1. It undergoes rapid polymerization, including forming a hemiacetal cyclic dimer. 2. These do not form as readily as hemiacetals and acetals. 3. The conversion of a hemiacetal to an acetal is an S N 1 reaction. 4. "' Cloxotestosterone acetate "'( chloro hemiacetal ether of testosterone. 5. Hemiacetals and hemiketals are generally unstable compounds.6. Acetals are stable compared to hemiacetals but their formation is a reversible equilibrium as with esters. 7. The aminal and the hemiaminal groups are analogous to hemiacetals and acetals with nitrogen replaced by oxygen. 8. Glucose and many other aldoses exist as cyclic hemiacetals whereas fructose and similar ketoses exist as cyclic hemiketals. 9. Aldehydes such as formaldehyde for example, are hydrated by water ( they form hemiacetals and acetals ). 10. "' Cloxotestosterone "'( chloro hemiacetal ether of testosterone which was never marketed.
