[donozark]

Although much improved, the S300 was deployed in 1979 under the old Soviet Union. It would appear for now anyway, the S400s stay in Russia proper and Kaliningrad.

[Navy Patriot]

S400 is primarily deployed inside Russian borders around major cities, however several sources claim a small number are deployed in Syria, two at Khmeimim air base in Latakia province, and another two at Tartus naval port, both Russian installations.

It is unlikely there are more as the purpose is to protect Russians.

That means Southern Syria is at long range for the 400s.