Drugstore chain Walgreens Boots Alliance WBA.O slumped 5.10% after the company kept its 2022 forecast for low-single digit earnings growth unchanged. By Chuck Mikolajczak NEW YORK, March 31 (Reuters) - U.S. stocks were poised to end the biggest quarterly decline in two years on a down note on Thursday as worries about the continuing conflict in Ukraine and its inflationary effect on prices and the Federal Reserve persisted. The United States imposed new Russia-related sanctions, and U.S. President Joe Biden announced the largest release ever from the country's emergency oil reserve.