REAL ESTATE

January appears to be a big month for consummating deals. Among the bigger ones announced recently: Irvine developer O’Donnell, Armstrong & Partners bought 131 acres in Rancho Cucamonga for $15 million with the Boston Co., a Massachusetts pension fund adviser, and plans to build 2.5 million square feet of factories and warehouses. Construction on the land--next to a similar O’Donnell project--begins in the spring.

Erin Mason Ltd. Inc. of Newport Beach bought 300 acres in Riverside and San Bernardino counties from Ahmanson Commercial Development Corp. of Los Angeles for $18.5 million. Erin Mason said it would build roads and other amenities and sell lots to heavy industry.

Patrick F. Cadigan of Newport Beach bought Monterey Pines Apartments in Tustin for $13.7 million from Balcor Realty Co. of Skokie, Ill. Located on Williams Street, the complex has 224 units.

And the Coopers & Lybrand accounting firm signed a $7.9-million lease for 28,000 square feet of office space at 4675 MacArthur Court in Newport Beach, an Irvine Co. building. Coldwell Banker represented the landlord.