Photochemical and Thermal Bergman Cyclization of a Pyrimidine Enediynol and Enediynone

• DOI: 10.1021/ol006061j
• Publication Date: 2002-07-26T06:06:54Z
• Authors: Nakyen Choy; Beatriz Blanco; Jenghai Wen; Awtar Krishan; K. C. Russell
• Keywords: Pyrimidines; Cyclization; DNA, Superhelical; Photochemistry; Antineoplastic Agents; Enediynes; 01 natural sciences; 0104 chemical sciences

[reaction: see text] Novel 10-membered pyrimidine enediynes (3 and 4) were synthesized in seven and eight steps, respectively. These compounds were compared for their abilities to undergo Bergman cyclization both thermally and photochemically. Alcohol 3 readily cyclized both thermally and photochemically in (i)PrOH, while ketone 4 only showed efficient thermal cyclization. Both compounds were also shown to cleave dsDNA under the appropriate conditions.