Northamptonshire's total left the home side needing a daunting 368 to avoid the possibility of the follow-on. They were 122 for 2 at the close.
Nottinghamshire's wicketkeeper, Wayne Noon, claimed a club record of seven catches in an innings on the opening day against Kent at Trent Bridge. He provided support for Nottinghamshire's four-pronged seam attack as Kent subsided from 93 for 1 to 191 all out.
Tim Phillips and Andrew McGarry marked their first-class debuts with promising performances when Essex met Sri Lanka A at Chelmsford.
They collected six wickets between them as the tourists were bowled out in the final over of the day for 364. Phillips, an 18-year-old left-arm spinner, finished with figures of 4 for 42 from 17 overs, while McGarry, a 17-year-old fast bowler, picked up 2 for 72 from 20 overs.