1-(3-Ethynylphenyl)-3,3-dimethyl-2-azetanone3,3-Dimethyl-1-(3-ethynylphenyl)azetan-2-one3-(3,3-Dimethyl-2-oxoazetidin-1-yl)phenylacetylene3,3-Dimethyl-1-(3-ethynylphenyl)-2-oxoazetane3,3-Dimethyl-1-(3-ethynylphenyl)azetidin-2-one3,3-Dimethyl-1-(3-ethynylphenyl)-2-oxoazetidine