An Alexandria law firm, Brincefield, Middlton, Reiner & Tremaine, has purchased the boarded-up former Second Presbyterian Church at the northwest corner of Prince and St. Asaph streets in Old Town for $350,000. Parnter James (Bo) Brincefield said the firm is seeking permission from the Alexandria architectural board of review to preserve the 90-year-old Greek revival stone building and convert it to 12,000 square feet of office space in the Romanesque tradition. Michael & Michael is the architectural firm and William T. Bateman Inc. The contractor. The project isexpected to cost more than $900,000. Even the belfry is scheduled to be converted to office use.

James J. Aylor, who sold 163 new houses build in this area last year by U.S. Home Corp., has been honored as the area's outstanding seller of new single houses by the area-wide marketing council of builder organizations. Aylor, who now lives in a Montgomery Village town house, plans to move his family into a U.S. Home dwelling in Rock Creek Hills in June. He is the son of the late John Aylor, a builder who was instrumental in staging the home shows held at the D.C. Armory in the 1950s and 1960s.

Joel and Sara Lee Schnur recently wrote a glowing leter of thanks to Fairfax County builder Robert Batal, who constructed their house in the Lincolnwood section of Burke Center. The Schnurs enclosed a check for $24 for furnace repairs made by a repairman whom builder Bastal personally drove to the house in four-wheel-drive vehicle when a heat pump malfunctioned and the Schnur house was without heat during the heavy snows of February. "It was really above and beyond the call of duty since the house was no longer on warrantly and thus no longer your responsibility," wrote the Schnurs, who also commended Batal for building "sound houses and standing behind them."

The 107-acre John O'Hara at brickyard and Falls roads in Potomac has been sold to a limited partnership that includes Standard Investment Corp., a subsidiary of Standard Federal S&L. Forty-five two-acre lots with sewer and water service will be developed and sold to individuals and builders. Prices: from $90,000 to $120,000. The site adjoins Potomac Falls, where W.C. & A.N. Miller has been developing prestigious large-lot houses for a decade.

SHORTLY-Maryland broker John Y. Harrison, who recently opened his fourth and fifth branch offices in Silver Spring and New Carrollton, participates dramatically in his firm's week-long training programs for new agents. "You must be able to expaln and arrange financing to sell houses," he emphasizes. . . .For the second time in five months the voters in Santa Cruz., Calif., north of San Francisco, have rejected rent controls, which have become an issue in California since the passage of Proposition 13 (lowering realty taxes for property owners) last September. . . .Builder Jean Melkin has completed and sold a $700,000 house in Potomac. The four-bedroom house has 6 fireplaces, 11 bath and powder rooms and a dance floor in the recreation room. . . .Wilgus & Associates is developing 75 lots with 40-foot to 50-foot frontage in a previously undeveloped area of Bethany Beach, Del. The 33-acre property, just north of Sea Colony, has water and sewer services. Lot prices will be in the $20,000 range. . . .Former Washington architect peter Hasselman, whose educational building and construction sketches appeared in this section several years ago, now is affiliated with the Whisler-Patri architectural firm in San Francisco and he is doing some illustrated articles for the Chronicle-Examiner there. . . .Cohen and Haft, Holtz, Kerxton & Associates of Silver Spring devised a cluster arrangement of houses for Poretsky-Starr's award-winning New England Woods subdivision in Burke Centre. Result: trees were saved and most of the houses are on private non-through roads.