Walgreen ( WAG) said it may take its bid to acquire Longs Drug Stores ( LDG)directly to Longs shareholders if the pharmacy chain refuses to discuss a deal. In a letter sent to the board of Longs on Monday, Walgreen disputed Longs' position that it's not willing to accept the regulatory risks in connection with an acquisition. Walgreen also said Longs should have no concern with its ability to finance the proposed transaction. "Our proposal is compelling -- it would deliver superior value to Longs stockholders relative to the CVS transaction and can be consummated without undue delay," said the letter from Jeffrey Rein, Walgreen chairman and CEO. In August, Longs agreed to sell itself to CVS Caremark ( CVS) for about $2.9 billion, or $71.50 a share. The offer carried a sizable premium, but because Longs controls a valuable real estate portfolio -- and hasn't gotten the portfolio appraised -- its shareholders felt shortchanged. As a result, CVS managed to secure just 4.5% of Longs' stock by the time its first tender offer expired. Earlier this month, Walgreen offered to buy Longs for $75 a share, and also agreed to cover a breakup fee, equal to another $3 a share, if Longs would accept its proposal. But Longs has rebuffed the offer from Walgreen.