The Synthetic Routes of Methyl 7-isoquinolinecarboxylate

Methyl 7-isoquinolinecarboxylate, also known as methyl 7-hydroxy-2H-pyrrolo[2,3-d]pyrimidine-5-carboxylate, is an important intermediate in the synthesis of various chemicals, pharmaceuticals, and agrochemicals.
This molecule has a complex, heterocyclic structure, which makes its synthesis a challenging task.
Several synthetic routes have been developed over the years for the synthesis of methyl 7-isoquinolinecarboxylate, which will be discussed in this article.

1. The classic route involves the condensation of safranin O with meta-chloroperoxybenzoic acid (mCPB) followed by hydrolysis of the resulting intermediate.
   The reaction proceeds in two steps, first the condensation of safranin O with mCPB to form a benzoic acid derivative, followed by hydrolysis to yield 7-isoquinolinecarboxylate.
   This route offers good yield, but it involves the use of hazardous reagents, such as mCPB.
   
2. Another route involves the condensation of 1,4-benzoxazepine with 4-fluorobenzaldehyde in the presence of a base and subsequent treatment with hydrochloric acid.
   The reaction product is then hydrolyzed to yield the desired product.
   This route offers good yield and is safer compared to the classical route, but it is more complex and requires specialized equipment.
   
3. A more recent route involves the use of a Pd-catalyzed condensation of 2-fluoro-6-methylbenzoxazepine with piperidine-4-carboxaldehyde in the presence of a base.
   The reaction product is then treated with hydrochloric acid to yield the desired product.
   This route is safer and more efficient than the classical route, and it does not require the use of hazardous reagents.
   
4. Another route involves the synthesis of the isoquinoline core of the molecule, followed by the installation of the carboxylate group.
   This route involves the condensation of a range of different isoquinolines with an appropriate carboxylic acid, followed by hydrolysis of the resulting intermediate.
   This route is versatile and allows the synthesis of a wide range of isoquinoline-based compounds.
   

In conclusion, methyl 7-isoquinolinecarboxylate is an important intermediate in the synthesis of various chemicals, pharmaceuticals, and agrochemicals.
Several synthetic routes have been developed over the years for the synthesis of methyl 7-isoquinolinecarboxylate, including the classic route, the route involving 1,4-benzoxazepine and 4-fluorob