Novel intermediate for sweetener with high sweetness and process for producing the same

Abstract

The present invention relates to a 3-substituted-phenyl-3-merthylbutyric acid and 3-substituted-phenyl-3-merthylaldehyde derivatives, which are useful in the production of N-[N-[3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyl]-L-α-aspartyl]-L-phenylalanine 1-methyl ester, which is a sweetener with high sweetening potency.

1 .- 7 . (Canceled)  
     
     
         8 . A process for producing 3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyric acid, which comprises: 
 converting the substituent at the 3-position in the phenyl group of the compound of formula (2) to a hydroxyl group, wherein said compound of formula (2) is obtained by a process comprising    reacting a compound of formula (1) with 3-methylcrotonic acid in the presence of an acid,                          wherein R is a sulfonyl-type-protecting group, and Me is a methyl group.    
     
     
         9 . The process as defined in  claim 8 , wherein said converting the substituent at the 3-position comprises sulfonic acid ester hydrolysis.  
     
     
         10 . A process for producing a 3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyl aldehyde, which comprises: 
 converting a carboxyl group in the 3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyric acid obtained by the process defined in  claim 8 , into a formyl group.    
     
     
         11 . A process for producing a 3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyl aldehyde, which comprises: 
 converting a carboxyl group in the 3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyric acid obtained by the process defined in  claim 9 , into a formyl group.    
     
     
         12 . A process for producing a 3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyl aldehyde, which comprises: 
 converting the 3-substituted-phenyl-3-methylbutyric acid to a hydroxyl group, wherein said compound of formula (2) is obtained by a process comprising    reacting a compound of formula (1) with 3-methylcrotonic acid in the presence of an acid,                          wherein R is a sulfonyl-type-protecting group, and Me is a methyl group;    and converting the carboxyl group thereof into a formyl group.    
     
     
         13 . The process as defined in  claim 12 , wherein said converting the substituent at the 3-position comprises sulfonic acid ester hydrolysis.  
     
     
         14 . A process for producing a N-[N-[3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyl]-L-α-aspartyl]-L-phenylalanine 1-methyl ester, which comprises: 
 reductively alkylating the 3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyl aldehyde obtained by he process as defined in  claim 10  with aspartame.    
     
     
         15 . A process for producing a N-[N-[3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyl]-L-α-aspartyl]-L-phenylalanine 1-methyl ester, which comprises: 
 reductively alkylating the 3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyl aldehyde obtained by he process as defined in  claim 11  with aspartame.    
     
     
         16 . A process for producing a N-[N-[3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyl]-L-α-aspartyl]-L-phenylalanine 1-methyl ester, which comprises: 
 reductively alkylating the 3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyl aldehyde obtained by he process as defined in  claim 12  with aspartame.    
     
     
         17 .- 24 . (Canceled)