Rigidized oxazole dyes

Abstract

The quaternary salts of rigidized 1,3-oxazole compounds of the formula: ##STR1## where R is either H or CH 3 O. The compounds are produced in a modif Robinson-Gabriel synthesis of oxazoles. These dyes are used in solution with non-interfering polar solvents, such as ethanol and H 2 O, to form lasing media useful in dye lasers.

What is claimed is: 
     
       1. As a composition of matter 2-(4-N-methylpyridinium)-4,5-dihydronaphtho [2,1-d]-1,3-oxazole p-toluenesulfonate. 
     
     
       2. As a composition of matter 2-(4-N-methylpyridinium)-4,5-dihydro6-methoxynaphtho[2,1-d]-1,3-oxazole p-toluenesulfonate. 
     
     
       3. A method for producing 2-(4-pyridyl)-4,5-dihydro-naphtho[2,1-d]-1,3-oxazole by a modified Robinson-Gabriel synthesis of oxazoles, the improvement comprising the steps: mixing the isonicotinamide of 2-amide-1-tetralone with phosphorus oxychloride;   refluxing said mixture;   removing the excess reagent and isolating a residue;   forming a solution of said residue, ethanol and water;   making said solution said residue, ethanol and water;   making said solution basic by adding a hydroxide; and   precipitating the oxazole by cooling said basic solution and then removing said oxazole.   
     
     
       4. A method of preparing the quaternary salt 2-(4-N-methyl-2-pyridinium)-4,5-dihydro-naphtho[2,1-d]-1,3-oxazole p-toluenesulfonate from 2-(4-pyridyl)-4,5-dihydro-naphtho [2,1-d]-1,3-oxazole comprising the steps: dissolving said oxazole in a solution of dichloroethane and methyl p-toluenesulfonate;   refluxing said solution; and   crystallizing the product by cooling said solution.   
     
     
       5. A method for producing 2-(4-pyridyl)-4,5-dihydro-6-methoxynaphtho[2,1-d]-1,3-oxazole by a modified Robinson-Gabriel synthesis of oxazoles, the improvement comprising the steps: mixing the isonicotinamide of 6-methoxy-2-amino-1-tetralone with phosphorus oxychloride;   refluxing said mixture;   removing the excess reagent and isolating a residue;   forming a solution of basic by adding a hydroxide; and   precipitating the oxazole by cooling said basic solution and then removing said oxazole.   
     
     
       6. A method for producing the quaternary salt 2-(4-N-methylpyridinium)-4,5-dihydro-6-methoxynaphtho[2,1-d]1,3-oxazole p-toluenesulfonate from 2-(4-pyridyl)-4,5-dihydro-6-methoxynaphtho[2,1-d]-1,3-oxazole comprising the steps: dissolving said oxazole in a solution of dichloroethane; and methyl p-toluenesulfonate;   refluxing said solution; and   crystallizing the product by cooling said solution.