Synthesis of β-diketone compounds for UV-A ultraviolet absorbent

Two UV-A ultraviolet absorbents:1-(4-methoxy-phenyl)-3-phenylpropane-1,3-dione and 1-(4-tert-butylphenyl)-3-(4-methoxyphenyl) propane-1,3-dione were synthesized from aromatic ketone and ester by classical Claisen condensation using NaNH_2 as strong alkali.Their compositions and structures were characterized by means of elemental analysis,UV,IR and(()~1HNMR).The results showed that two aromatic β-diketone compounds existed in the enol form in chloroform,and they were kinds of good UV-A ultraviolet absorbents in UV region from 320 to 400 nm.