Ketamine was first developed in 1962. It is on the World Health Organization's List of Essential Medicines, the most important medication needed in a basic health system. It is legally sold under a very wide variety of brand names, including Ketalar.
If the crime you commit (generally just first degree murder) is in a state that does not have the death penalty then the only way you can be executed is if you are tried in a federal court as opposed to a state court.
Texas, for example, imposes death sentences on all those convicted of capital murder, its highest level murder charge. In California, on the other hand, aggravated first degree murder can draw either the death penalty or life in prison without parole.