Reaction of 1-Methoxycarbonyl-2-imidazolidinone and Its Derivatives with Nucleophiles

Abstract

The title reactions have been studied in relation to elucidation of the functions of the biotinyl prosthetic group in enzymatic carboxylations promoted by biotin-enzymes. The patterns of the title reactions depend strongly upon the nature of substituents on the imidazolidinone ring and the structure of nucleophiles employed. In the reaction with butylamine, the following patterns were disclosed. (1) For 1-methoxycarbonyl-2-imidazolidinone E1 a 1 the reaction leading to the open-chain product C_2C a J predominates; the reaction takes place at the carbonyl carbon in the imidazolidinone ring (U mode attack). (2) For 1- cetyl-2-imidazolidinone 14 d D, two types of reactions, namely the U mode attack and the nucleophilic attack at the acetyl carbonyl carbon, take place simultaneously. (3) For 3-substituted 1-methoxycarbonyl-2-imidazolidinones substituents; C61-15, COOCH₃, COCH, the U mode attack is no longer observed. The attack at the carbonyl carbon of the substituents at the 1- and 3-positions predominates instead. (4) The U mode attack is observable only when the 2-imidazolidinone ring bears electronwithdrawing substituents such as acetyl and methoxycarbonyl groups at the 1- or 3-position. (5) For 1-methoxycarbonyl-cis-perhydrocyclopenta [d] imidazol-2-one C7 a 1 the attack at the carbonyl carbon of the 1-methoxycarbonyl group predominates, in contrast to the reaction of 1 a D. (6) The U mode attack occurs through an isocyanatte intermediate. On the other hand, in the case of the reactions of Cl a and its derivatives with sodium benzenethiolate, the attack at the methyl carbon of the methoxycarbonyl group occurs perferentially to other modes of the reactions. These results are discussed in terms of the structural features of substituents and also of the reaction mechanisms.