Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D239/00—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings
  • C07D239/02—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings not condensed with other rings
  • C07D239/24—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings not condensed with other rings having three or more double bonds between ring members or between ring members and non-ring members
  • C07D239/28—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings not condensed with other rings having three or more double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, directly attached to ring carbon atoms
  • C07D239/46—Two or more oxygen, sulphur or nitrogen atoms
  • C07D239/52—Two oxygen atoms
  • C07D239/54—Two oxygen atoms as doubly bound oxygen atoms or as unsubstituted hydroxy radicals

Definitions

• the present invention concerns a process for making 4,6-dihydroxypyrimidine.
• 4,6- Dihydroxypyrimidine is a useful chemical intermediate (especially in the agrochemical industry).
• the present invention provides a process for preparing 4,6-dihydroxypyrimidine comprising the steps: a) contacting formamide, an alkoxide of formula ROM and a malonate of formula CH 2 (CO2R)2 in a solvent of formula ROH; b) adding water to the product of step (a); c) removing substantially all of the solvent of formula ROH from the product of step (b); and d) acidifying the product of step (c) wherein R is C M alkyl and M is an alkali metal.
• the addition of water before the removal of the solvent of formula ROH enables more organic material to be recovered during step (c) because the following reaction takes place:
• Alkyl groups contain from 1 to 4 carbon atoms and are straight or branched chain.
• Alkyl is, for example, methyl or ethyl, but is preferably methyl.
• Alkali metals are, for example, sodium or potassium.
• Step (a) of the process of the invention can be conducted in a number of ways but it is preferred that: i) formamide is contacted with an alkoxide of formula ROM in a solvent of formula ROH; and ii) the product of (i) is contacted with a malonate of formula CH2(CO 2 R)2 It is preferred that malonate of formula CH 2 (CO 2 R) 2 is added to the product of (i) at an elevated temperature (such as a temperature in the range 40-80°C, especially 40-60°C).
• an elevated temperature such as a temperature in the range 40-80°C, especially 40-60°C.
• the molar ratio of formamide:ROM:CH2(CO2R)2 in step (a) is in the range (2.0-4.0):(3.0-4.0):(0.8-1.2), especially in the range (3.0-3.2):(3.3-3.7):(0.9-l. l), more preferably about 3 : 3.5 : 1.
• a preferred method for solvent removal is distillation, especially distillation under reduced pressure. Substantially all of the solvent of formula ROH is removed when more than 95% (preferably more than 98%) is removed. When the solvent of formula ROH is removed water may also be removed to leave a solid residue, an aqueous slurry or a solution in water. (It is preferred that not all the water is removed, that is, that after removal of the solvent of formula ROH an aqueous slurry or a solution in water remains.) Water is added to the solid residue or aqueous slurry so that complete dissolution is achieved before step (d) is carried out.
• Acidification (step (d)) of the product of step (c) of the present invention is preferably acidification to a pH in the range 1 -5 (for example 1.5-4.0), especially in the range 2-3, particularly about 2.1. While acidification can be carried out using a suitable ion exchange resin it is preferred that a strong mineral acid (such as nitric acid, hydrochloric acid or sulphuric acid), or a suitable organic acid (such as acetic acid) is used.
• a strong mineral acid such as nitric acid, hydrochloric acid or sulphuric acid
• a suitable organic acid such as acetic acid
• step (c) When the product of step (c) is acidified 4,6-dihydroxypyrimidine precipitates.
• it is preferred especially when sulphuric acid is used for the acidification
• to keep the temperature above 25°C especially in the range 30-40°C. In this way, it is possible to obtain product that can be used as a chemical intermediate without the need for further purification.
• the acidification in step (d) can be achieved by the addition of a suitable acid to the product of step (c) or, preferably, by the addition of the product of step (c) to a suitable acid.
• the present invention provides a process for preparing 4,6- dihydroxypyrimidine, the process comprising adding a malonate of formula CH2(CO 2 R)2 to a mixture of formamide and an alkoxide of formula ROM in a solvent of formula ROH at an elevated temperature and heating the resulting mixture at an elevated temperature (especially in the range 40-80°C). After a suitable length of time water is added to the resulting mixture and substantially all the solvent of formula ROH removed to leave an aqueous slurry. If necessary water is added to the aqueous residue to ensure that all solids are in solution and the solution is acidified and 4,6-dihydroxypyrimidine precipitates out.
• the product can be collected by filtration.
• nuclear magnetic "resonance (NMR) data are expressed in parts per million (ppm) from tetramethylsilane.
• a D2O solution of the disodium salt of 4,6-dihydroxypyrimidine was prepared by treating a sample of 4,6-dihydroxypyrimidine with a solution of a suitable amount of sodium hydroxide in D 2 O. Proton NMR of the resulting solution showed peaks at 7.4(H-2) and 4.7(H-5) ppm.
• a D2O solution of the dipotassium salt of 4,6-dihydroxypyrimidine was prepared by treating a sample of 4,6-dihydroxypyrimidine with a solution of a suitable amount of potassium hydroxide in D2O.
• I3 C NMR of the resulting solution showed peaks at 179.2(C-4 & C-6), 160.9(C-2) and 93.8(C-5) ppm.
• Proton NMR of a solution of 4,6-dihydroxypyrimidine in dimethylsulphoxide (DMSO) showed peaks at 8.0(H-2) and 5.2(H-5) ppm.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
• Agricultural Chemicals And Associated Chemicals (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
• Plural Heterocyclic Compounds (AREA)

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• 1996
  • 1996-05-17 GB GBGB9610320.5A patent/GB9610320D0/en active Pending
• 1997
  • 1997-04-24 AU AU23979/97A patent/AU2397997A/en not_active Abandoned
  • 1997-04-24 CN CN97193112A patent/CN1105110C/zh not_active Expired - Fee Related
  • 1997-04-24 JP JP09541756A patent/JP2000510864A/ja not_active Ceased
  • 1997-04-24 WO PCT/GB1997/001136 patent/WO1997044327A1/en not_active Ceased
  • 1997-04-24 IL IL12698997A patent/IL126989A/xx not_active IP Right Cessation
  • 1997-04-24 EP EP97919544A patent/EP0901475A1/en not_active Withdrawn
  • 1997-04-24 BR BR9709096A patent/BR9709096A/pt not_active Application Discontinuation
  • 1997-05-01 TW TW086105803A patent/TW404943B/zh not_active IP Right Cessation
  • 1997-05-02 IN IN1145DE1997 patent/IN186126B/en unknown
  • 1997-05-05 ZA ZA9703847A patent/ZA973847B/xx unknown
  • 1997-05-12 AR ARP970101970A patent/AR007091A1/es active IP Right Grant
• 1998
  • 1998-11-13 US US09/191,491 patent/US6096892A/en not_active Expired - Fee Related

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