Answer:
December 31, 2018, bonds are issued
Dr Cash 461,795
Cr Bonds payable 450,000
Cr Premium on bonds payable 11,795
amortization expense per coupon = $11,795 / 6 coupon payments = $1,965.83
June 30, 2019, first coupon payment
Dr interest expense 18,284.17
Dr Premium on bonds payable 1,965.83
Cr Cash 20,250
The amortization of the premium on bonds payable decreases the interest expense.