(5R/5S)-2,5-Diphenyl-7-[trans-(1R/1S,2S/2R)-2-phenylcyclohexyloxy]-2,3,5,8-tetrahydro-1H-1,2,4-triazolo[1,2-a]pyridazine-1,3-dione-Water (1/1): a Face-Selective Diels-Alder Reaction of 2-Alkoxy-1,3-butadiene

The title compound, C₃₀H₂₉N₃O₃.H₂O, is the final product in the Diels-Alder reaction between a 2-alkoxydiene and a reactive dienophile such as phenyltriazolinedione after recrystallization in methanol. The water molecule forms a hydrogen bond with a carbonyl oxygen atom in one dione molecule and a weaker interaction with an nitrogen atom in a symmetry related molecule forming dimers linked by the water molecule. Atoms in the five-membered ring stemming from the dienophile molecule are related by a non-crystallographic C₂ axis through an N atom.

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