BANK OF BOSTON <BKB> SEES IMPROVED 1ST QUARTER Bank of Boston Corp expects first quarter earnings will range between 90 cts and one dlr a share, up from 79 cts a share last year, Chairman William Brown said. He told shareholders the company has a 190 mln dlr exposure in loans to Brazil if that country defaults on its debt payments. If a default does occur, it would first quarter earnings by about five cts a share, which would bring the bank's in the lower level of the estimated range, he added. Brown noted the 1986 first quarter net included a 17 cts gain from loan restructurings which will not appear this year. Brown said the bank's other nonperforming assets, not including its Brazilian exposure, could rise to over 700 mln dlrs at the end of this quarter compared with 669 mln dlrs a year earlier and 614 mln dlrs at the end of 1986. He said the increase includes all of its Equadorian loans which he expects will be ultimately repaid after the company recovers from an earthquake earlier this year. Brown said the increase also includes some Mexican and Venezuelan loans as those nations are also facing credit problems. Brown said the Bank of Boston remains "cautiously optimitic about the full year even if our Brazilian exposure were to be on nonaccural all year." In 1986, the bank earned 3.69 dlrs a share, or 232.8 mln dlrs on net interest revenues of 1.08 billion dlrs. President Ira Stepanian told the shareholders's meeting the bank's total loans to Argentina, Brazil and Mexico totaled 875 mln dlrs at the end of 1986, 37 pct of its primary capital. Brazil loans total 300 mln dlrs, of which about two-thirds are affected by its suspension of interest payments on its medium and long term foreign debt.