Practical and high-yield syntheses of dihydromorphine from tetrahydrothebaine and efficient syntheses of (8S)-8-bromomorphide

Article abstract of DOI:10.1021/jo0206871

A practical method for the conversion of tetrahydrothebaine to dihydromorphine in 92% yield is described. The procedure should allow more efficient production of opium products and may be easily modified for large-scale synthesis. The conversion of codeine to (8S)-8-bromomorphide, a potentially valuable intermediate to 6-demethoxyoripavine and derivatives, is also described. The absolute configuration of (8S)-8-bromomorphide was determined by a single-crystal X-ray diffraction study of the hydrobromide salt.

Full text of DOI:10.1021/jo0206871

P r a ctica l a n d High -Yield Syn th eses of
Dih yd r om or p h in e fr om
Tetr a h yd r oth eba in e a n d Efficien t
Syn th eses of (8S)-8-Br om om or p h id e
Scheme 1), a direct precursor of the pharmacologically
useful hydromorphone (9, Scheme 2). DHM (8) is also a
starting material for dihydrocodeinone (4) via phenolic
4
methylation to dihydrocodeine (10, Scheme 1) and oxida-
tion5 of the alcohol function. Dihydrocodeinone (4) is an
,6
†
‡
Anna K. Przybyl, J udith L. Flippen-Anderson,
important drug, being the third most widely prescribed
†
,†
Arthur E. J acobson, and Kenner C. Rice*
2
opium product in the U.S. Dihydrocodeinone (4) is
7
Laboratory of Medicinal Chemistry, Building 8,
Room B1-22, National Institutes of Diabetes and Digestive
and Kidney Diseases, National Institutes of Health,
convertible in high yield to codeine (7), morphine (6),
and thebaine (2) on which the entire spectrum of opium-
derived medical narcotics and their antagonists is based.
We have now examined the conversion of THT (1) to
8
Center Drive, MSC 0815, Bethesda, Maryland 20892,
and Laboratory for the Structure of Matter,
Naval Research Laboratory, Washington, D.C. 20375
8
DHM (8) using material from the catalytic reduction of
8
9 kg of thebaine (2) to 8,14-dihydrothebaine (3) ac-
kr21f@nih.gov
complished at Merck and Co. in 1947. The latter was
Received November 7, 2002
required for the synthesis of methyldihydromorphinone
9
(
metapon, 11, Scheme 2) and related compounds in an
Abstr a ct: A practical method for the conversion of tetrahy-
drothebaine to dihydromorphine in 92% yield is described.
The procedure should allow more efficient production of
opium products and may be easily modified for large-scale
synthesis. The conversion of codeine to (8S)-8-bromomor-
phide, a potentially valuable intermediate to 6-demethoxy-
oripavine and derivatives, is also described. The absolute
configuration of (8S)-8-bromomorphide was determined by
a single-crystal X-ray diffraction study of the hydrobromide
salt.
1
0,11
early opiate program
aimed at the development of
strong analgesics with fewer side effects than morphine
6). Crude crystalline THT (1) hydrochloride trihydrate
from the Merck reduction showed about 7% of a higher
spot on thin-layer chromatography (TLC) that we
(
R
f
identified as neopine methyl ether (12, Scheme 2) from
the NMR spectrum, by comparison with the original
8
sample of Small. Hydrogenation of the crude mixture
converted the neopine methyl ether (12) to the desired
THT (1) that was purified to give starting material for
O-demethylation to DHM (8).
Narcotic drugs and their antagonists derived from the
opium poppy, Pavaver somniferum, are essential for the
effective practice of modern medicine. The chemistry of
these drugs has been extensively investigated, and one
goal has been their more efficient and economical produc-
The O-demethylation of THT (1) with refluxing 48%
aqueous HBr for 1.0 h to give dihydromorphine (8) has
4
been previously described. We followed the reaction by
TLC at 5 min intervals and found darkening and at least
six impurities developing from the beginning and in-
creasing to the end of reaction. We modified the O-
demethylation by heating with 15% HBr in acetic acid,
using conditions similar to those employed by Small for
the conversion of neopine (13, Scheme 2) into neomor-
1
tion. This has taken on heightened significance in recent
2
years with steadily increasing demands on the finite
supply of opium available only through labor-intensive
3
processes. These studies have resulted in efficient routes
for interconversion of many of the drugs and derivatives.
However, in some manufacturing processes, byproducts
of no medical value are produced. One example is
tetrahydrothebaine (1, THT, Scheme 1) produced in the
commercial hydrogenation of thebaine (2, Scheme 2) to
12
phine (14, Scheme 2). Small-scale experiments resulted
in copious evolution of HBr from the reaction mixture
and the separation of crystalline material that was
identified as 6-acetyldihydromorphine hydrobromide (15‚
HBr, Scheme 1). We next studied heating THT (1) in 15%
HBr in acetic acid at 100 °C in a sealed hydrogenation
bottle (under 20 psi) in order to avoid the loss of HBr. As
described below, this gave a 95% yield of chromatographi-
cally homogeneous, analytically pure HBr salt on a 0.1
8
,14-dihydrothebaine (3, Scheme 2) in a process for the
4
production of dihydrocodeinone (4, Scheme 2). Tetrahy-
drothebaine (1) also results from the hydrogenation of
codeine methyl ether (5, Scheme 1), a byproduct of no
medical utility that is produced in the commercial me-
thylation of morphine (6, Scheme 2) to codeine (7, Scheme
4
2
1
). Codeine (7) is the most widely used opiate in U.S.
(5) Rapoport, H.; Naumann, R.; Bissell, E. R.; Bonner, R. M. J . Org.
Chem. 1950, 15, 1103.
medicine and about 90%, or more than 35 000 kg, was
produced by this process in 2001. Thus, THT (1) is
obtained as (or derived from) a byproduct in two impor-
tant manufacturing processes for medical narcotics. Its
recycling to useful medications would be very desirable.
An efficient process for the complete O-demethylation
of THT (1) would provide dihydromorphine (8, DHM,
(
6) Black, T. H.; Forsee, J . C. Synth. Commun. 2000, 30, 3095.
7) Weller, D. D.; Rapoport, H. J . Med. Chem. 1976, 19, 1171-1175.
(
(8) Small, L. F. J . Org. Chem. 1955, 20, 953.
(
9) Small, L. F.; Fitch, H. M.; Smith, W. J . Am. Chem. Soc. 1936,
8, 1457.
10) White, W. C. National Research Council Report of Committee
5
(
on Drug Addiction 1929-1941 and Collected Reprints 1930-1941;
National Academy of Sciences: Washington, DC, 1941. The chemical
research component of this program began in 1929 at the University
of Virginia in Charlottsville under the direction of Dr. Lyndon Small.
It was relocated to the National Institute of Health (then singular) in
1939, and opioid research at NIH has continued to the present. The
contemporary successor to Dr. Small’s group is the Laboratory of
Medicinal Chemistry, NIDDK, NIH, Bethesda, MD, Dr. Kenner C. Rice,
Chief.
†
National Institutes of Health.
Naval Research Laboratory.
1) Casy, A. F.; Parfitt, R. T. Opioid Analgesics. Chemistry and
Receptors; Plenum Press: New York, 1986.
2) Drug Enforcement Administration Production Quota History at
http://www.deadiversion.usdoj.gov/quotas/quota_history.htm.
‡
(
(
(11) May, E. L.; J acobson, A. E. Drug. Alcohol. Depend. 1989, 23,
183-218.
(12) Small, L. F. J . Org. Chem. 1947, 12, 359.
(
(
3) White, P. T.; Raymer, S. Natl. Geographic 1985, 167, 143.
4) Ikonomovski, K. Acta Pharm. J ugosl. 1982, 32, 241.
1
0.1021/jo0206871 This article not subject to U.S. Copyright. Published 2003 American Chemical Society
Published on Web 01/30/2003
2
010 J . Org. Chem. 2003, 68, 2010-2013

SCHEME 1
mol scale merely by filtering and washing. Hydrolysis of
the acetyl group with aqueous NaOH followed by neu-
tralization to pH 9-9.5 followed by filtering and washing
then gave chromatographically and analytically pure
hydrated DHM (8) in 97% yield from its HBr salt and
In summary, we have developed a practical, high-
yielding conversion of THT (1) to DHM (8) that gives an
analytically and chromatographically pure intermediate
and product. This procedure should allow more efficient
production of opium products and be easily modified for
large-scale synthesis. We also described facile conversion
of the readily available codeine to (8S)-8-bromomorphide
(16), a potentially valuable chemical intermediate. The
structure and absolute configuration of 16‚HBr were
determined by X-ray crystallographic analysis.
9
2% yield from THT (1).
We next examined the O-demethylation of dihydroco-
deine (10) that had previously been described with 48%
HBr.13 Upon exposure to 15% HBr in acetic acid as
described for THT (1), 6-acetyldihydromorphine (15)‚HBr
was produced in 94% yield. We also examined the
reaction of codeine methyl ether (5)14 and codeine (7)
under the same conditions used to convert THT (1) to
Exp er im en ta l Section
TLC analyses were carried out on Analtech silica gel GHLF
6
-acetyldihydromorphine (15). In both cases, the product
0.25 mm plates with UV and I
NH OH (80:18:2) as the solvent system. Column chromatography
was carried out with silica gel (ICN SiliTech 32-63, 60 Å), using
CHCl /MeOH/NH OH (100:10:1) as the solvent system. Melting
2 3
detection, using CHCl /MeOH/
was (8S)-8-bromomorphide (16, Scheme 1) hydrobromide
that separated from the reaction mixture in 90% and
4
3
4
9
8% yield, respectively. (8S)-8-Bromomorphide (16) is a
potentially useful intermediate for the synthesis of
-demethoxyoripavine (17, Scheme 2) analogous to bro-
mocodide (18, Scheme 2) in the synthesis of 6-demethoxy-
points were determined in open glass capillaries on a Thomas-
1
Hoover melting-point apparatus and are uncorrected. H NMR
6
spectra were recorded at 300 MHz on a Varian Gemini spec-
trometer in CDCl with tetramethylsilane (TMS) as the internal
3
1
5
standard. Mass spectra (MS) and HRMS were recorded on J EOL
SX 102a. Optical rotations were measured with a Perkin-Elmer
polarimeter 341 using the solvents, concentrations, and wave-
lengths specified. Combustion analyses were performed by
Atlantic Microlabs, Inc., Norcross, GA.
P u r ifica tion of Cr u d e Cr ysta llin e Tetr a h yd r oth eba in e
(1, THT) Hyd r och lor id e. A crude crystalline tetrahydrothe-
baine (1) hydrochloride trihydrate (40 g) mixture, containing
about 7% of neopine methyl ether (12), was obtained from Merck
and Co. in 1947. The mixture was dissolved in 150 mL of water.
To this solution was added 3.1 g of 5% Pd/C. The reaction
mixture was hydrogenated for 1 h at 40 psi and then was filtered
through a pad of Celite. To the yellow solution was added 4 g of
thebaine (19, Scheme 2). A minor impurity produced
in the conversion of codeine (7) to (8S)-8-bromomorphide
(16) was isolated and identified as desoxymorphine C (20,
Scheme 2) that proved identical with an authentic
sample16 from Small’s collection. Our samples of (8S)-8-
bromomorphide (16) were spectroscopically and chro-
matographically identical with an authentic sample17
from Small’s work prepared by the method of Schryver
and Lees.18 X-ray analysis of our sample of (8S)-8-bromo-
morphide (16) then verified the C
determined that the absolute configuration at C
8
bromine position and
was S.19
8
NaOH, and then 0.8 g of NaBH
mixture was stirred for 1 h. The product, tetrahydrothebaine
(1), was extracted with ether and dried over Na SO . The filtrate
4
was added. The reaction
(
13) Horn, J . S.; Paul, A. G.; Rapoport, H. J . Am. Chem. Soc. 1978,
1
00, 1895.
(
(
2
4
14) Barber, R. B.; Rapoport, H. J . Med. Chem. 1975, 18, 1074.
15) Beyerman, H. C.; Crabbendam, P. R.; Lie, T. S.; Maat, L. Recl.
was evaporated and dissolved in 100 mL of a mixture of
Trav. Chim. Pays-Bas 1984, 103, 112.
(
(
16) Small, L. F.; Morris, D. E. J . Am. Chem. Soc. 1933, 55, 2874.
17) Small, L. F.; Yuen, K. C.; Eilers, L. K. J . Am. Chem. Soc. 1933,
(18) Schryver, S. B.; Lees, F. H. J . Chem Soc. 1900, 77, 1024.
(19) Yeh, H. J .; Wilson, R. S.; Klee, W. A.; J acobson, A. E. J . Pharm.
Sci. 1976, 65, 902-904.
5
5, 3863.
J . Org. Chem, Vol. 68, No. 5, 2003 2011

SCHEME 2
2
-propanol/ether (80:20) with the help of a hot water bath or
(13%) of 15‚HBr as a second crop (total yield 39.00 g, 95%). The
salt was converted to free base 15 by heating with aqueous
ultrasound. The addition of 10.5 mL of 36.5% HCl gave 38.9 g
of 1‚HCl‚3H
2
0
2
O salt [mp 112-113 °C (lit. (crystals from acetone)
3 3
NaHCO and extracted with CHCl . The free base was recrystal-
1
2
1
mp 115-116 °C)]. The salt was converted to the free base by
treatment with 1.7 M NaOH (300 mL), and 1 was isolated by
extraction with ether and evaporation of the solvent to give
chromatographically pure 1 (30.5 g, 0.097 mol). Treatment of a
portion of this material with ether gave crystals: mp 80-81 °C
lized from MeOH: mp 241 °C (lit. mp 245 °C); H NMR (free
base) δ 6.68 (d, 1H, J ) 8.1 Hz, H-2), 6.58 (d, 1H, J ) 8.1 Hz,
H-1), δ 5.30 (ddd, 1H, J ) 5.8, 5.5, 2.7 Hz, H-6), 4.63 (d, 1H, J
) 5.8 Hz, H-5), 3.14-3.11 (m, 1H, H-9), 3.01 (d, 1H, J ) 18.6
Hz, H-10R), 2.56 (dd, 1H, J ) 12.3, 3.6 Hz, H-16â), 2.41 (s, 3H,
2
0
(
lit. mp 83 °C). Anal. Calcd for C19
N, 4.44. Found: C, 72.46; H, 7.94; N, 4.39.
-Acetyld ih yd r om or p h in e Hyd r obr om id e (15‚HBr ). (a )
H
25NO
3
: C, 72.35; H, 7.99;
NCH
3
), 2.39 (dd, 1H, J ) 18.6, 5.4 Hz, H-10â), 2.30-2.21 (m,
2H, H-14), 2.30-2.21 (m, 1H, H-16R), 1.89 (dt, 1H, J ) 12.3,
6
4.8 Hz, H-15â), 1.83 (s, 3H, -CH ), 1.72-1.61 (m, 1H, H-8â),
3
F r om Tetr a h yd r oth eba in e (1). A solution of 30% HBr in
acetic acid (150 mL) was added to a solution of tetrahydrothe-
baine (1, 31.50 g, 0.10 mol) in glacial acetic acid (150 mL). The
reaction mixture was stirred for 5 h at 100 °C at 20 psi (in a 1
L hydrogenation bottle, 2002 Ace Glass catalog no. 8648-157;
using a #25 Teflon screw cap, Ace Glass catalog no. 5846-5).
Crystalline material appeared in about 1 h. The mixture was
cooled to room temperature, and ether (400 mL) was added. The
reaction mixture was refrigerated overnight (5 °C). The mixture
was filtered, and the crystals were washed with a mixture of
ether and acetic acid (4:3, 210 mL) until a few drops of the wash
solution diluted with an equal volume water gave a negative
1.72-1.61 (m, 1H, H-15R), 1.53-1.36 (m, 2H, H-7R), 1.53-1.36
(m, 2H, H-7â), 1.09-1.26 (H-8R, m, 1H); MS (FAB) m/z 330 [M
+
+ 1] . Anal. Calcd for C19
H
24BrNO
4
: C, 55.62; H, 5.90; N, 3.41.
1
Found: C, 55.57; H, 5.95; N, 3.33. The H NMR spectrum of 15
base was identical to that of an authentic sample of 6-acetyldihy-
dromorphine (15) originally synthesized from neopine (13) by
Small.12
(b) F r om Dih yd r ocod ein e (10). Dihydrocodeine (10, 1.00
g, 3 mmol), obtained by catalytic reduction of codeine (7) with
Pd/C in MeOH, was dissolved in a mixture of 5 mL of glacial
acetic acid and 5 mL of 30% HBr in acetic acid. The mixture
was treated as shown above for tetrahydrothebaine (1). Com-
pound 15‚HBr (1.15 g) was obtained from 10 in 94% yield.
3
AgNO test, to afford 33.54 g (82%) of chromatographically and
analytically pure 15‚HBr. The filtrate was evaporated to a thick
slurry and filtered, and the collected solid was washed with the
mixture of ether and acetic acid (4:3, 21 mL) to afford 5.46 g
Dih yd r om or p h in e (8)‚1.1H O. 6-Acetyldihydromorphine‚
2
HBr (15‚HBr, 39.00 g, 95 mmol) was dissolved in 10% NaOH
solution (200 mL) and refluxed under nitrogen for 30 min. The
aqueous solution was cooled and adjusted to pH 7 with 36%
hydrochloric acid (25 mL) and then made alkaline (pH 9-9.5)
(20) Sch o¨ pf, C. J ustus Liebigs Ann. Chem. 1927, 452, 411.
2
012 J . Org. Chem., Vol. 68, No. 5, 2003

with NH
4
OH (2 mL). The crystals that formed were washed with
O, 26.36 g, 90%), mp 151-152 °C (lit.12 mp
ice-water (60 mL) and dried in vacuo at 40 °C to give a cream-
colored solid (8‚1.1H
2
1
55-157 °C). The combined filtrate was evaporated to 100 mL,
and 1 mL of NH OH was added to pH 9-9.5. A second crop
4
crystallized and was washed with 10 mL of ice-water. The
crystals were dried under reduced pressure at 40 °C to afford
1
.91 g (6.6%), for a total yield of 97% (28.27 g). The overall yield
of dihydromorphine‚1.1H O (8) from tetrahydrothebaine (1) was
2%. The H NMR spectrum was identical with material
2
1
9
1
2
21 1
synthesized by Small and with the literature: H NMR δ 6.66
(
1
2
d, 1H, J ) 8.0 Hz, H-2), 6.55 (d, 1H, J ) 8.0 Hz, H-1), 4.60 (d,
H, J ) 5.2 Hz, H-5), 4.00 (m, 1H, H-6), 3.13-3.10 (m, 1H, H-9),
.97 (d, 1H, J ) 18.4 Hz, H-10R), 2.56 (dd, 1H, J ) 12.4, 3.8 Hz,
H-16â), 2.41 (s, 3H, -CH ), 2.40 (dd, 1H, J ) 18.4, 6.0 Hz,
3
H-10â), 2.33-2.22 (m, 1H, H-16R), 2.33-2.22 (m, 1H, H-14), 1.93
dt, 1H, J ) 12.4, 5.2 Hz, H-15â), 1.69 (ddd, 1H, J ) 12.4, 3.8,
.9 Hz, H-15R), 1.50-1.41 (m, 3H, H-7R), 1.50-1.41 (m, 3H,
H-7â), 1.50-1.41 (m, 3H, H-8â), 1.12-1.03 (m, 1H, H-8R); MS
(
1
+
(
FAB) m/z 288 [M + 1] . Anal. Calcd for C17
C, 66.47; H, 7.66; N, 4.56. Found: C, 66.44; H, 7.66; N, 4.54.
8S)-8-Br om om or p h id e (16) Hyd r obr om id e fr om Co-
H
21NO
3
‚1.1 H
2
O:
(
F IGURE 1. X-ray of (8S)-8-bromomorphide (16‚HBr) with
d ein e (7) via Cod ein e Meth yl Eth er (5). Codeine methyl
ether (5) was prepared from codeine (7) by the method of Barber
and Rapoport.
displacement parameters at the 20% probability level.
1
4
2
1
.42 (s, 3H, -CH
3
), 2.32 (dt, 1H, J ) 12.1, 3.8 Hz, H-16R), 2.00-
A solution of 30% HBr in acetic acid (5 mL) was added to a
solution of codeine methyl ether (5, 1.00 g, 3.2 mmol) in glacial
acetic acid (5 mL). The procedure was the same as that used for
the preparation of 15‚HBr. The 16‚HBr crystals were obtained
as a gray solid from the reaction mixture (1.24 g, 90%), mp 193-
.87 (m, 2H, H-8R), 1.96 (dt, 1H, J ) 12.4, 5.2 Hz, H-15â), 1.77
(ddd, 1H, J ) 12.4, 3.8, 1.9 Hz, H-15R), 1.52 (m, 1H, H-8â);
+
HRMS (DEI ) m/z 269.1403, C17
2
H19NO requires 269.1416.
Sin gle-cr ysta l X-r a y d iffr a ction a n a lysis of (8S)-8-br o-
+
-
m om or p h id e (16)‚HBr : C17
H
18NO
2
Br Br ‚H
2
O, FW ) 447.17
, a )
1
94 °C. The HBr salt (1.2 g, 2.8 mmol) was converted to the
free base with Na CO solution. Column chromatography of the
crude material using CHCl /MeOH/NH OH (100:10:1) gave a
microcrystalline powder of 16 (0.7 g, 72%). It was recrystallized
-1
(
0.24 × 0.23 × 0.12 mm ), monoclinic space group P2
1
2
3
8
8
.351(1) Å, b ) 11.825(1) Å, c ) 8.946(1) Å, â ) 96.67°, V )
3
-3
3
4
77.41(8) Å , Z ) 2, Fcalc ) 1.69 mg mm , λ(Mo KR) ) 0.710 73
-1
Å, µ ) 4.633 mm , F(000) ) 448, T ) 193 K, R ) 0.027 for
1
from MeOH to give 16‚H
2
O as a crystalline solid: mp 114-115
3
3
1
322 observed (I > 2σI) reflections and 0.030 for the full set of
2
2
0
0
18
°C; [R]
D
+55.8 (c 1, MeOH) [lit. mp 169-170 °C for anhydrous
533 reflections. Data were collected using a Bruker SMART
K CCD detector mounted on a Bruker P4 diffractometer
17
1
6, [R]
D
+65.9 (c 2.8, MeOH)], an authentic anhydrous sample
2
0
from Small’s collection showed [R]
it sintered and darkened at 164 °C; H NMR δ 6.69 (d, 1H, J )
D
1
+61.0 (c 1.1, MeOH) and
equipped with an incident beam monochromator. Corrections
were applied for Lorentz, polarization, and absorption effects.
The structure was solved and refined with the aid of the
8
1
5
1
.0 Hz, H-2), 6.59 (d, 1H, J ) 8.0 Hz, H-1), 6.05 (dd, 1H, J )
0.4, 1.9 Hz H-7R), 5.63 (dt, 1H, J ) 10.4, 2.5 Hz, H-6), 5.05-
.03 (m, 1H, H-5), 4.11 (dd, 1H, J ) 9.9, 1.9 Hz, H-8â), 3.60 (dd,
H, J ) 6.3, 3.0 Hz, H-9), 3.06 (d, 1H, J ) 18.9 Hz, H-10R), 2.75
22
programs in the SHELXTL-plus system of programs. The full-
matrix least-squares refinement on F2 included atomic coordi-
nates and anisotropic thermal parameters for all non-H atoms.
Most of the H atoms were included using a riding model.
Coordinates only were refined for hydrogens on the nitrogen
atom, the hydroxyl oxygen atom and the water molecule. The
absolute configuration was determined experimentally from the
(
1
)
1
dd, 1H, J ) 9.9, 3.0 Hz, H-14), 2.56 (m, 1H, H-16â), 2.46 (dd,
H, J ) 18.9, 6.3 Hz, H-10â), 2.45 (s, 3H,-CH ), 2.30 (dt, 1H, J
12.4, 3.6 Hz, H-16R), 1.96 (dt, 1H, J ) 12.4, 4.9 Hz, H-15â),
.77 (ddd, 1H, J ) 12.6, 3.6, 1.9 Hz, H-15R); MS (FAB) m/z 348
3
+
[M + 1] . Anal. Calcd for C17
H
18BrNO
2
‚H
2
O: C, 57.15; H, 5.36;
23
anomalous scattering of the bromine atoms. Atomic coordinates
N, 3.91. Found: C, 57.39; H, 5.25; N, 3.93. A sample of 16‚HBr,
have been deposited with the Cambridge Crystallographic
Data Base, 12 Union Road, Cambridge CB2 1EZ, UK (deposit@
ccdc.cam.ac.uk).
crystallized slowly from methanol in a diethyl ether atmosphere
(
mp 197-198 °C), was used for X-ray structure analysis to
unequivocally determine its structure (Figure 1). The hydrate
1
7
1
6‚H
using TLC, MS, and H NMR.
8S)-8-Br om om or p h id e (16) H yd r ob r om id e fr om
Cod ein e‚H O (7). A solution of 30% HBr in acetic acid (7.5 mL)
was added to a solution of codeine‚H O (3, 1.58 g, 5 mmol) in
2
O was found to be identical with an authentic sample
Ack n ow led gm en t. We (LMC, NIDDK) thank the
National Institute on Drug Abuse, NIH, for partial
financial support of our research program. We also
thank Noel Whitaker and Victor Livengood (NIDDK,
NIH) for mass spectral analysis. The X-ray crystal-
lographic work was supported by the Office of Naval
Research and, in part, by the National Institute on Drug
Abuse, NIH.
1
19
(
2
2
glacial acetic acid (7.5 mL). The procedure was the same as that
used for the preparation of 15‚HBr. The 16‚HBr crystals from
the reaction mixture were obtained as a white solid (2.10 g, 98%).
TLC of the crude material showed 2 minor impurities at R
and 0.55. The impurity of R 0.55 was isolated by column
chromatography with solvent: CHCl /MeOH/NH OH (100:10:
). It was identified as desoxymorphine C (20, Scheme 2), which
f
0.26
f
3
4
Su p p or tin g In for m a tion Ava ila ble: Details of the X-ray
structure of (8S)-8-bromomorphide‚HBr (16‚HBr), including
tables of crystal data, atomic coordinates, bond lengths and
angles, positional and anisotropic thermal parameters. This
material is available free of charge via the Internet at
http://pubs.acs.org.
1
1
6
was found to be identical with Small’s sample using TLC, MS,
and H NMR. Free base 20 was crystallized from ethyl acetate:
1
1
6
1
mp 192-193 °C (lit. mp 189-190 °C); H NMR δ 6.65 (d, 1H,
J ) 8.0 Hz, H-2), 6.56 (d, 1H, J ) 8.0 Hz, H-1), 5.83 (m, 1H,
H-6), 5.63 (m, 1H, H-7), 4.92 (s, 1H, H-5), 3.18 (dd, 1H, J ) 6.0,
2
.7 Hz, H-9), 3.01 (d, 1H, J ) 18.4 Hz, H-10R), 2.63 (m, 1H,
J O0206871
H-16â), 2.53-2.44 (m, 2H, H-10â), 2.53-2.35 (m, 2 H, H-14),
(
22) Sheldrick, G. M. 1997 SHELXTL-plus, Version 5.1; Bruker
(21) Crouch, R. C.; Bhatia, A. V.; Lever, O. W., J r. J . Heterocycl.
Analytical X-ray Instruments: Madison, WI.
Chem. 1990, 27, 385-389.
(23) Flack, H. D. Acta Crystallogr. 1983, A39, 876-881.
J . Org. Chem, Vol. 68, No. 5, 2003 2013