Quinazoline 3,4-dihydro-, spectra

NH group (giving a clearly visible doublet due to J( N, H), i5( NH)= -264.6, second cross-peak belongs to the correlation with aromatic proton from peri position) and nitrogen via jC N, H) from HN-CO-N (i5C N)= -232.0). Third nitrogen correlates with methylene protons of both butyl and benzyl groups (i5( N)= -241.8). (B) Structure of 2-benzyl-1-butyl-2,3-dihydro-imidazo[1,5-c]quinazoline-3,5-dione. (Spectrum taken from Klasek A, Kofistek K, Lycka A, and Holcapek M (2003) Tetrahedron 59 1283-1288, with permission.)... 

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