Field of the invention
The present invention provides a process for the preparation of a compound of Formula I.

Formula I
whereinR1 is C1-C12haloalkyl.

Background of the invention
The compounds of Formula I are valuable intermediates for producing active pharmaceutical ingredients and agrochemicals. The US Patent No. 6,777,556 provides a process of preparation of compound of Formula V by hydrolysing a compound of Formula IV in the presence of a base and organic solvent. The compound of Formula V has a haloalkyl substitution at para position to the carboxylic acid group.

Formula V
wherein R1 is C1-C12 haloalkyl and R6 is M or Hydrogen, where M is one equivalent of analkali metal or half an equivalent of alkaline earth metal.

Formula IV
wherein R1 is C1-C12 haloalkyl and R5 is C1-C12 alkyl

The described process suffers from the drawback that the use of solvent results in effluent generation, that is, presence of organic solvent in water.It is a well-known fact that the effluents containing organic solvent in water has to be treated first before disposing as compared to water as effluent, wherein no treatment is required. Also, use of solvent adds on to the cost thereby making the process industrially unfavourable.

The present invention provides a novel process for preparation of compound of Formula I, wherein the haloalkyl group is at ortho position to the carboxylic acid group. The process of the present invention is environment-friendly as it is carried out in the absence of any organic solvent.

While working on the present invention, the inventors have surprisingly observed that, carrying out the hydrolysis of compound of Formula IIwithout using organic solvent results in considerable reduction in reaction time completion as compared to the prior art. Thus, present invention provides a simple, environment-friendly, economical and industrially feasible process.

Object of the invention
The main object of the present invention is to provide a process for the preparation of a compound of Formula I

Formula I
wherein R1 is C1-C12haloalkyl

Summary of the invention
The present invention provides a process for the preparation of a compound of Formula I, comprising:
a) hydrolysing a compound of Formula II in the presence of a base or an acid to obtain a compound of Formula I, and
b) isolating the compound of Formula I obtained from step a), wherein the step a) is carried out in the absence of organic solvent.

Formula II
wherein R2 is H or C1-C12 alkyl and R1 is C1-C12haloalkyl

Formula I
wherein R1 is as defined above.

The present invention also provides a process for the preparation of a compound of Formula I, comprising:
a) hydrolysing a compound of Formula II in the presence of a base or an acid to obtain a compound of Formula I, and
b) isolating the compound of Formula I obtained from step a).

Formula II
wherein R2 is H or C1-C12 alkyl and R1 is C1-C12haloalkyl.

Formula I
wherein R1 is as defined above.

Detailed description of the invention
In an aspect, the present invention provides a process for the preparation of a compound of Formula I, comprising:
a) hydrolysing a compound of Formula II in the presence of a base or an acid to obtain a compound of Formula I, and
b) isolating the compound of Formula I obtained from step a), wherein the step a) is carried out in the absence of organic solvent.

Formula II
wherein R2 is H or C1-C12 alkyl and R1 is C1-C12haloalkyl.

Formula I
wherein R1 is as defined above.

In another aspect, the present invention provides a process for the preparation of a compound of Formula I, comprising:
a) hydrolysing a compound of Formula II in the presence of a base or an acid to obtain a compound of Formula I, and
b) isolating the compound of Formula I obtained from step a).

Formula II
wherein R2 is H or C1-C12 alkyl andR1 is C1-C12haloalkyl.

Formula I
wherein R1 is as defined above.

The compound of Formula IImay be obtained commercially or may be prepared by any method known in the art, for example, US Patent Application No. 2010/0292482.

The step a) is carried out in the presence of a base selected from sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide,lithium hydroxide, rubidium hydroxide, cesium hydroxide, magnesium hydroxide, strontium hydroxide, beryllium hydroxideand mixture thereof.The step a) is carried out in the presence of an acid selected from hydrochloric acid, hydrobromic acid, sulfuric acid, acetic acid and mixture thereof.

The step a) may take placeat a temperature in the range of about 20°C to 100°C and for about1 hourto 10 hours.The organic solvent is any solvent other than water.

The compound of Formula I is isolated by any of the methods known in the art, for example, neutralization in the presence of an acid. The acid used for neutralization is selected from hydrochloric acid, hydrobromic acid, sulfuric acid andacetic acid or mixture thereof.

The term ‘about’ refers to a variation of 10% on the higher and lower side of specified parameter.

While the present invention has been described in terms of its specific embodiments, certain modifications and equivalents will be apparent to those skilled in the art and are intended to be included within the scope of the present invention.

The following examples are given by way of illustration and therefore should not be construed to limit the scope of the present invention.

Examples
Example 1: Preparation of 2-trifluoromethylpyridine-3-carboxylic acid
In a 250ml flask, sodium hydroxide solution (310 g, 7 %) and ethyl 2-trifluoromethyl nicotinate (100g) were taken. The temperature of the reaction mass was raised to 100°C and was maintained for 1 hours. The progress of the reaction was monitored by gas chromatography. After 99% conversion, the reaction mass was cooled and neutralized with hydrochloric acid (61 g, 30 %). It was then filtered and washed with water to obtain title compound.
Yield (%) = 97
Purity (%) = 99.5

WE CLAIM:
1. A process for the preparation of a compound of Formula I, comprising:
a) hydrolysing a compound of Formula II in the presence of a base or an acid to obtain a compound of Formula I, and
b) isolating the compound of Formula I obtained from step a), wherein the step a) is carried out in the absence of organic solvent.

Formula II

Formula I
wherein R2 is H or C1-C12 alkyl and R1 is C1-C12haloalkyl.
2. A process for the preparation of a compound of Formula I, comprising:
a) hydrolysing a compound of Formula II in the presence of a base or an acid to obtain a compound of Formula I, and
b) isolating the compound of Formula I obtained from step a)

Formula II

Formula I
wherein R2 is H or C1-C12 alkyl and R1 is C1-C12haloalkyl.

3. The process as claimed in claim 1 or 2, wherein the step a) is carried out in the presence of a base selected from the group consisting of sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, lithium hydroxide, rubidium hydroxide, cesium hydroxide, magnesium hydroxide, strontium hydroxide and beryllium hydroxide or a mixture thereof.

4. The process as claimed in claim 1 or 2, wherein the step a) is carried out in the presence of an acid selected from the group consisting of hydrochloric acid, hydrobromic acid, sulfuric acid and acetic acid or a mixture thereof.

5. The process as claimed in claim 1 or 2, wherein the step a) is carried out at a temperature selected in the range of 20°C to 100°C.

6. The process as claimed in claim 1 or 2, wherein the step a) is carried out within a time period of 1 hour to 10 hours.

7. The process as claimed in claim 2, wherein theorganic solvent is other than water.