Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C277/00—Preparation of guanidine or its derivatives, i.e. compounds containing the group, the singly-bound nitrogen atoms not being part of nitro or nitroso groups
  • C07C277/08—Preparation of guanidine or its derivatives, i.e. compounds containing the group, the singly-bound nitrogen atoms not being part of nitro or nitroso groups of substituted guanidines

Definitions

• the present invention relates to a process for the preparation of 1-methyl-3-nitroguanidine, which is an important intermediate for the preparation of biologically active compounds, in particular insecticides (cf. "Nicotinoid Insecticides and the Nicotinic Acetylcholine Receptor", I.Yamamoto, JE Casida (Ed.) Springer-Verlag, Tokyo 1999).
• insecticides cf. "Nicotinoid Insecticides and the Nicotinic Acetylcholine Receptor", I.Yamamoto, JE Casida (Ed.) Springer-Verlag, Tokyo 1999.
• methylguanidine nitrate is obtained by reacting methylammonium nitrate with anhydrous cyanamide in organic solvents such as ethers or alcohols and then converted directly to 1-methyl-3-nitroguanidine.
• organic solvents such as ethers or alcohols
• 1-methyl-3-nitroguanidine can be obtained by nitrating methylguanidine sulfates (cf. J. Amer. Chem. Soc. 1933, 55, 731).
• This production method also has the disadvantage of an unsatisfactory yield and a relatively large amount of waste water.
• Methylisothiourea sulfate is nitrated and then the methyl mercapto group is substituted by a methylamino residue (cf. J. Amer. Chem. Soc. 1954, 76, 1877).
• the cleavage of methyl mercaptan especially when carried out on an industrial scale, poses considerable process engineering problems.
• the present invention was therefore based on the object of developing a process for the preparation of 1-methyl-3-nitroguanidine which does not have the disadvantages of the prior art, but rather the desired end product in very good yields and high purities in a particularly environmentally friendly and technically advantageous manner enables simple way.
• Methylammonium salt in aqueous solution at temperatures of 30 to 60 ° C and at a pH of 9.5 to 12.3. It has surprisingly been found here that, in addition to increasing the yield, the formation of N2O is also considerably reduced, which considerably reduces the risk of the formation of explosive mixtures with the ammonia formed as a by-product.
• nitroguanidine is therefore mixed with methylamine and / or
• Methylammonium salt in aqueous solution at temperatures from 30 to 60 ° C, especially at 40 to 45 ° C, implemented.
• the salts of strong mineral acids such as. B. the sulfate, hydrochloride, nitrate or phosphate can be used.
• the pH is adjusted either by adding the methylamine and the methylammonium salt in such molar ratios that the desired pH is set automatically, or by the usual use of strong bases or acids.
• a mineral acid selected from the group consisting of sulfuric acid, hydrochloric acid, nitric acid or phosphoric acid is preferably used as strong acids, while sodium hydroxide solution or potassium hydroxide solution, for example, is used as strong bases.
• the methylamine and / or the methylammonium salt are used in an amount such that the molar amount is the sum of the two components, based on the nitroguanidine used corresponds to an excess of 5 to 50 mol%.
• a higher excess of methylamine or methylammonium salt with up to 100% can be used without an essential formation of the dialkylated product 1, 2-dimethyl-3-nitroguanidine being observed.
• a higher excess than the preferred 5 to 50% by weight of methylamine or methylammonium salt reduces the economy of the process according to the invention.
• the end product After completion of the reaction, which is usually complete after 2 to 3 hours, the end product is preferably separated off by filtration. A neutralization of the reaction mixture before the filtration is also possible without this having any negative effect on the yield. Possibly . the end product can be washed with a little cold water and dried.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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• 2000
  • 2000-01-28 DE DE10003834A patent/DE10003834A1/de not_active Withdrawn
• 2001
  • 2001-01-12 DE DE50109873T patent/DE50109873D1/de not_active Expired - Lifetime
  • 2001-01-12 EP EP01901150A patent/EP1261581B1/de not_active Expired - Lifetime
  • 2001-01-12 ES ES01901150T patent/ES2261374T3/es not_active Expired - Lifetime
  • 2001-01-12 WO PCT/EP2001/000351 patent/WO2001055099A1/de not_active Ceased
  • 2001-01-12 JP JP2001555041A patent/JP4758584B2/ja not_active Expired - Fee Related
  • 2001-01-12 AT AT01901150T patent/ATE327218T1/de active
• 2002
  • 2002-06-05 US US10/161,619 patent/US6486348B1/en not_active Expired - Lifetime

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