Procedure for the preparation of 2-cyanoimino-1,3-thiazolidine

Patent metadata

Field	Value
Publication number	US-10752600-B2
Application number	US-201615759574-A
Country	US
Kind code	B2
Filing date	Sep 12, 2016
Priority date	Sep 15, 2015
Publication date	Aug 25, 2020
Grant date	Aug 25, 2020

Abstract

The disclosure provides for methods for preparing 2-cyanoimino-1,3-thiazolidine, which is an important building block for the preparation of crop protection active ingredients and pharmaceuticals. To this end, the disclosure provides for more efficient and improved methods of preparing 2-cyanoimino-1,3-thiazolidine.

First claim

The invention claimed is:

1. A method of preparing 2-cyanoimino-1,3-thiazolidine comprising:
i. in at least about 50%, 75%, 90% or 95% water, reacting cyanamide with carbon disulfide in the presence of a base and in the presence of a phase-transfer catalyst to form dimetal N-cyanodithioiminocarbonate;
ii. in a solvent comprising water in combination with aromatic, cyclic or acyclic hydrocarbons, reacting dimetal N-cyanodithioiminocarbonate with a methylating agent to form metal methyl N-cyanodithioiminocarbonate; and
iii. in at least about 50%, 75%, 90% or 95% water, reacting metal methyl N-cyanodithioiminocarbonate with 2-chloroethylammonium hydrochloride to form 2-cyanoimino-1,3-thiazolidine
wherein the method excludes the isolation and/or purification of one or more intermediates from one or more of steps (i), (ii), or (iii).

2. The method of claim 1 , wherein said method excludes the isolation and/or handling of any solid material until the isolation and/or purification of 2-cyanoimino-1,3-thiazolidine from one or more of steps (i), (ii), or (iii).

3. The method of claim 1 , wherein the methylating agent in step (ii) is selected from the group consisting of a dimethyl sulfate, methyl chloride, and methyl bromide.

4. The method of claim 1 , wherein the yield based on cyanamide of 2-cyanoimino-1,3-thiazolidine after steps (i), (ii), and (iii) is about 50 to about 60%.

5. The method of claim 1 , wherein the moles of 2-chloroethylammonium hydrochloride in step (iii) are about 1.0 to about 1.5 times the moles of cyanamide used in step (i).

6. The method of claim 1 , wherein water alone is used as a solvent in step (iii).

7. The method of claim 1 , wherein the pH in step (iii) is adjusted to about 5 to about 9 before addition of 2-chloroethylammonium hydrochloride.

8. The method of claim 1 , wherein the 2-chloroethylammonium hydrochloride is added to the reaction mixture in an amount of up to about 80 weight % or as a solid in step (iii).

9. The method of claim 1 , wherein after the reaction of step (iii) is complete, the 2-cyanoimino-1,3-thiazolidine is cooled to about 0° C. to about 25° C.

10. A method of preparing 2-cyanoimino-1,3-thiazolidine comprising:
i. reacting cyanamide with carbon disulfide in the presence of a sodium hydroxide and methyltrioctylammonium chloride to form disodium N-cyanodithioiminocarbonate;
ii. reacting disodium N-cyanodithioiminocarbonate with dimethyl sulfate to form sodium methyl N-cyanodithioiminocarbonate; and
iii. reacting sodium methyl N-cyanodithioiminocarbonate with 2-chloroethylammonium hydrochloride to form 2-cyanoimino-1,3-thiazolidine;
wherein the method excludes the isolation and/or purification of one or more intermediates from one or more of steps (i), (ii), or (iii).

11. The method of claim 10 , wherein said method excludes the isolation and/or handling of any solid material until the isolation and/or purification of 2-cyanoimino-1,3-thiazolidine from one or more of steps (i), (ii), or (iii).

12. The method of claim 1 , wherein the methylating agent is dimethyl sulfate.

13. The method of claim 1 , wherein water alone is used as a solvent in step (i).

14. The method of claim 12 , wherein the moles of dimethyl sulfate in step (ii) are selected from about 0.9 to about 1.2 times the moles of cyanamide used in step (i).

Assignees

• Bayer Cropscience Lp

Inventors

• Kulkarni Shekhar
• Rivadeneira Eric

Classifications

• C07D417/06

  linked by a carbon chain containing only aliphatic carbon atoms · CPC title

• A01N43/78

  1,3-Thiazoles; Hydrogenated 1,3-thiazoles · CPC title

• C07D277/18 Primary

  Nitrogen atoms · CPC title