Process for the N-alkylation or ureas

• US 5,124,451 A
• Filed: 07/10/1991
• Issued: 06/23/1992
• Est. Priority Date: 08/14/1990
• Status: Expired due to Fees

• Current Assignee: Chemie LINZ GmbH
• Original Assignee: Chemie LINZ GmbH
• Inventors: Falk, Heinz, Hackl, Kurt A.
• Primary Examiner(s): Ramsuer, Robert W.
• Application Number:
  US07/728,130
• Time in Patent Office: 349 Days
• Field of Search: 544/169, 546/226, 548/538, 564/56, 564/57, 564/61
• US Class Current: 544/169
• CPC Class Codes: C07C 273/1854 by reactions not involving the formation of the N-C(O)-N- moiety
• CPC Class Codes: C07C 275/06 of an acyclic and saturated carbon skeleton
• CPC Class Codes: C07D 295/215 Radicals derived from nitrogen analogues of carbonic acid

Abstract

Process for the N-alkylation of ureas by reacting a urea with an alkylating agent in the presence of a solid base and a phase transfer catalyst in a diluent.

Claims

1. Process for the preparation of ureas of the formula ##STR4## in which R₁ and R₂ independently of one another denote hydrogen, a linear, branched or cyclic alkyl group which is unsubstituted or substituted by groups inert under the conditions of the reaction, or an aralkyl group, or R₁ and R₂, together with the nitrogen atom, denote a non-aromatic, heterocyclic ring and R₃ denotes an alkyl group which is unsubstituted or substituted by groups inert under the conditions of the reaction, the tertiary butyl group being excluded, comprising N-alkylating a urea of the formula ##STR5## in which R₁ and R₂ have the abovementioned meaning in the presence of a solid base and in the presence of a phase transfer catalyst in a diluent at temperature of 0°

to 150°

C. with an alkylating agent of the formula

space="preserve" listing-type="equation">(R.sub.3).sub.n -X III

in which R₃ has the meaning indicated above and n denotes the numbers 1 or 2, X representing a sulfonic acid or bisulfate group in the event that n denotes the number 1, and X representing a sulfate group in the event than n denotes the number 2.

2. Process according to claim 1, comprising employing

a urea of the formula II in which R₁ and R₂ independently of one another denote hydrogen or an unsubstituted, linear or branched alkyl group having 2 to 18 C atoms, or R₁ and R₂, together with the nitrogen atom, denote a pyrrolidine, piperidine or morpholine ring.

3. Process according to claim 1 comprising employing as base a solid alkali metal hydroxide with or without the addition of 2 to 20 mol % of a solid alkali metal carbonate, relative to the alkali metal hydroxide.

4. Process according to claim 1 comprising employing 1.5 to 8 mol of the solid base per mole of urea of the formula II.

5. Process according to claim 1 comprising employing a quaternary ammonium salt as the phase transfer catalyst.

6. Process according to claim 1 comprising employing an aromatic hydrocarbon as the diluent.

7. Process according to claim 1 comprising employing dimethyl sulfoxide as the diluent and as the catalyst.

8. Process according to claim 1 comprising carrying out the reaction at the reflux temperature of the diluent, unless dimethyl sulfoxide is employed as the diluent.

9. Process according to claim 1 comprising employing an alkylating agent of the formula III in which R₃ denotes a linear or branched, unsubstituted alkyl group and X denotes a 4-toluenesulfonate, methylsulfonate or sulfate group.

10. Process according to claim 1 comprising employing the urea of the formula II and the alkylating agent of the formula III in an equimolar ratio.