Browse Prior Art Database

Preparation of Cloquintocet Acid

IP.com Disclosure Number: IPCOM000246305D
Publication Date: 2016-May-26
Document File: 2 page(s) / 140K

Publishing Venue

The IP.com Prior Art Database

Abstract

This paper reports a process for preparation of (5-chloroquinolin-8-yloxy)acetic acid, known commercially as cloquintocet, cloquintocet acid, or CQC acid in short. CQC acid is a crop safener that is added to various herbicide formulations to reduce crop damage by herbicides.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 51% of the total text.

Page 01 of 2

Preparation of Cloquintocet Acid

This paper reports a process for preparation of (5-chloroquinolin-8-yloxy)acetic acid, known commercially as cloquintocet, cloquintocet acid, or CQC acid in short. CQC acid is a crop safener that is added to various herbicide formulations to reduce crop damage by herbicides (Figure 1).

Figure 1. Structures of CQC acid and CQC ester

CQC acid was typically prepared by hydrolysis of a CQC ester (such as 2-methylhexyl ester) under acidic conditions with subsequent addition of a base,1, 2 or under basic conditions with subsequent acidification.3 CQC esters were prepared from 5-chloro-quinolin-8-ol and an alkyl 2-chloroacetate (such as 2-methylhexyl 2-chloroacetate).1, 2 The reported process involved (i) use of a mixture of bases, NaOH and Na2CO3, (ii) use of a mixture of organic solvents, N-methylpyrrolidinone (NMP) and toluene, and (iii) removal of water by azeotropic distillation.

Pursuant to this disclosure, the synthesis of CQC acid is accomplished in a one-pot fashion starting from 5-chloro-quinolin-8-ol and methyl 2-chloroacetate (Figure 2). The preparation of CQC methyl ester features use of a single organic solvent (DMSO), use of a single base (NaOH), and removal of water by distillation under reduced pressure. The hydrolysis of resulting CQC methyl ester is achieved by using catalytic amount of an acid (0.1 N HCl or 0.1 N H2SO4). CQC acid is obtained in high yield (90-97%).

Figure 2. Synthesis of CQC acid

Followed is a detailed description of preparing CQC acid.


Page 02 of 2

To a 500-mL three-neck round bottom flask equipped with an overhead stirrer, a thermometer and a cold water condenser under nitrogen atmosphere, were loaded 5-chloroquinolin-8-ol (35.92 g, 200.0 mmol) and dimethyl sulfoxide (DMSO, 100 mL). The reaction flask was heate...