GB2444052A - Processes of preparing morphinan derivatives such as naltrexone and naloxone comprising O- and N-demethylation and reductive alkylation steps - Google Patents
Processes of preparing morphinan derivatives such as naltrexone and naloxone comprising O- and N-demethylation and reductive alkylation steps Download PDFInfo
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- GB2444052A GB2444052A GB0610385A GB0610385A GB2444052A GB 2444052 A GB2444052 A GB 2444052A GB 0610385 A GB0610385 A GB 0610385A GB 0610385 A GB0610385 A GB 0610385A GB 2444052 A GB2444052 A GB 2444052A
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- demethylation
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- 238000010520 demethylation reaction Methods 0.000 title claims abstract description 30
- 238000000034 method Methods 0.000 title claims abstract description 25
- 229960003086 naltrexone Drugs 0.000 title claims abstract description 12
- DQCKKXVULJGBQN-XFWGSAIBSA-N naltrexone Chemical compound N1([C@@H]2CC3=CC=C(C=4O[C@@H]5[C@](C3=4)([C@]2(CCC5=O)O)CC1)O)CC1CC1 DQCKKXVULJGBQN-XFWGSAIBSA-N 0.000 title claims abstract description 12
- 229960004127 naloxone Drugs 0.000 title claims abstract description 10
- UZHSEJADLWPNLE-GRGSLBFTSA-N naloxone Chemical compound O=C([C@@H]1O2)CC[C@@]3(O)[C@H]4CC5=CC=C(O)C2=C5[C@@]13CCN4CC=C UZHSEJADLWPNLE-GRGSLBFTSA-N 0.000 title claims abstract description 10
- INAXVFBXDYWQFN-XHSDSOJGSA-N morphinan Chemical class C1C2=CC=CC=C2[C@]23CCCC[C@H]3[C@@H]1NCC2 INAXVFBXDYWQFN-XHSDSOJGSA-N 0.000 title description 3
- 229940051807 opiod analgesics morphinan derivative Drugs 0.000 title 1
- 238000005932 reductive alkylation reaction Methods 0.000 title 1
- 150000001875 compounds Chemical class 0.000 claims abstract description 34
- 238000006243 chemical reaction Methods 0.000 claims abstract description 29
- -1 alkyl chloroformate Chemical compound 0.000 claims abstract description 19
- ILAHWRKJUDSMFH-UHFFFAOYSA-N boron tribromide Chemical compound BrB(Br)Br ILAHWRKJUDSMFH-UHFFFAOYSA-N 0.000 claims abstract description 14
- 150000003839 salts Chemical class 0.000 claims abstract description 7
- QOPVNWQGBQYBBP-UHFFFAOYSA-N chloroethyl chloroformate Chemical compound CC(Cl)OC(Cl)=O QOPVNWQGBQYBBP-UHFFFAOYSA-N 0.000 claims abstract description 6
- 230000002829 reductive effect Effects 0.000 claims abstract description 6
- 229910015845 BBr3 Inorganic materials 0.000 claims abstract description 5
- 238000002360 preparation method Methods 0.000 claims abstract description 5
- 125000001559 cyclopropyl group Chemical group [H]C1([H])C([H])([H])C1([H])* 0.000 claims abstract description 3
- BEOOHQFXGBMRKU-UHFFFAOYSA-N sodium cyanoborohydride Chemical compound [Na+].[B-]C#N BEOOHQFXGBMRKU-UHFFFAOYSA-N 0.000 claims abstract description 3
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 claims abstract description 3
- 230000007062 hydrolysis Effects 0.000 claims abstract 5
- 238000006460 hydrolysis reaction Methods 0.000 claims abstract 5
- 125000003118 aryl group Chemical group 0.000 claims abstract 3
- 125000002485 formyl group Chemical class [H]C(*)=O 0.000 claims abstract 2
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 claims description 41
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 claims description 15
- 239000003153 chemical reaction reagent Substances 0.000 claims description 15
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 12
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 12
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 claims description 12
- 239000002904 solvent Substances 0.000 claims description 11
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 8
- 229910052744 lithium Inorganic materials 0.000 claims description 8
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 claims description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 5
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 claims description 4
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims description 4
- 230000000994 depressogenic effect Effects 0.000 claims description 4
- 125000000468 ketone group Chemical group 0.000 claims description 4
- RIFGWPKJUGCATF-UHFFFAOYSA-N ethyl chloroformate Chemical compound CCOC(Cl)=O RIFGWPKJUGCATF-UHFFFAOYSA-N 0.000 claims description 2
- 150000002500 ions Chemical class 0.000 claims description 2
- 239000007810 chemical reaction solvent Substances 0.000 claims 1
- 239000007858 starting material Substances 0.000 abstract description 3
- BRUQQQPBMZOVGD-XFKAJCMBSA-N Oxycodone Chemical compound O=C([C@@H]1O2)CC[C@@]3(O)[C@H]4CC5=CC=C(OC)C2=C5[C@@]13CCN4C BRUQQQPBMZOVGD-XFKAJCMBSA-N 0.000 abstract description 2
- 150000007976 iminium ions Chemical class 0.000 abstract description 2
- 229960002085 oxycodone Drugs 0.000 abstract description 2
- 239000011541 reaction mixture Substances 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 239000008346 aqueous phase Substances 0.000 description 6
- FZFAMSAMCHXGEF-UHFFFAOYSA-N chloro formate Chemical compound ClOC=O FZFAMSAMCHXGEF-UHFFFAOYSA-N 0.000 description 5
- 238000004128 high performance liquid chromatography Methods 0.000 description 5
- 239000000543 intermediate Substances 0.000 description 5
- KXDHJXZQYSOELW-UHFFFAOYSA-M Carbamate Chemical compound NC([O-])=O KXDHJXZQYSOELW-UHFFFAOYSA-M 0.000 description 4
- HLMSIZPQBSYUNL-IPOQPSJVSA-N Noroxymorphone Chemical compound O=C([C@@H]1O2)CC[C@@]3(O)[C@H]4CC5=CC=C(O)C2=C5[C@@]13CCN4 HLMSIZPQBSYUNL-IPOQPSJVSA-N 0.000 description 4
- 239000003638 chemical reducing agent Substances 0.000 description 4
- 239000005457 ice water Substances 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- WSLDOOZREJYCGB-UHFFFAOYSA-N 1,2-Dichloroethane Chemical compound ClCCCl WSLDOOZREJYCGB-UHFFFAOYSA-N 0.000 description 3
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 3
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 3
- 239000007832 Na2SO4 Substances 0.000 description 3
- RIKMCJUNPCRFMW-ISWURRPUSA-N Noroxycodone Chemical compound O=C([C@@H]1O2)CC[C@@]3(O)[C@H]4CC5=CC=C(OC)C2=C5[C@@]13CCN4 RIKMCJUNPCRFMW-ISWURRPUSA-N 0.000 description 3
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 3
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 150000001299 aldehydes Chemical class 0.000 description 3
- 235000011114 ammonium hydroxide Nutrition 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 239000012074 organic phase Substances 0.000 description 3
- 238000010992 reflux Methods 0.000 description 3
- 229910052938 sodium sulfate Inorganic materials 0.000 description 3
- 235000011152 sodium sulphate Nutrition 0.000 description 3
- 239000012321 sodium triacetoxyborohydride Substances 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- RSSHKMSIEMOBQX-KFIKYVJASA-N (4r,4as,7ar,12bs)-4a-hydroxy-9-methoxy-3-methyl-2,4,5,6,7a,13-hexahydro-1h-4,12-methanobenzofuro[3,2-e]isoquinoline-7-one Chemical compound O=C([C@@H]1O2)CC[C@@]3(O)[C@H]4CC5=CC=C(OC)C2=C5[C@@]13CCN4C.O=C([C@@H]1O2)CC[C@@]3(O)[C@H]4CC5=CC=C(OC)C2=C5[C@@]13CCN4C RSSHKMSIEMOBQX-KFIKYVJASA-N 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 description 2
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 2
- 239000000010 aprotic solvent Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000284 extract Substances 0.000 description 2
- 239000000706 filtrate Substances 0.000 description 2
- 230000003301 hydrolyzing effect Effects 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000006722 reduction reaction Methods 0.000 description 2
- ILJKKAIQFPEIBL-UHFFFAOYSA-N 2-cyclopropyl-2-hydroxyacetonitrile Chemical compound N#CC(O)C1CC1 ILJKKAIQFPEIBL-UHFFFAOYSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 1
- USQOVYLRWBOSQC-HNNXBMFYSA-N CCCCCCNC(=O)Oc1cccc(c1)-c1ccc(cc1F)[C@H](C)C(O)=O Chemical compound CCCCCCNC(=O)Oc1cccc(c1)-c1ccc(cc1F)[C@H](C)C(O)=O USQOVYLRWBOSQC-HNNXBMFYSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 239000012448 Lithium borohydride Substances 0.000 description 1
- WJBLNOPPDWQMCH-MBPVOVBZSA-N Nalmefene Chemical compound N1([C@@H]2CC3=CC=C(C=4O[C@@H]5[C@](C3=4)([C@]2(CCC5=C)O)CC1)O)CC1CC1 WJBLNOPPDWQMCH-MBPVOVBZSA-N 0.000 description 1
- UIQMVEYFGZJHCZ-SSTWWWIQSA-N Nalorphine Chemical compound C([C@@H](N(CC1)CC=C)[C@@H]2C=C[C@@H]3O)C4=CC=C(O)C5=C4[C@@]21[C@H]3O5 UIQMVEYFGZJHCZ-SSTWWWIQSA-N 0.000 description 1
- UQCNKQCJZOAFTQ-ISWURRPUSA-N Oxymorphone Chemical compound O([C@H]1C(CC[C@]23O)=O)C4=C5[C@@]12CCN(C)[C@@H]3CC5=CC=C4O UQCNKQCJZOAFTQ-ISWURRPUSA-N 0.000 description 1
- JFBZPFYRPYOZCQ-UHFFFAOYSA-N [Li].[Al] Chemical compound [Li].[Al] JFBZPFYRPYOZCQ-UHFFFAOYSA-N 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 239000000908 ammonium hydroxide Substances 0.000 description 1
- 230000000202 analgesic effect Effects 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 150000004657 carbamic acid derivatives Chemical class 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- JMYVMOUINOAAPA-UHFFFAOYSA-N cyclopropanecarbaldehyde Chemical compound O=CC1CC1 JMYVMOUINOAAPA-UHFFFAOYSA-N 0.000 description 1
- 238000010511 deprotection reaction Methods 0.000 description 1
- 229960004132 diethyl ether Drugs 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 239000012458 free base Substances 0.000 description 1
- 238000004108 freeze drying Methods 0.000 description 1
- 150000004678 hydrides Chemical class 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000002808 molecular sieve Substances 0.000 description 1
- 229960005297 nalmefene Drugs 0.000 description 1
- 229960000938 nalorphine Drugs 0.000 description 1
- 239000003887 narcotic antagonist Substances 0.000 description 1
- 125000004433 nitrogen atom Chemical group N* 0.000 description 1
- 229960005118 oxymorphone Drugs 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- RGSFGYAAUTVSQA-UHFFFAOYSA-N pentamethylene Natural products C1CCCC1 RGSFGYAAUTVSQA-UHFFFAOYSA-N 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- AHWALFGBDFAJAI-UHFFFAOYSA-N phenyl carbonochloridate Chemical group ClC(=O)OC1=CC=CC=C1 AHWALFGBDFAJAI-UHFFFAOYSA-N 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000006268 reductive amination reaction Methods 0.000 description 1
- 150000003335 secondary amines Chemical class 0.000 description 1
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 description 1
- 235000017557 sodium bicarbonate Nutrition 0.000 description 1
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 235000017550 sodium carbonate Nutrition 0.000 description 1
- 125000001424 substituent group Chemical group 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D489/00—Heterocyclic compounds containing 4aH-8, 9 c- Iminoethano-phenanthro [4, 5-b, c, d] furan ring systems, e.g. derivatives of [4, 5-epoxy]-morphinan of the formula:
- C07D489/06—Heterocyclic compounds containing 4aH-8, 9 c- Iminoethano-phenanthro [4, 5-b, c, d] furan ring systems, e.g. derivatives of [4, 5-epoxy]-morphinan of the formula: with a hetero atom directly attached in position 14
- C07D489/08—Oxygen atom
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
Abstract
A process for the preparation of a compound of formula (V), or salt thereof, comprises O-and N-demethylation of a compound of formula (I) followed by reaction of the product with an aldehyde RCHO to produce an intermediate containing an iminium ion which is reduced to give a compound of formula (I). X is O, CH2 or is a diC1-6alkoxy group and R is a cyclopropyl or vinyl group. Where X is a diC1-6alkoxy group, this may be removed to yield a compound of formula (V) wherein X is O. In particular, the compound of formula (V) is naltrexone or naloxone and the starting material of formula (I) is oxycodone. The O- and N-demethylation may be carried out with an aryl or alkyl chloroformate, especially a-chloroethylchloroformate, followed by hydrolysis of the resulting intermediate, e.g. with lithium tri-sec-butylborohydride or the O-demethylation may be carried out with BBr3. The reduction of the iminium-containing intermediate may be carried out with sodium triacetylborohydride or sodium cyanoborohydride. <EMI ID=1.1 HE=131 WI=83 LX=755 LY=1426 TI=CF>
Description
CHEMICAL PROCESS
The present invention relates to a process for the preparation of naltrexone or naloxone.
It has been known for over 30 years that when suitable substituents are introduced on the nitrogen atom of a morphinan derivative, the resulting compounds are narcotic antagonists that may also have analgesic properties and are not addictive.
Some commercial and well known morphinans are shown below. These include naltrexone and naloxone.
HO
NALTREXONE HO NALMEFENE
H H N HO"
NALBUPI-UNE
HO
NALOXONE NALORPHINE
Numerous reaction sequences are known for the preparation of naltrexone and naloxone but these generally involve numerous steps and can lead to low overall yields. It is still desirable to find a method of producing naltrexone and naloxone which can start from readily commercially available compounds and lead to good yields of naltrexone and naloxone by processes that do not involve * * S * . * * S * S * S S S * * S S S *S * S *e* * * * * S * : * * * S *** . :..
too many individual reactions. A reaction sequence that commences from optionally protected oxycodone and leads to the desired compounds in an effective manner is now provided. The route employed offers the potential advantage of requiring fewer steps.
Therefore, the invention provides a process for the preparation of naltrexone or naloxone or a salt thereof which process comprises: a) the reaction of a compound of the formula (I): H3CO / NCH3 X (I) or a salt thereof wherein X is O,CH2 or X= is a diC16alkoxy group, with a reagent or reagents which result in 0-and N-demethylation to provide a compound of the formula (II):
NH
OH
X (II) or a salt thereof; followed by: * * * * * * * * * * * * S I S * S S S ** S S *SS S S S * I S 5 * * S S S. * S * 5 S *I* b) the reaction with an aldehyde of the formula (Ill): R-CHO (III) wherein R is a cyclopropyl or vinyl group, to yield a intermediate containing the ion of the formula (IV): HO7
NCH-R
)!=.!=J' * OH X (IV) which is reduced to yield a compound of the formula (V): /s> N-CH2R
OH X (V)
wherein X is 0, CH2 or X= is a diC16alkoxy group and removing the keto protecting group if present to yield a compound wherein X is 0.
Most aptly X is 0 or OCH2CH2O. Preferably X is 0. * * *
* S S * * * * S * * S * * S S S ** * * *. : * * * * * S S S * S. 5. S I * 15* The conversion of compound of formula (I) into the compound of formula (II) may be effected in one or two steps.
Thus, for example, the compound of formula (I) may be reacted with a reagent which results in 0-demethylation followed by reaction with a reagent which results in N-demethylation. Alternatively, the compound of formula (I) may be reacted with a reagent which results in Ndemethylation followed by reaction with a reagent which results in 0-demethylation. In one aspect the reagent employed effects both 0-demethylation and N-demethylation.
In some methods of N-demethylation an intermediate carbamate is formed (for example from reaction with a chloroformate) which is then cleaved, for example by the use of L-selectride.
If the chioroformate used is a-chloroethylchloroformate (ACE-Cl), the carbamate formed will be easily hydrolysed. Weak hydrolysing agents, such as MeOH may be used to hydrolyse these carbamates.
If the chloroformate used is C2..6chloroformate, for example ethylchloroformate, the carbamate intermediate will be more stable. A suitable hydrolysing agent that can be used is Lithium selectride (lithium tri-sec-butylborohydride). Another example of a chloroformate is phenyl chloroformate.
A suitable reagent of use in the 0-demethylation and N-deprotection of carbamate intermediates of the compound of the formula (I) is lithium selectride.
An apt reagent for use for the 0-demethylation of a compound of formula (I) is BBr3. An apt reagent for use for the N-demethylation of a compound of formula (I) is a chloroformate, for example a-chloroC1..6alkylchloroformate, preferably a-chioroethylchloroformate. A suitable reagent for use in the 0-demethylation and N-demethylation (via a decarboxymethylation) of a compound of formula (I) is lithium selectride (tri-sec-butylborohyd ride). * S *
* S * * * * I * * * I S * *** I I I ** I * * S I S I S * * S S ** S ** I S I * SIt The reaction of the compound of formula (I) (or its N-demethylated analogue) with BBr3 may take place in an aprotic solvent such as tetrahydrofuran, chloroform, methylene dichloride, 1, 2-dichloroethane or the like. Addition of BBr3 generally takes place at a depressed temperature for example 0 C.
Generally, ambient temperature, for example 20-30 C, is thereafter employed.
After the reaction is complete, which generally takes from 2 to 4 hours, it is quenched by using water containing a base such as ammonium hydroxide, preferably at a depressed temperature, for example by using ice. The desired compound of formula (II) may be obtained from the aqueous phase (whereas the N-methylated analogue of the compound of formula (II) may be obtained form the organic phase).
The reaction of a compound of formula (I) (or its 0-demethyl analogue) with a chloroformate such as ci-chioroethyichioroformate may be employed to effect N-demethylation.
The N-demethylation of a compound of formula (I) (or its 0-demethylated analogue) into a compound of the formula (II) may be effected at non-extreme elevated temperature, for example at the reflux point of the solvent employed or at about 30-70 C, for example 40-50 C.
The solvent employed may be carried out in a solvent such as tetrahydrofuran, acetonitrile, dimethylformamide, dichioromethane, I,2-dichloroethane or the like. A favoured solvent is dichioromethane. Surprisingly a most preferably solvent is acetonitrile.
Generally, the reaction is performed under anhydrous conditions, for example under nitrogen. The reaction generally employs a proton abstracting agent, for example carbonate or bicarbonate. Anhydrous sodium carbonate is particularly apt. * . *
* a a * * * * * * a I * * *** S * * S. a * * S * * S * * * * * S S. $ ** S * * * a..
The compound of the formula (I), preferably wherein X is a protected keto group, may be N-demethylated or both N-demethylated and 0-demethylated by reaction with lithium trialkylborohydride following reaction with ACE-Cl.
Suitable lithium trialkylborohydrides include lithium triethylborohydride, lithium tripropylborohydride, lithium tributylborohydride or lithium tripentylborohydride.
A preferred reagent is lithium tri-sec-butylborohydride (sometimes referred to as lithium selectride).
The reaction is carried out in an aprotic solvent such as tetrahydrofuran, diethylether, toluene, dichloromethane, acetonitrile or the like. A non-extreme temperature is generally employed, for example from ambient temperature (about 20-25 C) or an elevated temperature of 50-70 C, for example at reflux.
N-demethylation (via N-decarboxymethylation) may occur first. If the reaction is allowed to proceed, 0-demethylation can then occur to yield the N,O-didemethylated product of the formula (II).
The compound of the formula (II) may be converted to a compound of the formula (V) by reaction with an aldehyde (RCHO) and reduction of the intermediate iminium ion with a suitable reducing agent.
When the 6-keto function is protected, standard hydride reducing agents may be employed. Suitable reducing agents include lithium aluminium hydrides and alkali metal borohydrides. When the 6-keto function is not protected, milder reducing agents are required, for example a triacetylborohyd ride such as lithium or sodium triacetoxyborohydride, sodium cyanoborohydride or even hydrogen gas with a catalyst such as palladium. A preferred reagent is sodium triacetoxyborohydride.
The reductive amination reaction is preferably carried out in a solvent such as tetrahydrofuran, dimethylformamide, dimethylsulfoxide, dichloromethane, 1,2- dichloroethane, ethanol, isopropanol or the like. A preferred solvent is 1,2-dichloroethane.
a a S * S * * S S * * * * I * : : : ** : : : * * *** 5.1:..
The initial reaction between the aldehyde and secondary amine may take place at ambient temperature, for example 20-25C , optionally in the presence of molecular sieves and preferably under anhydrous conditions.
Generally, when X is 0, the reduction reaction is carried out at a depressed temperature, for example -20 C to -30 C. When X is a keto protecting group higher temperatures, for example 0-25 C may be employed.
The compound of formula (II) may be obtained from solution by freeze drying if desired.
Example I
0-demethylation of oxycodone Oxycodone HCI (3.04 g, 8.66 mmol) was suspended in DCM (30 ml) under nitrogen and the reaction flask was immersed in an ice-water bath. Boron tribromide (-3 eq, 25 ml of a I M solution in DCM) was added slowly with stirring. The reaction flask was left in the ice-water bath and the temperature rose slowly to room temperature (RT). Stirring at RT was continued overnight after which HPLC indicated full conversion of starting material. Water (25 ml) was added and the bi-phased reaction mixture was refluxed for 1 hour. The reaction mixture was allowed to cool slowly to RT and a white crystalline solid formed. The solid was filtered off and the resulting filtrate was basified (NH4OH, pH 10). The organic and aqueous phases were separated and the aqueous phase was extracted 5 times using DCM. The combined organic extracts were dried (Na2SO4), filtered and the solvent was removed under reduced pressure.
The residue was dried under vacuum overnight to yield crude oxymorphone as a beige solid 2.34 g (90 % yield), purity <96 % by HPLC.
Example 2
0-Demethylation of noroxycodone Noroxycodone (0.20 g, 0.66 mmol) was suspended in DCM (3 ml) under nitrogen and the reaction flask was immersed in an ice-water bath. Boron tribromide (--3 eq, 2 ml of a 1 M solution in DCM) was added slowly with stirring.
* 0 0 * .0 * * * . 0 * * * * * : : : *. : : : ** 0* * * * 0 * * * *.* The reaction flask was left in the ice-water bath and stirring continued while the temperature rose slowly to RT, after which HPLC showed that all of the starting material had been consumed. Water (3 ml) was added and the reaction mixture was refluxed for 7 hours. The reaction mixture was basified (NH4OH, pH 10) and extracted 4 times with DCM. The product remained in the aqueous phase.
Example 3
N-Demethylation of Oxycodone Oxycodone free base (1.19 g)was dissolved in 6 ml DCM and Na2CO3 (1.60 g) was added. ACE-Cl (1.56m1) was added drop wise to the stirred suspension at RT, and the reaction mixture was heated to reflux and stirred for 24 hours. The reaction mixture was filtered and the precipitate was washed with DCM. The filtrate was evaporated to dryness. MeOH (20 ml) was added and the mixture stirred for 1 h at RT. The solution was again evaporated to dryness and added water (25 ml) and conc. HCI (1 ml). The aqueous phase was washed twice with DCM and then added ammonia until pH 11. The aqueous phase was extracted five times with DCM:MeOH (80:20). The combined organic extracts were dried (Na2SO4), filtered and the solvent was removed under reduced pressure. Crude noroxycodone was obtained as a white foam (0.73 g, 64%), purity 90 % by HPLC.
Example 4
N-cyclopropylmethylation of noroxymorphone Noroxymorphone (0.lOOg) and cyclopropylcarboxaldehyde (0.023 g) are mixed in dichloromethane at room temperature. Also after 30 minutes the solution is cooled to -30 C and NaBH(OAc)3 added. This reaction is left for two days.
HPLC is used to show the presence of naltrexone.
Example 5
N-cyclopropylmethylation of noroxymorphone Noroxymorphone (0.lg) and cyclopropanecarboxaldehyde (0.023g) are mixed in dichoromethane 20m1) at room temperature for 30 minutes. The solution is cooled to -30 C and sodium triacetoxyborohydride (0.07g) is added. The reaction mixture is quenched with sodium bicarbonate solution (20m1) and the * 0 * * *0. a * * I I S * S I * S. * S * S S S I * : : . S.. * **.
phases separated. The solution is adjusted to neutrality. The organic phase is dried (Na2SO4), is filtered and the solvent is removed under reduced pressure to yield naltrexone.
* I * * * * * I I * : : : . :1: : . *t * *** . . . * ***
Claims (16)
- Claims 1. A process for the preparation of naltrexone or naloxone or asalt thereof which process comprises: a) the reaction of a compound of the formula (I): H3co /J NCH3 X (I) or a salt thereof wherein X is O,CH2 or X= is a diC1..6alkoxy group, with a reagent or reagents which result in 0-and N-demethylation to provide a compound of the formula (II):NHOHX (II) or a salt thereof; followed by: the reaction with an aldehyde of the formula (Ill): I I * * . I * * * * : * * * as a a * * * a a * I a * a a * ** * *.: * * *IR-CHO (Ill) wherein R is a cyclopropyl or vinyl group, to yield an intermediate containing the ion of the formula (IV): /JNCH-R )J'$OHX (IV) which is reduced to yield a compound of the formula (V):HON-CH2R X (V) wherein X is 0, CH2 or X= is a diC16alkoxy group and removing the keto protecting group if present to yield a compound wherein X is 0.
- 2. A process as claimed in claim I wherein X is OCH2CH2O.
- 3. A process as claimed in claim I wherein X is 0. * ** *
- 4 * * S * * * I I a a * I * SI I * ** ** S a S * a * I I a ** * *.: * * * 4. A process as claimed in any of claims I to 3 wherein the 0-demethylation is effected using BBr3.
- 5. A process as claimed in any of claims I to 3 where the N-demethylation and 0-demethylation is effected using an aryl or alkyl chloroformate, preferably using a-chloroethylchloroformate, followed by hydrolysis of the resulting intermediate, preferably using lithium tri-sec-butylborohyd ride.
- 6. A process as claimed in any of claims I to 4 where the N-demethylation is effected using an aryl or alkyl chloroformate followed by hydrolysis of the resulting intermediate.
- 7. A process as claimed in claim 6 which employs a-chloroalkyl chloroformate, preferably a-chloroC1..6chloroformate.
- 8. A process as claimed in claim 7 wherein the a-chloroC1.6chloroformate is ci-chloroethylchloroformate.
- 9. A process as claimed in claim 8 wherein the hydrolysis is effected using an alcohol such as methanol or lithium tri-sec-butylborohydride.
- 10. A process as claimed in claim 6 which employs a C2..6chloroformate, for example ethylchloroformate.
- 11. A process as claimed in claim 10 wherein the hydrolysis is effected using lithium tri-sec-butylborohydride.
- 12. A process as claimed in any preceding claim wherein the reaction solvent in the N-demethylation and 0-demethylation reaction is selected from tetrahydrofu ran, aceton itrile, dimethylformamide, dichloromethane or 1,2-d ichloroethane, preferably d ichloromethane or acetonitrile. ** S S S * * * S * * * S S S 5 * * * S. S 5 * * S 5 5 * S S * * S S * S. 4 *** * . * * *S.
- 13. A process as claimed in any of claims I to 12 wherein the reduction is effected employing a triacetylborohydride such as sodium triacetylborohydride.
- 14. A process as claimed in any of claims I to 12 wherein the reduction is effected by employing a cyanoborohydride such as sodium cyanoborohydride.
- 15. A process as claimed in claims 13 or 14 performed at a depressed temperature, for example 5 C to -30 C.
- 16. A process as claimed in any preceding claim wherein the reduction is carried out in a solvent such as tetrahydrofuran, dimethylformamide, dimethylsulfoxide, dichloromethane, I,2-dichloroethane, ethanol and isopropanol, preferably I,2-d ichloroethane. S ** * S * S * .: : : : *:. * : : * 4 0 * * I S * * *.S * * I * SOS
Priority Applications (7)
Application Number | Priority Date | Filing Date | Title |
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GB1017991A GB2471803B (en) | 2006-05-25 | 2006-05-25 | Chemical process |
GB0610385A GB2444052A (en) | 2006-05-25 | 2006-05-25 | Processes of preparing morphinan derivatives such as naltrexone and naloxone comprising O- and N-demethylation and reductive alkylation steps |
PCT/EP2007/004679 WO2007137785A2 (en) | 2006-05-25 | 2007-05-25 | Process useful in the preparation of morphinan antagonists |
US12/300,055 US20100022774A1 (en) | 2006-05-25 | 2007-05-25 | Process useful in the preparation of morphinan antagonists |
EP07725575A EP2032579A2 (en) | 2006-05-25 | 2007-05-25 | Process useful in the preparation of morphinan antagonists |
AU2007267362A AU2007267362B2 (en) | 2006-05-25 | 2007-05-25 | Process useful in the preparation of morphinan antagonists |
CA002652849A CA2652849A1 (en) | 2006-05-25 | 2007-05-25 | Process useful in the preparation of morphinan antagonists |
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GB0610385A GB2444052A (en) | 2006-05-25 | 2006-05-25 | Processes of preparing morphinan derivatives such as naltrexone and naloxone comprising O- and N-demethylation and reductive alkylation steps |
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GB0610385A Withdrawn GB2444052A (en) | 2006-05-25 | 2006-05-25 | Processes of preparing morphinan derivatives such as naltrexone and naloxone comprising O- and N-demethylation and reductive alkylation steps |
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WO2019009820A1 (en) * | 2017-07-04 | 2019-01-10 | Saneca Pharmaceuticals A.S. | Process for the preparation of morphinane compounds |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3717643A (en) * | 1967-05-04 | 1973-02-20 | Sterling Drug Inc | N-substituted-norapomorphines |
US3905981A (en) * | 1973-10-12 | 1975-09-16 | Research Corp | N-dealkylation of tertiary amines |
GB2000137A (en) * | 1977-06-21 | 1979-01-04 | Warner Lambert Co | 7,8-Dihydro-14-hydroxy-normorphine |
EP0164290A1 (en) * | 1984-05-25 | 1985-12-11 | Sanofi S.A. | Process for the dealkylation of alcaloids and intermediates |
WO2006035195A1 (en) * | 2004-09-30 | 2006-04-06 | Johnson Matthey Public Limited Company | Preparation of opiate analgesics by reductive alkylation |
-
2006
- 2006-05-25 GB GB1017991A patent/GB2471803B/en not_active Expired - Fee Related
- 2006-05-25 GB GB0610385A patent/GB2444052A/en not_active Withdrawn
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3717643A (en) * | 1967-05-04 | 1973-02-20 | Sterling Drug Inc | N-substituted-norapomorphines |
US3905981A (en) * | 1973-10-12 | 1975-09-16 | Research Corp | N-dealkylation of tertiary amines |
GB2000137A (en) * | 1977-06-21 | 1979-01-04 | Warner Lambert Co | 7,8-Dihydro-14-hydroxy-normorphine |
EP0164290A1 (en) * | 1984-05-25 | 1985-12-11 | Sanofi S.A. | Process for the dealkylation of alcaloids and intermediates |
WO2006035195A1 (en) * | 2004-09-30 | 2006-04-06 | Johnson Matthey Public Limited Company | Preparation of opiate analgesics by reductive alkylation |
Non-Patent Citations (5)
Title |
---|
Journal of Medicinal Chemistry Vol. 21, No. 4, 1978, pages 398-400 * |
Journal of Organic Chemistry Vol. 49, No. 11, 1984, pages 2081-2082 * |
Tetrahedron Vol., 48, No. 32, 1992, pages 6709-6716 * |
Yaoxue Xuebao Vol. 17, No. 7, 1982, pages 546-548 * |
Zhongguo Yaowu Huaxue Zazhi Vol. 8, No. 2, 1998, pages 141-146 * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2019009820A1 (en) * | 2017-07-04 | 2019-01-10 | Saneca Pharmaceuticals A.S. | Process for the preparation of morphinane compounds |
CN110770237A (en) * | 2017-07-04 | 2020-02-07 | 萨内卡制药公司 | Process for the preparation of morphinan compounds |
EA039283B1 (en) * | 2017-07-04 | 2021-12-28 | Санека Фармасьютикалс А.С. | Process for the preparation of morphinane compounds |
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GB0610385D0 (en) | 2006-07-05 |
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GB201017991D0 (en) | 2010-12-08 |
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