5-Chloro Substituted 1,5-Dihydro-2H-pyrrol-2-ones as Intermediates for the Efficient Synthesis of 5-Alkylamino, 5-Azido, 5-Alkoxyamino, and 5-Alkoxy Derivatives - Nikitin, Kirill V; Andryukhova, Nonna P (Synthesis, 2001)