Russian Debt Payments Rescheduled: Russia agreed to pay Western commercial banks $500 million in back interest by April and got another three-month extension on payment of its $26-billion principal. The agreement ended two days of talks between a Russian delegation led by Deputy Finance Minister Andrei P. Vavilov and representatives of about 600 creditors, led by Deutsche Bank of Germany. Under the accord, Russia will pay the banks $100 million by year's end and another $400 million by April. The money will be held in trust until the debt-restructuring agreement is finalized. The $500 million to be paid by April reflects back interest owed by Russia for 1992 and '93.