Process for the preparation of thieno [3,2-c] pyridine and thieno [2,3-c] py

Claim 2

Process for the preparation of a compound selected from the group consisting of thieno[3,2-c]pyridine and thieno [2,3-c]-pyridine, comprising cyclizing a compound selected from the group consisting of a N-(3,thienyl)methyl-N-[2,2-(OR) 2 ]ethyl-para-toluene sulfonamide and a N-(2-thienyl)-methyl-N-[2,2-(OR) 2 ]-ethyl-para-toluene sulfonamide, respectively, in which the radicals R, when taken individually, are lower alkyls and, when taken together in (OR) 2 , may also form a group selected from the 2- and 3-membered alkylene groups, by treatment with a strong mineral acid in the presence of an inert organic solvent at a temperature between about 50°C and the boiling temperature of the mixture.

Claim 3

Process as claimed in claim 1, wherein the strong mineral acid is selected from the group consisting of hydrochloric, hydrobromic and sulfuric acids.

Claim 4

Process as claimed in claim 1, wherein the inert organic solvent is selected from the group consisting of dioxane, ethanol, isopropanol and butanol.

Claim 5

Process for the preparation of thieno[3,2-c]-pyridine which comprises the steps of: 1. reacting 3-bromomethyl-thiophene with N-[2,2-(OR) 2 ]-ethyl-para-toluene sulfonamide, in which the radicals R, when taken individually, are lower alkyls and when taken together in (OR) 2 , may also form a group selected from the 2- and 3-membered alkylene groups, in the presence of ethanol under reflux to obtain N-(3-thienyl)- methyl-N-[2,2-(OR) 2 ]-ethyl-para-toluene sulfonamide; 2. cyclizing the resulting compound by treatment with a strong mineral acid in the presence of an inert solvent at a temperature between about 50°C and the boiling temperature of the mixture.

Claim 6

Process for the preparation of thieno[3,2-c]-pyridine which comprises the steps of: 1. reacting 3-bromomethyl-thiophene with N-[2,2-(OR) 2 ]-ethyl-para-toluene sulfonamide, in which the radicals R, when taken individually, are lower alkyls and when taken together in (OR) 2 , may also form a group selected from the 2- and 3-membered alkylene groups, in the presence of ethanol under reflux to obtain N-(3-thienyl)- methyl-N-[2,2-(OR) 2 ]-ethyl-para-toluene sulfonamide; 2. cyclizing the resulting compound by treatment with a strong mineral acid in the presence of an inert solvent at a temperature between about 50°C and the boiling temperature of the mixture.

Claim 7

Process for the preparation of thieno[3,2-c]-pyridine which comprises the steps of: 1. reacting 3-thienaldehyde with a compound of formula NH 2 --CH 2 --CH(OR) 2 , in which the radicals R, when taken individually, are lower alkyls and when taken together in (OR) 2 may also form a group selected from the 2- and 3-membered alkylene groups, in the presence of benzene under reflux to give the corresponding Schiff base; 2. reducing said Schiff base with sodium borohydride in the presence of ethanol first at room temperature and then under reflux to obtain N-[2,2-(OR) 2 ]-ethyl-(3-thienyl)-methylamine; 3. reacting the compound obtained in step 2 with para-toluene sulfonyl chloride in the presence of chloroform and water at room temperature under stirring to obtain N-(3-thienyl)-methyl-N-[2,2-(OR) 2 ]-ethyl-para-toluene sulfonamide; 4. cyclizing the resulting compound by treatment with a strong mineral acid in the presence of an inert solvent at a temperature between about 50°C and the boiling temperature of the mixture.

Claim 8

Process for the preparation of thieno[3,2-c]-pyridine which comprises the steps of: 1. reacting 3-thienaldehyde with a compound of formula NH 2 --CH 2 --CH(OR) 2 , in which the radicals R, when taken individually, are lower alkyls and when taken together in (OR) 2 may also form a group selected from the 2- and 3-membered alkylene groups, in the presence of benzene under reflux to give the corresponding Schiff base; 2. reducing said Schiff base with sodium borohydride in the presence of ethanol first at room temperature and then under reflux to obtain N-[2,2-(OR) 2 ]-ethyl-(3-thienyl)-methylamine; 3. reacting the compound obtained in step 2 with para-toluene sulfonyl chloride in the presence of chloroform and water at room temperature under stirring to obtain N-(3-thienyl)-methyl-N-[2,2-(OR) 2 ]-ethyl-para-toluene sulfonamide; 4. cyclizing the resulting compound by treatment with a strong mineral acid in the presence of an inert solvent at a temperature between about 50°C and the boiling temperature of the mixture.

Claim 9

Process for the preparation of thieno[2,3-c]-pyridine which comprises the steps of: 1. reacting 2-chloromethyl-thiophene with N-[2,2-(OR) 2 ]-ethyl-para-toluene sulfonamide, in which the radicals R, when taken individually, are lower alkyls and when taken together in (OR) 2 , may also form a group selected from the 2- and 3-membered alkylene groups, in the presence of ethanol under reflux to obtain N-(2-thienyl)-methyl-N-[2,2-(OR) 2 ]-ethyl-para-toluene sulfonamide; 2. cyclizing the resulting compound by treatment with a strong mineral acid in the presence of an inert solvent at a temperature between about 50°C and the boiling temperature of the mixture.

Claim 10

Process for the preparation of thieno[2,3-c]-pyridine which comprises the steps of: 1. reacting 2-chloromethyl-thiophene with N-[2,2-(OR) 2 ]-ethyl-para-toluene sulfonamide, in which the radicals R, when taken individually, are lower alkyls and when taken together in (OR) 2 , may also form a group selected from the 2- and 3-membered alkylene groups, in the presence of ethanol under reflux to obtain N-(2-thienyl)-methyl-N-[2,2-(OR) 2 ]-ethyl-para-toluene sulfonamide; 2. cyclizing the resulting compound by treatment with a strong mineral acid in the presence of an inert solvent at a temperature between about 50°C and the boiling temperature of the mixture.

Claim 11

Process for the preparation of thieno[-2,3-c]-pyridine which comprises the steps of: 1. reacting 2-thienaldehyde with a compound of formula NH 2 --CH 2 --CH(OR) 2 , in which the radicals R, when taken individually, are lower alkyls and when taken together in (OR) 2 may also form a group selected from the 2- and 3-membered alkylene groups, in the presence of benzene under reflux to give the corresponding Schiff base; 2. reducing said Schiff base with sodium borohydride in the presence of ethanol first at room temperature and then under reflux to obtain N-[2,2-(OR) 2 ]-ethyl-(2-thienyl)-methylamine; 3. reacting the compound obtained in step 2 with para-toluene sulfonyl chloride in the presence of chloroform and water at room temperature under stirring to obtain N-(2-thienyl)-methyl-N-[2,2-(OR) 2 ]-ethyl-para-toluene sulfonamide; 4. cyclizing the resulting compound by treatment with a strong mineral acid in the presence of an inert solvent at a temperature between about 50°C and the boiling temperature of the mixture.

Claim 12

Process for the preparation of thieno[-2,3-c]-pyridine which comprises the steps of: 1. reacting 2-thienaldehyde with a compound of formula NH 2 --CH 2 --CH(OR) 2 , in which the radicals R, when taken individually, are lower alkyls and when taken together in (OR) 2 may also form a group selected from the 2- and 3-membered alkylene groups, in the presence of benzene under reflux to give the corresponding Schiff base; 2. reducing said Schiff base with sodium borohydride in the presence of ethanol first at room temperature and then under reflux to obtain N-[2,2-(OR) 2 ]-ethyl-(2-thienyl)-methylamine; 3. reacting the compound obtained in step 2 with para-toluene sulfonyl chloride in the presence of chloroform and water at room temperature under stirring to obtain N-(2-thienyl)-methyl-N-[2,2-(OR) 2 ]-ethyl-para-toluene sulfonamide; 4. cyclizing the resulting compound by treatment with a strong mineral acid in the presence of an inert solvent at a temperature between about 50°C and the boiling temperature of the mixture.