 (d,
2 4 3
method from [ C]CO through [ C]CH and [ C]CH Br with silver triflate
(AgOTf) column was passed into the reaction vial at rt, until radioactivity
reached a maximum (ꢀ2 min), and then the reaction vial was isolated and
heated at 80 °C for 3 min. The contents of the reaction vial were diluted with
NaHCO (0.1 M, 1 mL), and injected onto the semi-preparative HPLC column
3
with 3 mL injection loop for purification. The product fraction was collected in
a recovery vial containing 30 mL water. The diluted tracer solution was then
2
(
(5).
2
2
0
1
3
passed through
a C-18 Sep-Pak Plus cartridge, and washed with water