If i loose the single connection can i send my coins to an exchange wallet even if i'm not synced with the last blocks of the blockchain or i need to wait to get the connection again synched?
the transaction sending your coins should be included in the current (ie last) block, so you need to wait till the wallet is synced
you may find the nodes to add on the Cryptopia exchange site, currently they are
addnode=192.154.102.157:22460
addnode=188.40.131.43:22460
addnode=80.193.161.231:22460
addnode=139.99.168.237:22460
addnode=51.15.189.143:22460
addnode=193.70.36.168:22460
addnode=121.2.70.114:22460
addnode=115.125.216.214:22460
addnode=188.166.239.235:22460
addnode=146.71.77.70:22460
addnode=107.170.49.17:22460
addnode=51.254.36.84:22460
addnode=51.255.157.116:22460
addnode=37.48.86.167:22460
addnode=46.4.113.143:22460
addnode=178.151.171.12:22460