Domino Reactions of 1,2-Diimidoyl-1,2-dichloroethanes. Synthesis of 3-Imino-1,2-dithia-3<i>H</i>-cyclopent-4-enes, 3-Amino-2-thioxo-2,5<i>H</i>-pyrrol-5-ones, 2,3-Diamino-4-thioxo-4<i>H</i>-thiopyrans, and 6-Imino-6<i>H</i>-1,3-oxazines

The reaction of mono- and dilithiated ethyl thioglycolate with 1,2-diimidoyl-1,2-dichloroethanes, aza-analogues of oxalyl chloride, afforded (depending on the reaction conditions) 3-imino-1,2-dithia-3H-cyclopent-4-enes, 3-amino-2-thioxo-2,5H-pyrrol-5-ones, and 2,3-diamino-4-thioxo-4H-thiopyrans. The reaction of the dianion of ethyl hippurate with 1,2-diimidoyl-1,2-dichloroethanes afforded 6-imino-6H-1,3-oxazines.