Process for preparing 2-carboalkoxy-1-indanones

Abstract

A process for the preparation of 2-carboalkoxy-1-indanones of Formula I from 1-indanones of Formula II using a dialkyl carbonate and an alkali metal alkoxide is provided. This process is superior to the prior art in that it avoids pyrophoric reagents such as sodium hydride, and proceeds in high chemical yield and product quality. The invention provides a novel process to an important intermediate in the preparation of arthropodicidal carboxanilides of commercial interest. ##STR1## wherein: R 1 , R 2 and M are defined in the specification.

What is claimed is: 
     
       1. The process for the preparation of a 2-carboalkoxy-1-indanone of Formula I: ##STR4## comprising reacting a 1-indanone of Formula II ##STR5## with at least one molar equivalent of a dialkyl carbonate of the formula (R 2  O) 2  C=O in an aprotic solvent in the presence of a base MOR 2  and removing alcohol R 2  OH by distillation as it is formed from the reaction of the indanone of Formula I with the dialkyl carbonate wherein:   R 1  is selected from the group H, R 3 , C 2  -C 6  alkoxyalkyl, C 2  -C 6  alkylthioalkyl, C 3  -C 6  cycloalkyl, C 3  -C 6  fluorocycloalkyl, halogen, OR 3 , SR 3 , S(O)R 3 , S(O) 2  CF 3 , S(O) 2  CF 2  R 3 , OS(O) 2  R 3  ; CO 2  R 2 , NR 3  R 4 , NO 2 , phenyl optionally substituted with 1 to 3 substituents independently selected from R 5  and benzyl optionally substituted with 1 to 3 substituents independently selected from R 5  ;   R 2  is C 1  -C 6  alkyl;   R 3  is selected from the group C 1  -C 6  alkyl, and C 1  -C 6  fluoroalkyl;   R 4  is C 1  -C 4  alkyl;   R5 is selected from the group halogen, NO 2 , C 1  -C 2  alkyl, C 1  -C 2  fluoroalkyl, C 1  -C 2  alkoxy C 1  -C 2  fluoroalkoxy, C 1  -C 2  alkylthio, C 1  -C 2  fluoroalkylthio, SO 2  CF 3 , SO 2  CF 2  R 3 , and   M is an alkali metal.   
     
     
       2. A process of claim 1 wherein R 1  is Cl at the 5-position, R 2  is CH 3 , and M is Na. 
     
     
       3. A process of claim 1 wherein the aprotic solvent is selected from aromatic hydrocarbons, chlorobenzene, dichlorobenzenes, aliphatic hydrocarbons and dialkyl carbonates. 
     
     
       4. A process of claim 3 wherein the aprotic solvent is selected from toluene, xylenes, chlorobenzene, heptane and dimethyl carbonate. 
     
     
       5. A process of claim 4 wherein R 1  is Cl at the 5-position, R 2  is CH 3  and M is Na. 
     
     
       6. A process of claim 5 wherein the alcohol R 2  OH is removed by continuous fractional distillation.