Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D499/00—Heterocyclic compounds containing 4-thia-1-azabicyclo [3.2.0] heptane ring systems, i.e. compounds containing a ring system of the formula:, e.g. penicillins, penems; Such ring systems being further condensed, e.g. 2,3-condensed with an oxygen-, nitrogen- or sulfur-containing hetero ring

Definitions

• the invention relates to a novel process for the preparation of 6-aminopenicillanic acid 1,1-dioxide, hereinafter called 6-APA-sulfone, and its salts.
• European patent application publ. no. 0002927 describes the use of 6-APA-sulfone and its salts as agents for enhancing the antibacterial activity of ⁇ -lactam antibiotics, and its preparation by oxidation of 6-aminopenicillanic acid (6-AFA) with a known sulfone generating oxidation agent such as potassium permanganate or 3-chloro-perbenzoic acid.
• 6-amino group and the 3-carboxylic acid group have to be first protected with suitable groups which are removed after oxidation without affecting the ring structure of the molecule.
• trialkyloxonium fluoroborate or an iminohalogenating agent and an organic hydroxyl compound or its alkali metal compound followed, if necessary, by hydrolyzing.
• the examples only the methyl and trichloroethyl ester of benzylpenicillin acid 1- oxide in dichloromethane were treated with dimethylaniline and PC1 5 .
• alkyl groups such as a methyl group
• halogenating alkyl groups such as a 2, 2, 2-trichlo ethyl group
• aralkyl groups such as a benzyl group, a p-nitro- benzyl group, a p-methoxybenzyl group, a phenacyl and a benzhydryl group
• trialkylsilyl groups such as a trimethylsilyl group, and the like, but in the examples only the use of 2, 2, 2-trichloroethyl and p-nitrobenzyl groups is demonstrated.
• British patents 1,189,022 and 1,224,017 describe a method for preparing 6-aminopenicillanic acid by deacylating a 6-acylamino ⁇ enicillanic acid or a salt thereof by preparir.j a silyl ester of the ⁇ -acylaminopenicillanic acid or a salt thereof, treating it with an agent which forms an imino bond, introducing an -OR group to the carbon atom which is involved in the formation of the imino bond whereby R is an alkyl or arylkyl group, followed by splitting the imino bridge and the silyl ester group with agents containing a hydroxy group or with water.
• novel process of the invention for the preparation of 6-amino-penicillanic acid 1,1 -dioxide and its non-toxic, pharmaceutically acceptable salts comprises subjecting a member of the group consisting of a penicillin-1, 1 -dioxide and its salts of which the 3-carboxylic acid group is protected by such an easily removable group that a "one-pot process" is possible, to deacylation to form 6-APA-sulfone and its salts.
• the 3-carboxylic acid group of the penicillin-1,1-dioxide or its salt is protected by a silyl group, the protected penicillin-1,1-dioxide is treated with an agent which forms an imino bond, an -OR group is introduced to the carbon atom which is involved in the formation of the imino bond, R being an alkyl or aralkyl group with 1 to 6 alkyl carbon atoms, the imino bridge is split with an agent containing a hydroxy group or with water, and the protective group is simultaneously removed from the 3-carboxylic acid group.
• Suitable starting compounds for the method of the invention are penicillin-sulfones such as those described in U.S. patents No.
• the method of the invention has the great advantage with respect to the prior art in that raw materials are used as starting compounds and that these raw materials are easily obtained.
• raw materials are used as starting compounds and that these raw materials are easily obtained.
• benzylpenicillin and its salts are prepared in large amounts by fermentation.
• Another suitable penicillin which may be obtained by fermentation is phenoxymethylpenicillin and its salts, and in general phenylalkyl and phenoxyalkyl penicil- lins and their salts may be used. .
• the said compounds may be oxidized in a simple way to the corresponding penicillin-sulfones as indicated above and no special measures need to be taken to protect possibly sensitive groups in the molecule. Only in the deacylation step is the protection of the 3-carboxylic acid group necessary, but for that purpose the easily manageable silylation is used. Silyl groups are easily removed during the deacylation as they are be split simultaneously with the splitting of the imino bridge with a compound containing a hydroxy group or with water.
• easily removable protecting groups e.g. silicon, phosphorous or boron containing residues of which silicon containing residues are particularly preferred.
• Suitable silylating agents include, for example, trial- kylhalosilane such as trialkylchlorosilanes such as trimethyl- chlorosilane, dialkyldihalosilanes such as dialkyldichlorosilanes and nitrogen containing silanes such as N,0-bistrimethylsilylace- tamide, N,N , -bistrimethylsilylurea, hexamethyldisilazane or 3- trimethylsilyl-2-oxazolidinone.
• the reaction between the ⁇ enicillin-1,1-dioxide and the silylating agent, preferably dimethyldichlorosilane is preferably carried out in an inert organic solvent under substantially anhydrous conditions. The reaction may be carried out at various temperatures, for example between 0 and 40°C, and goes smoothly at room temperature.
• a reagent which forms an imino bond on the 6-amino nitrogen atom and examples of suitable reagents include iminohalogenating agents, such as PCI and P0C1 3 of which the former compound is preferred.
• the reaction is preferably carried out at lower temperatures. Suitable temperatures for the reaction are from about -60 to about 0°C, preferably from about -40 to about -10°C.
• an acid binding agent is added, for example, a tertiary amine such as pyridine, dimethylaniline or triethylamine. Preferably, dimethylaniline is used.
• suitable alcohols to be used in the formation of the imino ether include aliphatic alcohols of 1 to 6 carbon atoms and benzyl alcohol. Preferably, an alcohol with 3 or 4 carbon atoms is used of which isobutanol is particularly preferred.
• the intro- duction of the -OR group may be preferably carried, out at lower temperatures, for example from about -60 to about -10oC, preferably from about -50 to about -30°C.
• an acid binding agent is present also in this reaction such as a tertiary amine like pyridine, triethylamine or dimethylaniline.
• the product formed may be easily hydrolyzed, insofar as this did not occur already through the addition of the alcohol and for that purpose, water may be added to the reaction mixture.
• the 6-APA-sulfone or its salt may be easily obtained by working up the reaction mixture.
• the filtrate was extracted three times with 3.3 1 of ethyl acetate at a pH of 3 and the extract was dried over MgSO and concentrated to 400 ml during which a product crystallized.
• the crystalline mass was vacuum filtered and washed with an equal mixture of ethyl acetate and diethylether to obtain 170.8 g of benzylpenicillin-1,1- dioxide.
• Another 15 g of the product was obtained from the mother liqour for a total yield of 74%.
• EXAMPLE 5 The procedure of Example 1 was repeated, but instead of benzylpenicillin-1,1-dioxide,a corresponding amount of phenoxymethyl penicillin-1,1-dioxide, was used and the yield was 32%.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
• Preparation Of Compounds By Using Micro-Organisms (AREA)
• Cephalosporin Compounds (AREA)

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• 1979
  • 1979-12-10 NL NL7908867A patent/NL7908867A/nl not_active Application Discontinuation
• 1980
  • 1980-10-12 HU HU801412A patent/HU186392B/hu not_active IP Right Cessation
  • 1980-12-10 US US06/293,621 patent/US4422971A/en not_active Expired - Fee Related
  • 1980-12-10 EP EP80201192A patent/EP0030771B1/en not_active Expired
  • 1980-12-10 AU AU66431/81A patent/AU533912B2/en not_active Ceased
  • 1980-12-10 DE DE8080201192T patent/DE3062787D1/de not_active Expired
  • 1980-12-10 AT AT80201192T patent/ATE3042T1/de not_active IP Right Cessation
  • 1980-12-10 WO PCT/NL1980/000039 patent/WO1981001707A1/en not_active Ceased
  • 1980-12-10 JP JP50024781A patent/JPS56501680A/ja active Pending
• 1981
  • 1981-07-23 FI FI812312A patent/FI63411C/fi not_active IP Right Cessation
  • 1981-07-23 DK DK328581A patent/DK155604C/da not_active IP Right Cessation

Patent Citations (1)

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