Guatemala, basically the first example of the US flexing its new status as the global seat of capital, used this as one of its traps: place embargos on it, including weapons, in response to Arbenz doing SocDem things. Then Arbenz traded with the Soviets as they were the only major country to offer. The US used this as a major pretext for its campaign of painting Guatemala as a potential forward base for the Soviets and getting taken over by the reds. This campaign was part of its larger coup effort that included the use of US-trained death squads, genocide of the Mayan communities, and finally a bombing campaign to seal the deal. Lumumba had a similar experience, etc etc.

Obviously there are no countries that have no other interactions with the US prior to getting sanctioned. Every country is a potential target, friend or foe, and friends get turned into foes at the drop of a hat. A country gets sanctioned because it's already a target, the US already has some stated pretext and a few schemes it's implementing.