hydrogenchloride; hypophosphorous ether; sodium nitrite 1.) 0 deg C, 0.5 h, 2.) RT, overnight; Yield given. Multistep reaction. Yields of byproduct given;

With  hypophosphorous ether; acetic acid; sodium nitrite  1.) acetone, 0 deg C, 0.5 h, 2.) acetone, RT, overnight;  Yield given. Multistep reaction;