if you didn't pay it you can't claim it.
if you have a real estate tax escrow account your monthly deposits and any money deposited into it at the closing of the purchase are not deductible. the IRS position is that the escrow agent is your rep and thus the taxes are not paid. disbursements from the escrow a/c to the tax authorities are deductible but if you just closed on the property you may have to reduce the disbursement by a credit you got on the closing statement for taxes there were due for the period you did not own the property.
