The word "Sell" is not a common expression in diplomacy. Although there is a huge rivalry in military developments, It is a fact that Russia has lots of economical interest in west. That causes some unreliability in Russian diplomacy regards to her allies.
Diplomacy is not a 0 & 1 game. There are lots of condition between 2 extremes. Iran should take the advantages of having relation with every country. If we have some limited relation with USA, It was possible to put some pressure against some unfriendly diplomacy from Russia. ٰ
Putin is only responsible for the nation of Russia, not more. It is childish to think Putin will scarify Russia's future for others. Nobody fall in love in diplomatic relationship. This is not the case only for Russia but true for every country who is not suffering from ill diplomacy policy.