The Production Process of 8,11-Imino-3,6:16,13-dinitrilo-1,18-benzodiazacycloeicosine,gadolinium deriv.

8,11-Imino-3,6:16,13-dinitrilo-1,18-benzodiazacycloeicosine, gadolinium deriv.
, also known as Gd-DOTA-Bn-Inamrinone, is an important intermediate in the production of contrast agents for magnetic resonance imaging (MRI).
The compound is synthesized through a multi-step process that involves several chemical reactions.

The production process of Gd-DOTA-Bn-Inamrinone can be broken down into the following steps:

1. Synthesis of DOTA-Bn-Inamrinone
   The first step in the synthesis of Gd-DOTA-Bn-Inamrinone is the preparation of DOTA-Bn-Inamrinone.
   DOTA stands for 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid, which is a chelating agent that can bind to metal ions.
   Bn-Inamrinone is an organic compound that contains a nitroxide group, which is a stable radical that can be used as a precursor for the synthesis of Gd-DOTA-Bn-Inamrinone.
   

The synthesis of DOTA-Bn-Inamrinone typically involves the following steps:

• The preparation of DOTA by a series of chemical reactions, such as the condensation of o-phenylenediamine and benzene-1,4-diamine followed by the removal of the water molecule formed in the reaction.
  
• The synthesis of Bn-Inamrinone, which involves the reduction of 4-nitro-1,2-benzenedicarboxylic acid diethyl ester to form Bn-Inamrinone.
  
• The reaction of DOTA and Bn-Inamrinone in the presence of a suitable catalyst, such as sodium hydroxide, to form DOTA-Bn-Inamrinone.
  

2. Complexation of Gd with DOTA-Bn-Inamrinone
   The next step in the synthesis of Gd-DOTA-Bn-Inamrinone is the complexation of Gd with DOTA-Bn-Inamrinone.
   Gd stands for gadolinium, a rare earth metal that is commonly used as a contrast agent in MRI.
   The complexation of Gd with DOTA-Bn-Inamrinone involves the formation of a stable complex between the gadolinium ion and the DOTA-Bn-Inamrinone molecule.
   

The complexation of Gd with DOTA-Bn-Inamrinone typically involves the following steps:

• The addition of a solution of Gd(NO3)2 in water to a solution of DOTA-Bn-Inamrinone in a suitable solvent, such as dimethylformamide or dimethyl sulfoxide.
  
• The addition of a reducing agent, such as Na2S2O4, to the reaction mixture to reduce the Gd(III) ion to Gd(II) ion.
  
• The reaction of the reduced Gd(II) ion with DOTA-Bn-Inamrinone to form the Gd-DOTA-Bn-Inamrinone complex.
  

3. Purification of Gd-DOTA-Bn-Inamrinone
   The final step in the synthesis of Gd-DOTA-Bn-Inamrinone is the purification of the synthesized complex.
   The purification step is important to remove any impurities that may have been introduced during the previous steps.
   

The purification of Gd-DOTA-Bn-Inamrinone typically involves the following steps:

• The isolation of the Gd-DOTA-Bn-Inamrinone complex by column chromatography on a suitable stationary phase, such as silica gel or alumina.
  
• The elution of the Gd-DOTA-Bn-Inamrinone complex from the column using a suitable el