The Synthetic Routes of 5,6,7,8-TETRAHYDRO-1,6-NAPHTHYRIDINE-2-CARBOXYLATE

The Synthetic Routes of 5,6,7,8-TETRAHYDRO-1,6-NAPHTHYRIDINE-2-CARBOXYLATE: An Overview in the Chemical Industry

5,6,7,8-Tetrahydo-1,6-naphthyrdine-2-carboxylate, also known as TPNC, is an important organic compound widely used in various industrial applications.
It is a key precursor in the synthesis of several pharmaceuticals, dyestuffs, and other organic chemicals.
The synthesis of TPNC has been extensively researched in the chemical industry, and several synthetic routes have been developed over the years.
In this article, we will provide an overview of the different synthetic routes available for the synthesis of TPNC.

Historical Background

TPNC was first synthesized in 1913 by the German chemist Carl Friedrich Krauch.
He synthesized the compound by reducing 2-nitro-1,6-naphthalenediamine with metallic sodium in liquid ammonia.
This synthetic route was later improved by the Wurtz-Fittig reaction, which involved the use of a copper wire in the reduction of the nitro group to the amine intermediate.

Synthetic Routes for TPNC

There are several synthetic routes available for the synthesis of TPNC.
Some of the most commonly used routes are outlined below:

1. Reduction of 2-nitro-1,6-naphthalenediamine

This is the earliest known synthetic route for TPNC.
It involves the reduction of 2-nitro-1,6-naphthalenediamine with metallic sodium in liquid ammonia.
This reaction is exothermic, and careful control of the reaction conditions is required to avoid unwanted side reactions.
The reduction can be carried out at temperatures ranging from -78°C to -50°C.
The reduction is complete within 1-2 hours.

2. Reduction of 2-chloro-1,6-naphthalenediamine

This route involves the reduction of 2-chloro-1,6-naphthalenediamine with a reducing agent such as lithium aluminum hydride (LiAlH4) in an ether solvent.
The reaction is carried out at room temperature and takes several hours to complete.

3. Reduction of 2-bromo-1,6-naphthalenediamine

This route involves the reduction of 2-bromo-1,6-naphthalenediamine with a reducing agent such as lithium aluminum hydride (LiAlH4) in an ether solvent.
The reaction is carried out at room temperature and takes several hours to complete.

4. Reduction of 2-(2-chloroethylamino)-1,6-naphthalenediamine

This route involves the reduction of 2-(2-chloroethylamino)-1,6-naphthalenediamine with a reducing agent such as lithium aluminum hydride (LiAlH4) in an ether solvent.
The reaction is carried out at room temperature and takes several hours to complete.

5. Reduction of N-(2-chloroethyl)amine-1,6-naphthalenediamine

This route involves the reduction of N-(2-chloroethyl)amine-1,6-naphthalenediamine with a reducing agent such as lithium aluminum hydride (LiAlH4) in an ether solvent.
The reaction is carried out at room temperature and takes several hours to complete.

6. Reduction of N-(2-hydroxy