WO1999007721A1 - Improved process for antiparasitic agent - Google Patents

Improved process for antiparasitic agent Download PDF

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Publication number
WO1999007721A1
WO1999007721A1 PCT/EP1998/004931 EP9804931W WO9907721A1 WO 1999007721 A1 WO1999007721 A1 WO 1999007721A1 EP 9804931 W EP9804931 W EP 9804931W WO 9907721 A1 WO9907721 A1 WO 9907721A1
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WO
WIPO (PCT)
Prior art keywords
cyclohexyl
dihydro
monosaccharide
product
toluene
Prior art date
Application number
PCT/EP1998/004931
Other languages
French (fr)
Inventor
Nigel Derek Arthur Walshe
Selena Jane Cambers
Original Assignee
Pfizer Limited
Pfizer Inc.
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Filing date
Publication date
Priority to HU0003399A priority Critical patent/HU228202B1/en
Priority to US10/203,869 priority patent/US6906184B1/en
Application filed by Pfizer Limited, Pfizer Inc. filed Critical Pfizer Limited
Priority to IL15646498A priority patent/IL156464A/en
Priority to PL338557A priority patent/PL191259B1/en
Priority to UA99127066A priority patent/UA56244C2/en
Priority to DK98946289T priority patent/DK1003764T3/en
Priority to JP51168199A priority patent/JP3476476B2/en
Priority to BRPI9811826A priority patent/BRPI9811826B8/en
Priority to KR1020007001184A priority patent/KR100336060B1/en
Priority to AU93396/98A priority patent/AU731854B2/en
Priority to CA002296109A priority patent/CA2296109C/en
Priority to SK137-2000A priority patent/SK283899B6/en
Priority to IL15646398A priority patent/IL156463A0/en
Priority to AT98946289T priority patent/ATE238333T1/en
Priority to EP98946289A priority patent/EP1003764B1/en
Priority to NZ501969A priority patent/NZ501969A/en
Priority to IL13362898A priority patent/IL133628A0/en
Priority to DE69813830T priority patent/DE69813830T2/en
Priority to EA199901056A priority patent/EA002103B1/en
Publication of WO1999007721A1 publication Critical patent/WO1999007721A1/en
Priority to NO996521A priority patent/NO996521L/en
Priority to HR970350A priority patent/HRP20000054B1/en
Priority to HK01101581A priority patent/HK1030610A1/en
Priority to IL156463A priority patent/IL156463A/en

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
    • C07H1/00—Processes for the preparation of sugar derivatives
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
    • C07H19/00—Compounds containing a hetero ring sharing one ring hetero atom with a saccharide radical; Nucleosides; Mononucleotides; Anhydro-derivatives thereof
    • C07H19/01—Compounds containing a hetero ring sharing one ring hetero atom with a saccharide radical; Nucleosides; Mononucleotides; Anhydro-derivatives thereof sharing oxygen
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P33/00—Antiparasitic agents
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P33/00—Antiparasitic agents
    • A61P33/10—Anthelmintics
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P33/00—Antiparasitic agents
    • A61P33/14—Ectoparasiticides, e.g. scabicides
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
    • C07H17/00—Compounds containing heterocyclic radicals directly attached to hetero atoms of saccharide radicals
    • C07H17/04—Heterocyclic radicals containing only oxygen as ring hetero atoms
    • C07H17/08—Hetero rings containing eight or more ring members, e.g. erythromycins

Definitions

  • This invention relates to an improved process for the preparation of an antiparasitic agent derived from doramectin, and intermediates therefor.
  • Doramectin is a widely employed fermentation derived antiparasitic agent, active against a wide variety of nematode and arthropod parasites in sheep and cattle.
  • avermectin 5-oxime monosaccharide derivatives including the compound 25-cyclohexyl-22,23-dihydro-5- hydroxyiminoavermectin B1 monosaccharide (named in that application as 5- oximino-22,23-dihydro-25-cyclohexylavermectin B1 monosaccharide) derived from doramectin.
  • This compound has been found to have exceptional activity against fleas and heartworm combined with low toxicity which makes it particularly valuable for use in domestic animals such as cats and dogs.
  • this compound is prepared from doramectin by a process which involves firstly hydrogenation to give 25- cyclohexyl-22,23-dihydroavermectin B1 , followed by mild acid treatment to hydrolyse one of the C-13 ⁇ -oleandrosyl groups to give the corresponding monosaccharide derivative. This product is then oxidised to give the 5-oxo derivative which is finally reacted with hydroxylamine hydrochloride to yield the 5- oxime.
  • reaction of this intermediate with hydroxylamine hydrochloride to give the 5-oxime and the hydrolysis step to give the monosaccharide derivative may be performed as a single concurrent reaction and this further improvement reduces the number of individual steps in the process which reduces handling and isolation steps leading to an improvement in the overall yield and quality of the final product.
  • the final product can itself be recrystallised from a range of organic solvents, including in particular toluene or methanol and this forms a further aspect of the present invention.
  • the nomenclature used in the present application is adapted from that used for the avermectins.
  • the symbols A and B are used to designate a methoxy or hydroxy group at the 5-position respectively;
  • the numeral 1 is used to designate a double bond at the C-22,23 position and 2 to designate the absence of the double bond and presence of a C-23 hydroxy group;
  • the symbols a and b indicate a sec-butyl or iso-propyl group at the C-25 position respectively.
  • doramectin is 25(R)-25-cyclohexyl-5-O-demethyl-25-de(1- methylpropyl)avermectin A1a, although it is more generally described in the previous publications as 25-cyclohexyl avermectin B1.
  • the overall process for preparing 25- cyclohexyl-22,23-dihydro-5-hydroyximinoavermectin B1 monosaccharide comprises the steps of: (i) catalytic hydrogenation of doramectin in an organic solvent to yield 25- cyclohexyl-22,23-dihydroavermectin B1.
  • novel intermediate 25-cyclohexyl-22,23-dihydro-5-oxoavermectin B1 is also active in its own right as an antiparasitic agent as well as being a key intermediate in the present process.
  • the first step in the above process is generally performed using acetone as solvent and using Wilkinson's catalyst (tris(triphenylphosphine)rhodium (1) chloride). Hydrogenation is effected at a pressure of 3 to 4 bar and is generally complete after a period of 6-10 hours at 20-30°C.
  • the product (II) is isolated by filtration and removal of the solvent.
  • the oxidation step is again generally performed in acetone in the presence of manganese dioxide at room temperature but other organic solvents may also be used. Reaction is generally complete after 1 to 3 hours and the reaction mixture is filtered, the solvent replaced by isopropanoi or methanol under reflux and water added. On cooling 25-cyclohexyl-22,23-dihydro-5-oxoavermectin B1 (III) crystallises from solution and is collected and dried.
  • the final step of the process is performed by treating the above 5-oxo intermediate with hydroxylamine hydrochloride.
  • the reaction is generally performed in aqueous isopropanoi at a temperature of from 30°C to reflux temperature, preferably at 40-50°C. Formation of the 5-oxime and hydrolysis of the terminal C-13 saccharide group proceed concurrently and the reaction is monitored, for example by high pressure liquid chromatography, until complete. Water immiscible organic solvents, e.g. toluene and t-butyl methyl ether are added, the organic layer washed, typically with dilute sodium bicarbonate and brine, dried if needed and the solvent removed.
  • solvents e.g. toluene and t-butyl methyl ether
  • the crude product can be further purified by crystallisation from toluene and is obtained as a variable solvate which collapses to an amorphous powder on drying under vacuum.
  • the product (IV) is crystallised or recrystallised from methanol and is obtained as a white crystalline solid, again as a variable methanol/water solvate.
  • reaction volume was then adjusted to 700 ml, by further distillation, or by adding additional isopropyl alcohol, and reflux stopped. Water (7 ml) was added and the reaction allowed to cool to room temperature, whereupon the product crystallised from solution. This was granulated overnight at room temperature, the product collected by filtration, washed with isopropyl alcohol and oven dried at 50°C under vacuum to yield the title product as a pale yellow solid(152.5 g, 81.3%).
  • H.P.L.C Novapak (trade mark) C18, 150mm - 3.9mm column, mobile phase acitonitrile, water (80:20 v/v), flow rate 1.0 ml/minute, retention time 19 minutes.
  • the layers were then allowed to separate and the resulting organic layer was washed with 5% w/v aqueous sodium bicarbonate solution (60 ml) and then 20% w/v brine solution (60 ml).
  • the final organic layer was distilled to low volume and toluene added. The distillation was continued (adding more toluene as and when necessary) until the reflux temperature was 111°C (boiling point of toluene).
  • the reaction volume was then adjusted to 120 ml by further distillation, or by adding additional toluene and the reaction was then allowed to cool to room temperature and the desired product crystallised from solution.
  • Toluene-crystallised solid (121g) was dissolved in methanol (525 ml) and heated to reflux. Solvent was removed by distillation until the product started to crystallise from solution. The reaction mixture was allowed to cool to below the reflux temperature and water (31 ml) added. The solution was then allowed to cool to room temperature to allow crystallisation and allowed to granulate overnight.
  • the product was collected by filtration, washed with methanol and oven dried at 50°C under vacuum to yield the title product as a white, crystalline solid.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biochemistry (AREA)
  • Molecular Biology (AREA)
  • Genetics & Genomics (AREA)
  • Biotechnology (AREA)
  • Engineering & Computer Science (AREA)
  • Veterinary Medicine (AREA)
  • Animal Behavior & Ethology (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Public Health (AREA)
  • Pharmacology & Pharmacy (AREA)
  • Tropical Medicine & Parasitology (AREA)
  • General Chemical & Material Sciences (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Medicinal Chemistry (AREA)
  • Saccharide Compounds (AREA)
  • Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
  • Heterocyclic Carbon Compounds Containing A Hetero Ring Having Oxygen Or Sulfur (AREA)
  • Acyclic And Carbocyclic Compounds In Medicinal Compositions (AREA)

Abstract

An improved process for the preparation of the antiparasitic compound 25-cyclohexyl-22,23-dihydro-5-hydroxyiminoavermectin B1 monosaccharide from doramectine and intermediates therefor and crystalline solvates thereof.

Description

IMPROVED PROCESS FOR ANTIPARASITIC AGENT
This invention relates to an improved process for the preparation of an antiparasitic agent derived from doramectin, and intermediates therefor. Doramectin is a widely employed fermentation derived antiparasitic agent, active against a wide variety of nematode and arthropod parasites in sheep and cattle. According to the specification of our International patent application WO 94/15944 we describe and claim a variety of avermectin 5-oxime monosaccharide derivatives including the compound 25-cyclohexyl-22,23-dihydro-5- hydroxyiminoavermectin B1 monosaccharide (named in that application as 5- oximino-22,23-dihydro-25-cyclohexylavermectin B1 monosaccharide) derived from doramectin. This compound has been found to have exceptional activity against fleas and heartworm combined with low toxicity which makes it particularly valuable for use in domestic animals such as cats and dogs. As described in our earlier application, this compound is prepared from doramectin by a process which involves firstly hydrogenation to give 25- cyclohexyl-22,23-dihydroavermectin B1 , followed by mild acid treatment to hydrolyse one of the C-13 α-oleandrosyl groups to give the corresponding monosaccharide derivative. This product is then oxidised to give the 5-oxo derivative which is finally reacted with hydroxylamine hydrochloride to yield the 5- oxime.
However, like most of the avermectins, all of the intermediates involved in this process are obtained as gums or amorphous solids which require purification by chromatography and the process is thus not readily amenable to scale-up. We have now surprisingly discovered that by performing the reaction sequence in a different order, with the hydrogenation and oxidation steps performed first, the resulting novel intermediate, (25S)-25-cyclohexyl-5-demethoxy-25-de(1- methylpropyl)-22,23-dihydro-5-oxoavermectin A1 a (25-cyclohexyl-22,23-dihydro-5- oxoavermectin B1) can be crystallised from an aqueous lower alkanol such as methanol or isopropanoi and this greatly facilitates the isolation and purification of this intermediate. We have further discovered that reaction of this intermediate with hydroxylamine hydrochloride to give the 5-oxime and the hydrolysis step to give the monosaccharide derivative may be performed as a single concurrent reaction and this further improvement reduces the number of individual steps in the process which reduces handling and isolation steps leading to an improvement in the overall yield and quality of the final product. Moreover we have now unexpectedly discovered that the final product can itself be recrystallised from a range of organic solvents, including in particular toluene or methanol and this forms a further aspect of the present invention.
The nomenclature used in the present application is adapted from that used for the avermectins. Thus the symbols A and B are used to designate a methoxy or hydroxy group at the 5-position respectively; the numeral 1 is used to designate a double bond at the C-22,23 position and 2 to designate the absence of the double bond and presence of a C-23 hydroxy group; and the symbols a and b indicate a sec-butyl or iso-propyl group at the C-25 position respectively. Thus the chemical name for doramectin is 25(R)-25-cyclohexyl-5-O-demethyl-25-de(1- methylpropyl)avermectin A1a, although it is more generally described in the previous publications as 25-cyclohexyl avermectin B1. Similarly the compound - 25-cyclohexyl-22,23-dihydro-5-hydroxyiminoavermectin B1 monosaccharide is more correctly referred to as (5Z, 25S)-25-cyclohexyl-4'-O-de(2,6-dideoxy-3-O- methyl-α-L-arao//7θ-hexopyranosyl)-5-demethoxy-25-de(1-methylpropyl)-22,23- dihydro-5-hydroxyiminoavermectin A1a. For the sake of clarity and brevity the short form of nomenclature will continue to be used in the present specification although both names are included in the experimental section.
According to the present invention the overall process for preparing 25- cyclohexyl-22,23-dihydro-5-hydroyximinoavermectin B1 monosaccharide comprises the steps of: (i) catalytic hydrogenation of doramectin in an organic solvent to yield 25- cyclohexyl-22,23-dihydroavermectin B1.
(ii) oxidising the above product with manganese dioxide in an organic solvent to yield 25-cyclohexyl-22,23-dihydro-5-oxoavermectin B1 and if desired crystallising the product.
(iii) reacting the above product with hydroxylamine hydrochloride in an aqueous organic solvent.
(iv) optionally crystallising the product from toluene and/or methanol. The novel intermediate 25-cyclohexyl-22,23-dihydro-5-oxoavermectin B1 is also active in its own right as an antiparasitic agent as well as being a key intermediate in the present process.
The process is shown in the following reaction scheme:
Doramectin
Figure imgf000006_0001
The first step in the above process is generally performed using acetone as solvent and using Wilkinson's catalyst (tris(triphenylphosphine)rhodium (1) chloride). Hydrogenation is effected at a pressure of 3 to 4 bar and is generally complete after a period of 6-10 hours at 20-30°C. The product (II) is isolated by filtration and removal of the solvent.
The oxidation step is again generally performed in acetone in the presence of manganese dioxide at room temperature but other organic solvents may also be used. Reaction is generally complete after 1 to 3 hours and the reaction mixture is filtered, the solvent replaced by isopropanoi or methanol under reflux and water added. On cooling 25-cyclohexyl-22,23-dihydro-5-oxoavermectin B1 (III) crystallises from solution and is collected and dried.
The final step of the process is performed by treating the above 5-oxo intermediate with hydroxylamine hydrochloride. The reaction is generally performed in aqueous isopropanoi at a temperature of from 30°C to reflux temperature, preferably at 40-50°C. Formation of the 5-oxime and hydrolysis of the terminal C-13 saccharide group proceed concurrently and the reaction is monitored, for example by high pressure liquid chromatography, until complete. Water immiscible organic solvents, e.g. toluene and t-butyl methyl ether are added, the organic layer washed, typically with dilute sodium bicarbonate and brine, dried if needed and the solvent removed. The crude product can be further purified by crystallisation from toluene and is obtained as a variable solvate which collapses to an amorphous powder on drying under vacuum. Alternatively the product (IV) is crystallised or recrystallised from methanol and is obtained as a white crystalline solid, again as a variable methanol/water solvate.
The following Examples illustrate the process of the present invention, the preparation of the intermediate 25-cyclohexyl-22,23-dihydro-5-oxoavermectin B1 and its use in the preparation of 25-cyclohexyl-22,23-dihydro-5-hydroxyimino- avermectin B1 monosaccharide. Yields are quoted based on the activity of the doramectin starting material, and of the product. EXAMPLE 1 (25S 25-Cvclohexyl-5-O-demethyl-25-de(1-methylpropyn-22.23- dihydroavermectin A1a :[ 25-cyclohexyl-22.23-dihydroavermectin B1]
(25R)-25-Cyclohexyl-5-O-demethyl-25-de(1 -methylpropyl)avermectin A1 a (doramectin) (500g) was dissolved in acetone (2500 ml). The solution was charged to a 5 litre stainless steel Buchi hydrogenator and purged with nitrogen. Wilkinson's catalyst (tris(triphenylphosphine) rhodium (I) chloride ) (9.5g) was added and the reaction hydrogenated at 3.45 bar (50 psi) hydrogen pressure at room temperature. After 8 hours, the reaction was complete and the reaction mixture was filtered to remove insolubles. The resulting liquor was concentrated to dryness under vacuum and the resulting brown foam washed with acetonitrile and oven-dried at 50°C under vacuum to yield the title product as a cream solid (416 g, 90%).
EXAMPLE 2
(25S)-25-cvclohexyl-5-demethoxy-25-de(1-methylpropyπ-22.23-dihydro-5-oxo- avermectin A1a :[ 25-cyclohexyl-22.23-dihydro-5-oxoavermectin B1]
(25S)-25-cyclohexyl-5-0-demethyl-25-de(1-methylpropyl)-22,23- dihydroavermectin A1a (200g) was dissolved in acetone (1600 ml). Activated manganese dioxide (483g) was added and the resulting slurry stirred at room temperature. After 1-2 hours, the reaction was complete and the mixture was filtered through a clarcel pad to remove the manganese dioxide. The resulting filtration liquor was distilled to low volume, then isopropyl alcohol was added and distillation continued (adding more isopropyl alcohol as and when necessary) until the reflux temperature was 82°C (equivalent to the boiling point of isopropyl alcohol). The reaction volume was then adjusted to 700 ml, by further distillation, or by adding additional isopropyl alcohol, and reflux stopped. Water (7 ml) was added and the reaction allowed to cool to room temperature, whereupon the product crystallised from solution. This was granulated overnight at room temperature, the product collected by filtration, washed with isopropyl alcohol and oven dried at 50°C under vacuum to yield the title product as a pale yellow solid(152.5 g, 81.3%).
H.P.L.C: Novapak (trade mark) C18, 150mm - 3.9mm column, mobile phase acitonitrile, water (80:20 v/v), flow rate 1.0 ml/minute, retention time 19 minutes.
M.S: (positive ion electrospray) MNa+ = 923.3.
N.M.R: spectrum fully consistent with the assigned structure.
EXAMPLE 3
(5Z.25S 25-cvclohexyl-4'-Q-de(2.6-dideoxy-3-0-methyl-α-L-araD/t7o- hexopyranosyl)-5-demethoxy-25-de(1-methylpropyl)-22,23-dihydro-5- hvdroxyimino-avermectin A1 a:[ 25-cyclohexyl-22.23-dihydro-5-hydroxyimino- avermectin B1 monosaccharide]
(25S)-25-cyclohexyl-5-demethoxy-25-de(1-methylpropyl)-22,23-dihydro-5-oxo- avermectin A1a (15g) was stirred with isopropyl alcohol (120 ml) and water (15 ml) to give a pale yellow slurry. Hydroxylamine hydrochloride (4.67g) was added and the reaction heated to 40-45°C, whereupon a solution formed. After 14 hours, the reaction was complete and was allowed to cool to room temperature, tert-butyl methyl ether (60 ml), toluene (60 ml) and water (30 ml) were added and the reaction stirred well. The layers were then allowed to separate and the resulting organic layer was washed with 5% w/v aqueous sodium bicarbonate solution (60 ml) and then 20% w/v brine solution (60 ml). The final organic layer was distilled to low volume and toluene added. The distillation was continued (adding more toluene as and when necessary) until the reflux temperature was 111°C (boiling point of toluene). The reaction volume was then adjusted to 120 ml by further distillation, or by adding additional toluene and the reaction was then allowed to cool to room temperature and the desired product crystallised from solution. This was granulated overnight at room temperature, the product collected by filtration and washed with toluene, to yield the final product, a crystalline solid, as a toluene solvate of variable stoicheometry. The product was dried under vacuum at 50°C to yield the title product as a white amorphous powder (9.9 g, 77%).
Alternative Recrvstallisation of (5Z.25S)-25-cyclohexyl-4'-0-de(2.6-dideoxy-3-0- methyl-α-L-araD/t7θ-hexopyranosyl)-5-demethoxy-25-de(1-methylpropyπ-22.23- dihydro-5-hydroxyiminoavermectin A1 a
The process is the same as above as far as the isolation of the toluene crystallised material. In the alternative process this solid is not oven dried, but is dissolved in methanol.
Toluene-crystallised solid (121g) was dissolved in methanol (525 ml) and heated to reflux. Solvent was removed by distillation until the product started to crystallise from solution. The reaction mixture was allowed to cool to below the reflux temperature and water (31 ml) added. The solution was then allowed to cool to room temperature to allow crystallisation and allowed to granulate overnight.
The product was collected by filtration, washed with methanol and oven dried at 50°C under vacuum to yield the title product as a white, crystalline solid.
(88.15g, 68.6%). The product was obtained as a methanol/water solvate of variable stoicheometry.

Claims

1. A process for the preparation of 25-cyclohexyl-22,23-dihydro-5-hydroximino- avermectin B1 monosaccharide which comprises reacting 25-cyclohexyl-22,23- dihydro-5-oxoavermectin B1 with hydroxylamine hydrochloride in an aqueous organic solvent.
2. A process as claimed in claim 1 wherein the solvent is aqueous isopropyl alcohol.
3. A process as claimed in claim 2 wherein the process is performed at a temperature of from 40-50┬░C.
4. A process as claimed in any one of claims 1 to 3 wherein the product is crystallised from toluene and/or methanol.
5. 25-Cyclohexyl-22,23-dihydro-5-oxoavermectin B1.
6. A process for preparing 25-cyclohexyl-22,23-dihydro-5-oxoavermectin B1 which comprises oxidising 25-cyclohexyl-22,23-dihydroavermectin B1.
7. A process as claimed in claim 6 wherein said process is performed with manganese dioxide in an organic solvent.
8. A process as claimed in claim 7 wherein the solvent is acetone.
9. A process for preparing 25-cyclohexyl-22,23-dihydro-5- hydroxyiminoavermectin B1 monosaccharide from doramectin which comprises the steps of-:
(i) catalytic hydrogenation in an organic solvent,
(ii) oxidation with manganese dioxide in an organic solvent and, if desired crystallising the product, (iii) reaction with hydroxylamine hydrochloride in an aqueous organic solvent.
(iv) optionally recrystallising the product from toluene or methanol.
10. . Crystalline 25-cyclohexyl-22,23-dihydro-5-hydroxyiminoavermectin B1 monosaccharide toluene solvate obtained by recrystallising 25-cyclohexyl-22,23- dihydro-5-hydroxyiminoavermectin B1 monosaccharide from toluene.
11. Crystalline 25-cyclohexyl-22,23-dihydro-5-hydroxyiminoavermectin B1 monosaccharide methanol/water solvate obtained by crystallising 25-cyclohexyl- 22,23-dihydro-5-hydroxyiminoavermectin B1 monosaccharide from aqueous methanol.
PCT/EP1998/004931 1997-08-05 1998-07-23 Improved process for antiparasitic agent WO1999007721A1 (en)

Priority Applications (23)

Application Number Priority Date Filing Date Title
IL15646398A IL156463A0 (en) 1997-08-05 1998-07-23 Improved process for antiparasitic agent
SK137-2000A SK283899B6 (en) 1997-08-05 1998-07-23 Improved process for antiparasitic agent
IL15646498A IL156464A (en) 1997-08-05 1998-07-23 Crystalline solvate of 25-cyclohexyl-22, 23-dihydro-5-hydroxyiminoavermectin b1 monosaccharide
US10/203,869 US6906184B1 (en) 1997-08-05 1998-07-23 Process for antiparasitic agent
UA99127066A UA56244C2 (en) 1997-08-05 1998-07-23 An improved process for the preparation of the antiparasitic compound
DK98946289T DK1003764T3 (en) 1997-08-05 1998-07-23 Improved method of preparing an antiparasitic agent
AT98946289T ATE238333T1 (en) 1997-08-05 1998-07-23 IMPROVED METHOD FOR PRODUCING ANTIPARASIC AGENTS
BRPI9811826A BRPI9811826B8 (en) 1997-08-05 1998-07-23 processes for the preparation of monosaccharides
KR1020007001184A KR100336060B1 (en) 1997-08-05 1998-07-23 Improved Process for Antiparasitic Agent
AU93396/98A AU731854B2 (en) 1997-08-05 1998-07-23 Improved process for antiparasitic agent
CA002296109A CA2296109C (en) 1997-08-05 1998-07-23 Improved process for antiparasitic agent
HU0003399A HU228202B1 (en) 1997-08-05 1998-07-23 Process for preparing antiparasitic agent
PL338557A PL191259B1 (en) 1997-08-05 1998-07-23 Method for manufacture of (5Z,25S)-25-cyclohexyl- 4'-O-de-(2,6-dideoxy-3-O-methyl-alpha-L -arabinohexopyranosyl)-5-demethoxy-25-de-(1-methylpropyl)-22,23-dihydro-5-hydro-Al xyiminoavermectine, (25S)-25-cyclohexyl-4'-O-de-(2,6-dideoxy-3-)-methyl-alpha-L-ar
JP51168199A JP3476476B2 (en) 1997-08-05 1998-07-23 How to improve antiparasitic agents
EP98946289A EP1003764B1 (en) 1997-08-05 1998-07-23 Improved process for preparing antiparasitic agent
NZ501969A NZ501969A (en) 1997-08-05 1998-07-23 Process for making 25-cyclohexyl-22,23-dihydro-5-oxoavermectin B1 being a derivative of doramectin with antiparasitic activity being performed 40-50 deg celsius
IL13362898A IL133628A0 (en) 1997-08-05 1998-07-23 Improved process for antiparasitic agent
DE69813830T DE69813830T2 (en) 1997-08-05 1998-07-23 IMPROVED METHOD FOR PRODUCING ANTIPARASITIC AGENTS
EA199901056A EA002103B1 (en) 1997-08-05 1998-07-23 Improved process for antiparasitic agent
NO996521A NO996521L (en) 1997-08-05 1999-12-28 Process for the preparation of antiparasitic agent
HR970350A HRP20000054B1 (en) 1997-08-05 2000-01-31 Improved process for antiparasitic agent
HK01101581A HK1030610A1 (en) 1997-08-05 2001-03-05 Improved process for antiparaistic agent.
IL156463A IL156463A (en) 1997-08-05 2003-06-16 Process for the preparation of 25-cyclohexyl-22,23-dihydro-5-oxoavermectin b1

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WO2013149577A1 (en) 2012-04-03 2013-10-10 浙江海正药业股份有限公司 New synthesis process of antiparasitic drug selamectin
EP3150618A1 (en) 2015-09-29 2017-04-05 Virbac Process for the preparation of selamectin
WO2018167271A1 (en) 2017-03-17 2018-09-20 Krka, D.D., Novo Mesto Stable topical veterinary composition
WO2023203038A1 (en) 2022-04-19 2023-10-26 Syngenta Crop Protection Ag Insect, acarina and nematode pest control

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CA2513662C (en) 2003-01-20 2012-08-07 Lg Electronics Inc. Recording medium having data structure for managing reproduction of still pictures recorded thereon and recording and reproducing methods and apparatuses
CN105061457B (en) * 2015-08-20 2016-06-22 湖北宏中药业股份有限公司 A kind of synthetic method of milbemycin oxime
CN107021990B (en) * 2017-06-14 2019-07-12 博瑞生物医药（苏州）股份有限公司 The preparation method of high-purity selamectin
CN107118247B (en) * 2017-06-14 2019-07-26 博瑞生物医药（苏州）股份有限公司 The preparation method of selamectin
CN109734760A (en) * 2018-11-01 2019-05-10 丽珠集团新北江制药股份有限公司 A kind of preparation method of doractin impurity
CN112830945A (en) * 2019-11-22 2021-05-25 东莞市东阳光动物保健药品有限公司 Preparation method of macrolide compound
CN111116692A (en) * 2020-01-14 2020-05-08 北大方正集团有限公司 Synthesis method of high-purity selamectin
CN114106071A (en) * 2021-11-11 2022-03-01 浙江荣耀生物科技股份有限公司 Synthesis method of selamectin

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Cited By (9)

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Publication number Priority date Publication date Assignee Title
WO2013149577A1 (en) 2012-04-03 2013-10-10 浙江海正药业股份有限公司 New synthesis process of antiparasitic drug selamectin
CN103360444A (en) * 2012-04-03 2013-10-23 浙江海正药业股份有限公司 Novel synthesis process of antiparasitic drug, namely selamectin
EP2835376A4 (en) * 2012-04-03 2015-11-25 Zhejiang Hisun Pharm Co Ltd New synthesis process of antiparasitic drug selamectin
CN103360444B (en) * 2012-04-03 2016-05-11 浙江海正药业股份有限公司 The new technique for synthesizing of antiparasitic agent selamectin
US10053483B2 (en) 2012-04-03 2018-08-21 Zhejiang Hisun Pharmaceutical Co., Ltd. Synthesis process of antiparasitic drug selamectin
EP3150618A1 (en) 2015-09-29 2017-04-05 Virbac Process for the preparation of selamectin
WO2017055502A1 (en) 2015-09-29 2017-04-06 Virbac New synthesis process for the preparation of selamectin, and intermediates thereof
WO2018167271A1 (en) 2017-03-17 2018-09-20 Krka, D.D., Novo Mesto Stable topical veterinary composition
WO2023203038A1 (en) 2022-04-19 2023-10-26 Syngenta Crop Protection Ag Insect, acarina and nematode pest control

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