Kethoxal

Formula : C6-H12-O4
CAS : 27762-78-3 

Modifies guanine containing oligoribonucleotides by reacting selectively with guanine in polynucleotides.

Keto-anhydrokinamycin

Formula : C18-H10-N2-O6
CAS : 120796-25-0 

Isolated from Streptomyces murayamaensis; keto-epoxide kinamycin intermediate.