Fluorescent probes

Abstract

A compound represented by the formula (I) wherein R 1 and R 2 represent amino groups that substitute at adjacent positions on the benzene ring, wherein one of the amino groups may have one alkyl group; R 3 and R 4 represent hydrogen atom, a C 1-6 alkyl group, or a C 1-6 alkoxy group, R 5 and R 8 independently represent a C 1-6 alkyl group, R 6 and R 9 represent a carboxy-substituted C 1-6 alkyl group, an alkoxycarbonyl-substituted C 1-6 alkyl group, a sulfo-substituted C 1-6 alkyl group, or an alkyl sulfonate-substituted C 1-6 alkyl group, and R 7 and R 10 represent a C 1-6 alkyl group, an aryl group, a C 1-6 alkoxycarbonyl group, a vinyl group, a thienyl group, or a pyrrolyl group, and an agent for measurement of nitrogen monoxide containing the compound. Said compound can give a fluorescent substance that is free from change in fluorescence intensity in a wide pH range.

1 . A compound represented by the following formula (I):  
     
       
         
         
             
             
         
       
     
     wherein, R 1  and R 2  represent amino groups that substitute at adjacent positions on the benzene ring, wherein one of the amino groups may have one alkyl group which may be substituted; R 3  and R 4  independently represent hydrogen atom, a C 1-6  alkyl group, or a C 1-6  alkoxy group, R 5  and R 8  independently represent a C 1-6  alkyl group which may be substituted, R 6  and R 9  independently represent a carboxy-substituted C 1-6  alkyl group, an alkoxycarbonyl-substituted C 1-6  alkyl group, a sulfo-substituted C 1-6  alkyl group, or an alkyl sulfonate-substituted C 1-6  alkyl group, and R 7  and R 10  independently represent a C 1-6  alkyl group which may be substituted, an aryl group which may be substituted, a C 1-6  alkoxycarbonyl group which may be substituted, a vinyl group which may be substituted, a thienyl group which may be substituted, or a pyrrolyl group which may be substituted, or a salt thereof.  
   
   
       2 . The compound or a salt thereof according to  claim 1 , wherein R 6  and R 9  are 2-carboxy-1-ethyl groups, and R 5 , R 7 , R 8 , and R 10  are methyl groups.  
   
   
       3 . The compound or a salt thereof according to  claim 1 , wherein R 6  and R 9  are 2-methoxycarbonyl-1-ethyl groups, and R 5 , R 7 , R 8 , and R 10  are methyl groups.  
   
   
       4 . An agent for measurement of nitrogen monoxide comprising the compound or a salt thereof according to  claim 1 .  
   
   
       5 . A compound represented by the following formula (II):  
     
       
         
         
             
             
         
       
     
     wherein, R 11  and R 12  combine together to represent a group represented by —N═N—NR 30 — which forms a ring structure at adjacent positions on the benzene ring wherein R 30  represents hydrogen atom, or an alkyl group which may be substituted, or R 11  and R 12  represent a combination of an amino group (which may have an alkyl group which may be substituted or a protective group for amino group) and nitro group that substitute at adjacent positions on the benzene ring; R 13  and R 14  independently represent hydrogen atom, a C 1-6  alkyl group, or a C 1-6  alkoxy group, R 15  and R 18  independently represent a C 1-6  alkyl group which may be substituted, R 16  and R 19  independently represent a carboxy-substituted C 1-6  alkyl group, an alkoxycarbonyl-substituted C 1-6  alkyl group, a sulfo-substituted C 1-6  alkyl group, or an alkyl sulfonate-substituted C 1-6  alkyl group, and R 17  and R 20  independently represent a C 1-6  alkyl group which may be substituted, an aryl group which may be substituted, a C 1-6  alkoxycarbonyl group which may be substituted, a vinyl group which may be substituted, a thienyl group which may be substituted, or a pyrrolyl group which may be substituted, or a salt thereof.  
   
   
       6 . The compound or a salt thereof according to  claim 5 , wherein R 16  and R 19  are 2-carboxy-1-ethyl groups, and R 15 , R 17 , R 18 , and R 20  are methyl groups.  
   
   
       7 . The compound or a salt thereof according to  claim 5 , wherein R 16  and R 19  are 2-methoxycarboxy-1-ethyl groups, and R 15 , R 17 , R 18 , and R 20  are methyl groups.  
   
   
       8 . A method for measurement of nitrogen monoxide, which comprises the steps of: 
 (a) reacting a compound represented by the formula (I) according to  claim 1  with nitrogen monoxide; and    (b) detecting a compound represented by the formula (II) according to the following formula (II):                          wherein, R 11  and R 12  combine together to represent a group represented by —N═N—NR 30 — which forms a ring structure at adjacent positions on the benzene ring wherein R 30  represents hydrogen atom, or an alkyl group which may be substituted, or R 11  and R 12  represent a combination of an amino group (which may have an alkyl group which may be substituted or a protective group for amino group) and nitro group that substitute at adjacent positions on the benzene ring; R 13  and R 14  independently represent hydrogen atom, a C 1-6  alkyl group, or a C 1-6  alkoxy group, R 15  and R 18  independently represent a C 1-6  alkyl group which may be substituted, R 16  and R 19  independently represent a carboxy-substituted C 1-6  alkyl group, an alkoxycarbonyl-substituted C 1-6  alkyl group, a sulfo-substituted C 1-6  alkyl group, or an alkyl sulfonate-substituted C 1-6  alkyl group, and R  17  and R 20  independently represent a C 1-6  alkyl group which may be substituted, an aryl group which may be substituted, a C 1-6  alkoxycarbonyl group which may be substituted, a vinyl group which may be substituted, a thienyl group which may be substituted, or a pyrrolyl group which may be substituted, or a salt thereof, produced in the aforementioned step (a) wherein R 11  and R 12  combine together to form a group represented by —N═N—NR 30 — which forms a ring structure at adjacent positions on the benzene ring wherein R 30  represents hydrogen atom, or an alkyl group which may be substituted.    
   
   
       9 . An agent for measurement of nitrogen monoxide comprising the compound or a salt thereof according to  claim 2 .  
   
   
       10 . An agent for measurement of nitrogen monoxide comprising the compound or a salt thereof according to  claim 3.