PCl3-mediated cyclization: Synthesis at room temperature of N-alkenyl derivatives of perhydro-1,4,5-oxa(and thia)diazepine-3,6-dione and of 6,7-diazaspiro[3.4]octane-5,8-dione

✍ Scribed by Graziano Baccolini; Carla Boga; Umberto Negri

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 186 KB
• Volume: 10
• Category: Article
• ISSN: 1042-7163
• DOI: 10.1002/(sici)1098-1071(1999)10:7<615::aid-hc15>3.0.co;2-p

✦ Synopsis

The use of the PCl 3 /hydrazone/dicarboxylic acid combination can be applied in an efficient one-pot procedure for the synthesis at room temperature of the seven-membered ring compounds, 6 (perhydro-1,4,5-oxadiazepine-3,6-diones) and (perhydro-1,4,5-thiadiazepine-3,6-diones), and of the first reported derivatives of the heterocycle 6,7-diazaspiro [3.4]octane-5,8-dione 8. Compounds 6 and 7, containing an N-alkenyl group, were obtained in good yields using diglycolic and thiadiglycolic acids with PCl 3 and methylhydrazone 1, with use of a high concentration (0.5 M) of the reagents. N-alkenyl derivatives 8 were obtained in the same manner using 1,1cyclobutanedicarboxylic acid. Changing the order of addition of the reagents gave almost identical results. In the case in which the exocyclic double bond can give E,Z-isomers, the exclusive or prevalent formation