TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (Claimed): Preparation of (I) comprises reacting (1,3)-dioxan-5-one compounds of formula (aa) with carbonyl compounds of formula XC(O)H (bb) or Y1C(O)H (cc). Preferred Composition: The preparation comprises at least one carrier suitable for at least one dermatological, cosmetic or pharmaceutical preparation or household products. The preparation contains at least one further organic functional material comprising host materials, matrix materials, electron-transporting materials, electron injection materials, hole transport materials, hole injection materials, electron blocking materials, hole-blocking materials, exciton blocking materials and/or emitter. ACTIVITY - Antipsoriatic; Antiseborrheic; Dermatological; Nootropic; Hepatotropic; Antiinflammatory; Antiarthritic; Antirheumatic; Analgesic; Vulnerary; Neuroprotective; Osteopathic; Cytostatic; Virucide.    MECHANISM OF ACTION - None given.    SPECIFIC COMPOUNDS - 25 Compounds (I) are disclosed e.g. (4Z,6Z)-2-ethoxy-4,6-bis((4-methoxyphenyl)methylene)-2-methyl-1,3-dioxan-5-one of formula (Ia), (4Z,6Z)-4,6-bis((3,4-dimethoxyphenyl)methylene)-2-ethoxy-2-methyl-1,3-dioxan-5-one, (4Z,6Z)-4,6-bis((2,4-dimethoxyphenyl)methylene)-2-ethoxy-2-methyl-1,3-dioxan-5-one, (4Z,6Z)-4,6-bis((2,4,5-trimethoxyphenyl)methylene)-2-ethoxy-2-methyl-1,3-dioxan-5-one and (4Z,6Z)-4,6-bis((3,4,5-trimethoxyphenyl)methylene)-2-ethoxy-2-methyl-1,3-dioxan-5-one.    EXAMPLE - Potassium hydroxide (34.89 mmole) was placed in ethanol (20 ml). Then 2-ethoxy-2-methyl-1,3-dioxan-5-one (15.61 mmole) dissolved in ethanol (10 ml) was added and then 4-methoxybenzaldehyde (34.89 mmole) was added dropwise within 30 minutes. Then the mixture was heated for 3 hours at reflux. The ethanol was distilled off and cooled to room temperature. Then water (50 ml) was added to precipitate a solid, which was washed with water (10 ml). The resulting solid was recrystallized in ethanol (85 ml) at the boiling point and dried to obtain (4Z,6Z)-2-ethoxy-4,6-bis((4-methoxyphenyl)methylene)-2-methyl-1,3-dioxan-5-one as yellow crystals.