House and Senate Republican leaders have reached an agreement in principle that would lower the corporate tax rate to 21 percent beginning in 2018, several people briefed on the plan said, a central component of the $1.5 trillion tax plan they hope to vote into law by next week.

The agreement would also lower the top tax rate for families and individuals from 39.6 percent to at least 37 percent, a change that would deliver a major tax cut for upper-income households. . . . Democrats mounted a last-ditch effort to pressure the GOP to delay votes on the bill, arguing they should wait for Democrat Doug Jones — who defeated Republican candidate Roy Moore on Tuesday in an Alabama special election for a U.S. Senate seat — to join the chamber.

But Republicans rebuffed those attempts and are hoping to pass a final bill early next week.