bond purchase includes interest

The accrued interest you paid is not deductible. Rather you subtract it from your next coupon/interest payment. So you receive $600 every six months and paid $500 accrued interest, then your next interest payment will be reported as $100 (or rather as $600 and -$500 on the next line in Schedule B). Also, the person who received the interest will report the accrued interest as income on their Schedule B.

Also, I think if you bought near the end of the year and the coupon payment was received the following year, you only subtract the accrued interest on your next year's tax return. But the person who receives the accrued interest will report it on this years tax return.