Top Democrats on Beacon Hill appeared set to end their final formal meetings of the Legislature’s two-year session without deals on major proposals that had shaped conversations for months, including on economic development and hospital oversight.

Formal lawmaking was scheduled to end by Thursday, but lawmakers readily ignored the clocks and continued marathon sessions overnight in a last-ditch effort to produce accords before Democratic leaders ceded their ability to muscle through proposals over objections.

Apparent communication breakdowns and finger-pointing between the House and Senate left several high-profile matters unresolved, as legislators prepared to cap off more than 20 straight hours of lawmaking.

Rep. Aaron Michlewitz, a North End Democrat, said negotiators in the House kept talking to counterparts in the Senate “the entire way” on bills that the other branch was willing to engage on.

“Some of them there was just no engagement. We kept trying and trying and trying and just ran against brick walls and eventually, we had to stop running into the brick wall. So here we are,” he told reporters just before 7 a.m. Thursday.

Senate President Karen Spilka said assigning blame “gets us nowhere.”

“I believe that these are complex bills. They take a lot of time and energy, and I’m proud of the Senate of rolling up their sleeves and working hard,” she said after 7:30 a.m.

Some cracks started to show after midnight when talks between key House and Senate lawmakers appeared to fall through on a highly anticipated clean energy bill.

Both Democratic negotiators publicly declared the proposal was all but dead in the water and a deal was unlikely to surface Thursday morning.

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Sen. Michael Barrett, a Lexington Democrat who led talks on behalf of the Senate, said he had been looking forward to a “glorious morning after midnight.”

“I’m not sure we’re going to have quite the celebration that I had been planning,” he told reporters. “I’m not sure the House subscribes to the idea that we should give people relief, even as we expand the grid and make people pay a significant amount to do so.”

Rep. Jeff Roy, a Franklin Democrat who led talks in the House, accused the Senate of “going back on its word” by not advancing language around siting and permitting that he alleged had been agreed to before each branch had publicly released its bills earlier this year.

“Those components on siting and permitting are part of both of the bills,” he said as it neared 1 a.m. “There’s no reason why we can’t do it and they agreed to do siting and permitting, and they’re going back on their word.”

In the wake of the Steward Health Care bankruptcy, which left thousands at risk of losing access to local hospitals, legislators pledged to take action to prevent a similar situation from happening again.

But legislation aimed at the root causes of the Steward Health Care crisis was put on the back burner after talks became intertwined with a separate prescription drug pricing proposal and both the House and Senate became “frustrated,” Mariano said.

“I wanted to get away from the frustration that my staff was going through and the Senate staff was going through and we did that,” he said. “We will continue to work on these bills.”

A closely watched economic development bill also did not make it across the finish line Thursday, though top Democrats suggested they could address some portions of the proposal during the remainder of the year in informal sessions, when any one lawmaker can block advancing bills.

The House and Senate took different approaches to a multi-year investment initiative in the life sciences industry.

“The Senate, for the first time in about 20 years, stepped away from the commitment to MassBio, which is something that we wanted to know why, and we didn’t get any answers. We couldn’t get it to an agreement so consequently we didn’t do it,” Mariano said.

Spilka said she was not sure what Mariano was referring to.

“We continued in our proposals to support them at the highest level that was ever offered,” she said.

Other negotiating groups, known as conference committees, found better luck.

Six lawmakers tasked with hashing out a compromise on a massive borrowing bill — focused on addressing a housing affordability and availability crisis in Massachusetts — managed to reach a deal just before 6:30 a.m.

Sen. William Brownsberger, a Belmont Democrat who helped negotiate the legislation, said the final $5.1 billion version does not include an expansion of the Massachusetts Water Resources Authority, nor language requiring landlords to pay broker’s fees.

“It’s a great product,” he said.

Lawmakers also managed to put before Gov. Maura Healey legislation that updates state law to make it easier for LGBTQ families to become parents, including through adoption. That deal surfaced around 11 p.m. Wednesday and was one of the first proposals to clear negotiations.

A measure that expands the number of liquor licenses in Boston also appeared on track to make it to Healey but eventually stalled out, even after negotiators picked up the documents necessary to file an accord.

Brownsberger, who led talks on behalf of the Senate, said there were no issues with the bill but it was not expected to cross the finish line Thursday.

“There’s no issues. It’ll get done,” he said.

Democrats also signed off on a proposal around 3:30 a.m. that expands benefits for veterans but kept out of the final version a House-backed provision that would have allowed for slot machines on properties run by veterans groups.

Sen. John Velis, a Westfield Democrat, noted that the legislation included many provisions aimed at veterans’ behavioral health.

Velis said, “The behavioral health stuff is a big focus of mine because there’s been a dearth of behavioral health assistance for veterans for a long time now, and this is going to go a long way to being helpful.”