Patent GB-643337-A (GB)
Title: Aminoalkyl derivatives of thiophenes
IPC: C07D333/20
Filed: 1947-07-29
Abstract: Thermoplastic resins and sub-resinous bodies containing the thiophene residue C4HnS (n=0 - 3) are manufactured by condensing, at temperatures between 65 DEG  C. and reflux temperature (e.g. at 75-85 DEG  C.), thiophene or derivatives thereof substituted in the nucleus by stable electropositive groups or atoms (e.g. alkyl or alkoxy groups or halogen atoms, but not the unstable hydroxy or amino groups) with formaldehyde or with polymers thereof in association with a depolymerizing agent therefor (e.g. water or an acid having a dissociation constant not greater than about 10-4), in the presence of one or more of the following nitrogenous compounds: ammonium halides (i.e. chloride, bromide or iodide) and halides of mono- and di-alkylamines, alkyl and aryl polyamines, urea and aniline.  In place of formaldehyde and an ammonium halide there may be used hexamethylenetetramine and a hydrogen halide.  The resins are basic and are obtained in the form of their hydrohalides, which are water-soluble when an ammonium halide has been used, but water-insoluble when prepared from an alkyl or aryl polyamine, urea or aniline.  The sub-resinous bodies yield hard resins on heating or when a film thereof is exposed to the air.  Examples describe the use of ammonium chloride and the hydrochlorides of aniline, urea and ethylenediamine as the nitrogenous compound.ALSO:2-Thenylamines, di-2-thenylamines and subresinous condensation products containing the thiophene reside C4HnS (n=0-3) are manufactured by condensing, at temperatures between 65 DEG  C. and reflux temperature, thiophene or derivatives thereof substituted in the nucleus by stable electropositive groups or atoms (e.g. alkyl or alkoxy groups or halogen atoms but not the unstable hydroxy or amino groups) with formaldehyde or with polymers thereof in association with a depolymerizing agent therefor (e.g. water or an acid having a dissociation constant not greater than about 10-4), in the presence of one or more of the following nitrogenous compounds: ammonium halides (i.e. chloride, bromide or iodide) and halides of mono- and di-alkylamines, alkyl and aryl polyamines, urea and aniline.  In place of formaldehyde and an ammonium halide there may be used hexamethylenetetramine and a hydrogen halide.  The products are obtained in the form of their hydrohalides, from which the free amines may be obtained by treatment with aqueous caustic alkali followed by extraction with benzene from a saturated salt solution. The proportions of the various amines in the products depend on the relative proportions of the three reactants, which may advantageously be 1 mol. of thiophene compound and 1 mol. of formaldehyde to 3 mols. of ammonium chloride.  The products are useful as intermediates in the production of dyes, pharmaceutical compounds and other materials, as antioxidants in lubricating oils and as insecticides.  Examples and tables illustrate the interaction, in various proportions and under various conditions, of the following starting materials: thiophene, amylthiophene; aqueous formaldehyde, paraformaldehyde or trioxymethylene in the presence of acetic acid; ammonium chloride or bromide, dibutylamine hydrochloride; hexamethylenetetramine and hydrochloric acid.  Reference is also made to the use of ethylenediamine and phenylenediamines.ALSO:As corrosion inhibitors, for addition to mineral oils, may be employed mono- and di-2-thenylamine and derivatives thereof substituted in the nucleus by stable electropositive groups or atoms, e.g. alkyl or alkoxy groups or halogen atoms.  These compounds are effective in amounts of 0.06 to 1.0 per cent, as shown by experiments in which mono- and di-2-thenylamine are added to Pennsylvania solvent-refined oil.