Malonic anhydride
Malonic anhydride or oxetane-2,4-dione is an organic compound with chemical formula C3H2O3 or CH2(CO)2O. It can be viewed as the anhydride of malonic acid, or a double ketone of oxetane.
Malonic anhydride was first synthesized in 1988 by ozonolysis of diketene. Some derivatives, such as 3,3-dimethyl-oxetane-2,4-dione, are known.