Imidazole 4- amino-5-ethoxycarbonyl

Trifluoromethylphenyl)sulfonylethoxy-carbonyl group (Tsc), 2-(4-trifluoromethyl-phenylsulfonyl)ethoxycarbonyl, a base-labile protection group for amines, especially suited for the heteroaromatic pyrrole and imidazole amino acids Trp and His. The Tsc group differs from the 9-fiuorenylmethoxycarbonyl (Fmoc) group in decreased sensitivity toward premature cleavage [J. S. Choi et al., Tetrahedron 2005, 61, 2493]. 

Enzymes modified with N -carbonyldiimidazole (CDI) include horseradish peroxidase 761 /1-lactamase after nitration and reduction,[771 lysozyme, and urease.[781 Ref. [77] describes how the tyrosine side chain of a protein was nitrated, reduced with dithionite to an amino group, and then treated with CDI or A/-(2,2,2-trifluoro-ethoxycarbonyl)imidazole to give the benzoxazolinonyl alanine moiety ... 

Amino-5(4)-ethoxycarbonyl-imidazol wird mit Formaldehyd/Dimethylamin nicht an der Amino-Gruppe, sondern am Ring-C-Atom in 2-Stellung zu 4(5)-Amino-2-(dimethylamino-methyl)-5(4)-ethoxycarbonyl-imidazol 1-amino-alkyliert762. 

Nach dieser Methode ist auch die Herstellung von 5(4)-Aminosulfonyl-4(5)-ethoxycarbonyl-amino-imidazol (72%) aus 4(5)-Aminosulfonyl-5(4)-hydrazinocarbonyl-imidazol moglich1060, Der in der Lit,1000 beschriebene Austausch der 4(5)-Carboxy- bzw. 4(5)-Ethoxycarbonyl-Grup-pe an mit Formaldehyd gegen eine Hydroxymethyl-Gruppe konnte in eigenen Versuchen nicht reproduziert werden. 

Aus 2,4(5)-Difluor-5(4)-ethoxycarbonyl-imidazol erhalt man durch selektive Substitution des Fluor-Atoms in 2-StelIung mit Ammoniak in Methanol 2-Amino-5(4)-ethoxycarbonyl-4(5)-fluor-imidazol in 65% Ausbeute928. 

Imidazol 5-Amino-4-aminocarbonyl-l-(4-ethoxycarbonyl-butyl)- E8c, 24 [NC-CH(NH2)-CO-NH2 + HC(OR)3/H2N-A-COOR]... 

A novel approach to adenine and hypoxanthine derivatives involves a high-temperature intramolecular cyclization of 4(5)-substituted-amino-5(4)-unsubstituted-imidazole intermediates. For example, reaction of 1,2-dimethylimidazol-5-amine with (ethoxymethylene)urethane gives the Af -ethoxycarbonyl-jV -(imidazol-5-yl)formimidamide which under thermal cyclization is rapidly transformed into 8,9-dimethylhypoxanthine (3). 

Reaction of 5-amino-l -benzyl-4-imidazolecarboxylic acid 495 with 2,4,6-tris(ethoxycarbonyl)-1,3,5-triazine 496 at 80 °C in DMF led to 9-benzyl-2,6-bis(ethoxycarbonyl)purine 501 in 83% yield. Presumably, 5-amino-l-benzyM-imidazole 497 is generated siVu from the acid and is highly reactive for the cycloaddition. The cycloadduct 498 then spontaneously undergoes retro Diels-Alder reaction with the loss of ethyl cyanoformate 499 followed by the loss of ammonia and aromatization to produce the purine in a regioselective manner (Scheme 114) <1999JA5833, 2005JOC998>. 

Heating equimolar amounts of 5-amino-l-methylimidazole-2(3//)-thione (391) with diethyl ethoxymethylenemalonate (390) gave the diethyl ester of [(5-amino-2,3-dihydro-1-methyl-2-thioxo-lH-imidazol-4-yl)methylene]propanedioic acid (392), which cyclized in 10% aqueous sodium hydroxide to 6-ethoxycarbonyl-3-methyl-2(lH)-thioxoimidazo[4,5-fc]pyridin-5(4//)-one (393) (78H(10)24l). 

Single crystals of ionic liquids with chiral cations have mostly been investigated as racemates, including [l- l-(ethoxycarbonyl)ethyl -3-methylimidazolium][NTf2] (mpt. 45°C) [138], [1-(2-hydroxy-2-methyl-2-phenylethyl)-3-tert-butylimidazolium]Cl (mpt. 64-66°C) [217], [(1-phenylethyl)ammonium][CH2ClC02] (mpt. 95°C) [420], [ l-(2-naphthyl)prop-2-en-l-yl]amino pyridinium]l (mpt. 103-105°C) [485] and [6,6 -spirobi(l-methyl-l,5,6,7-tetrahydropyrrolo[l,2-a]imidazol-4-ium][NTf2]2 (mpt. 112°C Fig. 11.9] [547]. Exceptions... 

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