作者:Manuela Meusel、Agnieszka Ambrożak、Thomas K. Hecker、Michael Gütschow
DOI:10.1021/jo020761f
日期:2003.6.1
5-tetrasubstituted hydantoin 5c, respectively. Alkylation of 4a-s afforded 1,3,5,5-tetrasubstituted hydantoins 5a-h. Mechanisms that explain the transformation of corresponding aminobarbituric acids to hydantoins 4a-s and 5c were discussed in terms of the formation of ring-opened intermediates. Aminobarbituric acids 3a-s unsubstituted at position 3 underwent a ring contraction via intermediate isocyanates