Cyclic acetals with aldehydes

Budesonide, sold under the brand name Pulmicort, among others, is a steroid medication. It is available as an inhaler, nebulization solution, pill, nasal spray, and rectal foam. The inhaled form is used in the long-term management of asthma and chronic obstructive pulmonary disease (COPD). The nasal spray is used for allergic rhinitis and nasal polyps. Modified-release pills or capsules and rectal forms may be used for inflammatory bowel disease including Crohn's disease, ulcerative colitis, and microscopic colitis.

Levoglucosan (C6H10O5) is an organic compound with a six-carbon ring structure formed from the pyrolysis of carbohydrates, such as starch and cellulose. As a result, levoglucosan is often used as a chemical tracer for biomass burning in atmospheric chemistry studies, particularly with respect to airborne particulate matter. Along with other tracers such as potassium, oxalate, and gaseous acetonitrile, levoglucosan has been shown to be highly correlated with regional fires. This is because the gas emitted by the pyrolysis of wood (biomass) contains significant amounts of levoglucosan.

Proligestone, sold under the brand names Covinan and Delvosteron, is a progestin medication which is used in veterinary medicine.