M. Wang et al. / Bioorg. Med. Chem. Lett. 24 (2014) 4455–4459
4459
beige solid, mp 300–302 °C. 1H NMR (DMSO-d6): d 12.07 (s, 1H), 7.99 (d,
J = 3.0 Hz, 1H), 7.44 (s, 1H), 7.13 (s, 1H), 3.91 (s, 3H), 3.87 (s, 3H). A solution of
compound 1b (8.0 g, 35.5 mmol) in formamide (80 mL) was heated to 168–
170 °C under N2 atmosphere overnight. The reaction mixture was cooled and
the resultant precipitate was filtered, washed with water, ether to afford 2
(6.48 g, 89%) as a beige solid.
1.99 (m, 2H), 1.68–1.62 (m, 2H), 1.42 (s, 9H). LC-MS (ESI, m/z): calcd for
C25H29ClFN4O4 ([M+H]+) 503.2, found 503.1.
(l) N-(3-Chloro-2-fluorophenyl)-7-methoxy-6-(piperidin-4-yloxy)quinazolin-
4-amine (10): A solution of compound 9 (1.1 g, 2.19 mmol) in TFA (10 mL)
was stirred at rt for 2 h. The solvent was removed under vacuum and the trace
of TFA was taken away with CH2Cl2. The residual was triturated with Et2O and
stored in refrigerator overnight; the resultant solid was collected by filtration
and wash with Et2O, cold CH2Cl2 to afford 10 (1.09 g, 97%) as a cream solid, mp
202–204 °C. 1H NMR (DMSO-d6): d 10.88 (br s, 1H), 8.73 (m, 3H), 8.09 (s, 1H),
7.62 (t, J = 7.0 Hz, 1H), 7.54 (t, J = 7.0 Hz, 1H), 7.39–7.35 (m, 2H), 4.82 (s, 1H),
4.01 (s, 3H), 3.29 (m, 2H), 3.15 (m, 2H), 2.20 (m, 2H), 1.98–1.95 (m, 2H). LC-MS
(ESI, m/z): calcd for C20H20ClFN4O2 ([M+H]+) 403.2, found 403.1. The free base
was prepared by dissolving TFA salt (1.10 g) in water, basified with 1 N NaOH
to pH ꢀ9 at 0 °C. The mixture was extracted with CH2Cl2. The combined organic
layers were washed with brine, dried over anhydrous Na2SO4, filtered and
concentrated under vacuum to afford a pale yellow solid (748.8 mg).
(m) 2-(4-((4-((3-Chloro-2-fluorophenyl)amino)-7-methoxyquinazolin-6-yl)oxy)
(e) 6-Hydroxy-7-methoxyquinazolin-4(3H)-one (3): A mixture of compound 2
(9.11 g, 44.3 mmol), L-methionine (7.25 g, 48.6 mmol) and methanesulfonic
acid (65 mL) was heated to 120 °C for 18 h. The reaction mixture was cooled
and poured into ice-water, then neutralized with 40% NaOH to pH ꢀ7. The
resultant precipitate was filtered, washed with water and dried under vacuum.
The crude product was recrystallized from MeOH to afford 3 (5.06 g, 60%) as a
pale yellow solid, mp 306 °C (dec.). 1H NMR (DMSO-d6): d 11.9 (s, 1H), 9.82 (s,
1H), 7.92 (s, 1H), 7.39 (s, 1H), 7.10 (s, 1H), 3.91 (s, 3H).
(f) 7-Methoxy-4-oxo-3,4-dihydroquinazolin-6-yl acetate (4):
A suspension of
compound (3.88 g, 20.2 mmol), pyridine (4 mL) and DMAP (122 mg,
3
1.0 mmol) in acetic anhydride (30 mL) was heated to 100 °C and stirred under
N2 atmosphere for 6 h. The reaction mixture was cooled and poured into ice-
water. The resultant precipitate was filtered, washed with water and dried
under vacuum to afford 4 (1.88 g, 40%) as a beige solid, mp 303–305 °C. 1H
NMR (DMSO-d6): d 12.2 (s, 1H), 8.09 (s, 1H), 7.75 (s, 1H), 7.28 (s, 1H), 3.91 (s,
3H), 2.30 (s, 3H). LC-MS (ESI, m/z): calcd for C11H11N2O4 ([M+H]+) 235.1, found
235.1.
(g) 4-Chloro-7-methoxyquinazolin-6-yl acetate (5): A suspension of compound 4
(1.80 g, 7.69 mmol) and N,N-diethylaniline (1.7 mL) in POCl3 (9 mL) was
immersed in a preheated oil bath (100 °C) and stirred at 100 °C for 30 min. The
reaction mixture was cooled to 80 °C and stirred for further 30 min. Excess
POCl3 was removed under vacuum, and the residual was triturated with
toluene three times. Ice-water was added, and the resultant precipitate was
filtered, washed with cooled water and dried under vacuum to afford 5 (1.83 g,
94%) as a gray solid, which was used for next step.
(h) 4-((3-Chloro-2-fluorophenyl)amino)-7-methoxyquinazolin-6-yl acetate (6): A
suspension of compound 5 (1.70 g, 6.75 mmol) and 3-chloro-2-fluoroaniline
(982 mg, 6.75 mmol) in i-PrOH (50 mL) was heated to reflux for 3 h. The
solvent was removed under vacuum, and the residual was recrystallized in
CH3CN to afford 6 (2.51 g, 93%) as a pale brown solid, mp 209–210 °C. 1H NMR
(DMSO-d6): d 9.82 (br s, 1H), 8.48 (s, 1H), 8.23 (s, 1H), 7.53–7.47 (m, 2H), 7.37
(s, 1H), 7.28 (t, J = 8.0 Hz, 1H), 3.96 (s, 3H), 2.37 (s, 3H). LC-MS (ESI, m/z): calcd
for C17H14ClFN3O3 ([M+H]+) 362.0, found 362.0.
(i) 4-((3-Chloro-2-fluorophenyl)amino)-7-methoxyquinazolin-6-ol (7): To a stir-
red solution of compound 6 (2.30 g, 5.79 mmol) in MeOH (50 mL) was added
concentrated ammonia (4.0 mL). The reaction mixture was stirred at rt for
18 h. The resultant precipitate was filtered, and washed with MeOH to afford 7
(1.54 g, 83%) as a pale yellow solid, mp 280–282 °C. 1H NMR (DMSO-d6): d 9.75
(s, 1H), 9.48 (s, 1H), 8.35 (s, 1H), 7.66 (s, 1H), 7.52 (t, J = 6.5 Hz, 1H), 7.45 (t,
J = 7.0 Hz, 1H), 7.26 (t, J = 8.0 Hz, 1H), 7.21 (s, 1H), 3.98 (s, 3H).
(j) 1-tert-Butoxycarbonyl-4-methanesulfonyloxypiperidine (8): To a stirred solu-
tion of 4-hydroxypiperidine (5.0 g, 49.4 mmol) in CH2Cl2 (50 mL) and 1,4-
dioxane (50 mL) was added Boc2O (10.69 g, 49.4 mmol). After the reaction
mixture was stirred at rt for 2 h, the solvent was removed under vacuum and
the residual was partitioned between EtOAc and saturated NH4Cl. The
combined organic layers were washed with brine, dried over anhydrous
Na2SO4, filtered and concentrated under vacuum to give a white solid. To a
stirred solution of the above white solid in CH2Cl2 (50 mL), Et3N (7.17 mL,
51.0 mmol) and methanesulfonyl chloride (3.80 mL, 49.4 mmol) were added at
0 °C. After the reaction mixture was stirred at rt overnight, it was washed with
saturated NH4Cl. The organic layer was washed with saturated NaHCO3 and
brine, dried over anhydrous Na2SO4, filtered and concentrated under vacuum.
The crude product was recrystallized in Et2O-hexanes to afford 8 (12.2 g, 88%)
as a white solid, mp 66–68 °C (lit.21 67–68 °C). 1H NMR (CDCl3): d 4.89–4.85
(m, 1H), 3.72–3.67 (m, 2H), 3.32–3.28 (m, 2H), 3.03 (s, 3H), 1.98–1.93 (m, 2H),
1.84–1.77 (m, 2H), 1.45 (s, 9H).
piperidin-1-yl)-N-methylacetamide (AZD8931, 11a): To
a stirred mixture of
compound 10 (480 mg, 1.19 mmol), KI (68.8 mg, 0.41 mmol) and K2CO3
(206.1 mg, 1.49 mmol) in CH3CN (15 mL) was added a solution of 2-chloro-
N-methylacetamide (128.5 mg, 1.19 mmol) in CH3CN (3 mL) dropwise. The
reaction mixture was heated to reflux for 2 h. The solvent was removed under
vacuum, and the residual was partitioned between CHCl3 and water. The
combined organic layers were washed with brine, dried over anhydrous
Na2SO4, filtered and concentrated under vacuum. The crude product was
purified by column chromatography with concentrated ammonia in MeOH
(1:7)/CH2Cl2 (1:10) to afford 11a (397 mg, 70%) as a white solid, mp 106–
107 °C. 1H NMR (CDCl3): d 8.69 (s, 1H), 8.41–8.37 (m, 3H), 7.54 (s, 1H), 7.29 (s,
1H), 7.26 (s, 1H), 7.17–7.16 (m, 2H), 7.13 (s, 1H), 4.50–4.45 (m, 1H), 4.00 (s,
3H), 3.04 (s, 2H), 2.86–2.81 (d+m, J = 5.0 Hz, 5H), 2.44–2.40 (m, 2H), 2.10–2.06
(m, 2H), 1.98–1.91 (m, 2H). LC-MS (ESI, m/z): calcd for C23H26ClFN5O3 ([M+H]+)
474.2, found 474.2. HRMS (ESI-TOF, m/z): calcd for C23H26ClFN5O3 ([M+H]+)
474.1708, found 474.1696.
(n)
2-(4-((4-((3-Chloro-2-fluorophenyl)amino)-7-methoxyquinazolin-6-yl)oxy)
piperidin-1-yl)acetamide (N-desmethyl-AZD8931, 11b): To a stirred solution
of compound 10 (213 mg, 0.53 mmol) in CH2Cl2 (5 mL) was added DIPEA
(0.14 mL, 0.80 mmol), followed by 2-bromoacetamide (110 mg, 0.80 mmol).
The reaction mixture was stirred at rt overnight. The resultant precipitate was
collected by filtration and washed with CH2Cl2. The crude solid was recrys-
tallized in CH3CN to afford 11b (151 mg, 62%) as a white solid, mp 241–243 °C.
1H NMR (DMSO-d6): d 9.58 (s, 1H), 8.37 (s, 1H), 7.83 (s, 1H), 7.55–7.48 (m, 2H),
7.29 (t, J = 8.0 Hz, 1H), 7.24 (s, 1H), 7.22 (s, 1H), 7.12 (s, 1H), 4.59–4.55 (m, 1H),
3.94 (s, 3H), 2.91 (s, 2H), 2.79–2.77 (m, 2H), 2.42–2.39 (m, 2H), 2.07–2.05 (m,
2H), 1.82–1.77 (m, 2H). LC-MS (ESI, m/z): calcd for C22H24ClFN5O3 ([M+H]+)
460.1, found 460.1.
(o)
2-(4-((4-((3-Chloro-2-fluorophenyl)amino)-7-methoxyquinazolin-6-yl)oxy)
piperidin-1-yl)-N-[11C]methylacetamide} ([11C]AZD8931,
[
11C]11a): 11C]CO2
[
was produced by the 14N(p, 11C nuclear reaction in the small volume
a)
(9.5 cm3) aluminum gas 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, Indianapolis, IN. Typical irradiations used for the
development were 55
run produced approximately 45.5 GBq of [11C]CO2 at EOB. In a small reaction
vial (5 mL), the precursor 11b (0.3–0.5 mg) was dissolved in DMSO (400 L). To
lA beam current and 30 min on target. The production
l
this solution was added NaH (1 mg). No carrier-added (high specific activity)
[
[
11C]CH3OTf that was produced by the gas-phase production method23 from
11C]CO2 through [11C]CH4 and [11C]CH3Br 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 NaHCO3 solution (0.1 M,
1 mL), and injected onto the semi-preparative RP HPLC column 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 passed
through a C-18 Sep-Pak Plus cartridge, and washed with water (5 mL Â 4). The
cartridge was eluted with EtOH (1 mL Â 2), followed by 10 mL saline, to release
(k) tert-Butyl 4-((4-((3-chloro-2-fluorophenyl)amino)-7-methoxyquinazolin-6-
yl)oxy)piperidine-1-carboxylate (9): To
a solution of compound 7 (1.44 g,
4.51 mmol) in DMA (15 mL) was added compound 8 (378 mg, 1.35 mmol)
and CsF (685 mg, 4.51 mmol). The reaction mixture was heated to 85 °C and
stirred. At intervals of 2 h, 4 h and 6 h, each time compound 8 (378 mg,
1.35 mmol) and CsF (685 mg, 4.51 mmol) were added. After the final addition,
the reaction mixture was stirred at 85 °C for further 6 h. The solvent was
removed under vacuum and the residual was partitioned between CH2Cl2 and
water. The combined organic layers were washed with brine, dried over
anhydrous Na2SO4, filtered and concentrated under vacuum. The crude product
was purified by column chromatography with MeOH/CH2Cl2 (1:25) to afford 9
(1.37 g, 60%) as a pale yellow solid, mp 200–201 °C. 1H NMR (DMSO-d6): d 9.59
(s, 1H), 8.39 (s, 1H), 7.88 (s, 1H), 7.55–7.48 (m, 2H), 7.29 (t, J = 8.0 Hz, 1H), 7.24
(s, 1H), 4.71 (s, 1H), 3.95 (s, 3H), 3.71–3.69 (m, 2H), 3.29–3.26 (m, 2H), 2.01–
[
11C]11a. The eluted product was then sterile-filtered through a sterile vented
Millex-FG 0.2 lm filter, and collected into a sterile vial. Total radioactivity
(4.6–8.2 GBq) was assayed and total volume (10–11 mL) was noted for tracer
dose dispensing. The overall synthesis, purification and formulation time was
30–40 min from EOB. Retention times in the analytical HPLC system were: tR
11b =3.58 min, tR 11a =5.53 min, tR
semi-preparative HPLC system were: tR 11b =3.86 min, tR 11a =9.24 min, tR
[
11C]11a =5.68 min. Retention times in the
[
11C]11a =9.37 min. The radiochemical yield of [11C]11a was 40–50% decay
corrected to EOB, based on [11C]CO2.
Wang, Min
