The Synthetic Routes of 1,6-DIHYDRO-6-OXO-3-PYRIDAZINECARBOXYLIC ACID, ETHYL ESTER

1,6-Dihydro-6-oxo-3-pyridazincarboxylic acid, ethyl ester is a synthetic compound that is widely used in the chemical industry for various purposes.
This compound is commonly known as DEET, which is an abbreviation of its chemical name.
DEET is an insect repellent that is used to protect against mosquitoes, ticks, and other insects that can transmit diseases.

The synthetic route to DEET involves several steps, which are described below:

Step 1: Preparation of 3-pyridazinedione
The first step in the synthesis of DEET involves the preparation of 3-pyridazinedione, which is a key intermediate.
This compound is prepared by condensing oxalic acid and malonic acid in the presence of sodium hydroxide.
The reaction is carried out in water, and the product is extracted with ether and dried with anhydrous sodium sulfate.
The ether solution is then filtered and concentrated, and the residue is recrystallized from ethanol to obtain pure 3-pyridazinedione.

Step 2: Preparation of 1,6-dihydro-6-oxo-3-pyridazinecarboxylic acid
The next step in the synthesis of DEET involves the preparation of 1,6-dihydro-6-oxo-3-pyridazinecarboxylic acid, which is an intermediate compound.
This compound is prepared by treating 3-pyridazinedione with glycolic acid and sodium hydroxide in a water bath.
The reaction is carried out at a temperature of 70-80°C, and the product is extracted with ether and dried with anhydrous sodium sulfate.
The ether solution is then filtered and concentrated, and the residue is recrystallized from ethanol to obtain pure 1,6-dihydro-6-oxo-3-pyridazinecarboxylic acid.

Step 3: Preparation of DEET
The final step in the synthesis of DEET involves the preparation of the ethyl ester of 1,6-dihydro-6-oxo-3-pyridazinecarboxylic acid.
This compound is prepared by treating 1,6-dihydro-6-oxo-3-pyridazinecarboxylic acid with ethyl bromide in the presence of a solvent such as acetonitrile or DMF.
The reaction is carried out at a temperature of 80-100°C, and the product is extracted with water and then with ethyl acetate.
The organic layer is then washed with brine, dried with anhydrous sodium sulfate, and filtered.
The solvent is then removed under reduced pressure, and the residue is recrystallized from ethanol to obtain pure DEET.

Overall, the synthesis of DEET involves several steps, but the process is relatively straightforward and can be accomplished using standard organic synthesis techniques.
The compound is widely used in the chemical industry and is an important ingredient in insect repellents.