Tottenham manager Andre Villas-Boas, speaking after a UEFA-hosted meeting of elite coaches, said they were "unhappy" and wanted more settled preparation for their teams each season.
"We have alerted UEFA that something has to be done," Villas-Boas said after the annual two-day session attended by 16 coaches, including Carlo Ancelotti of Real Madrid.
Tottenham's record 100 million euro ($132 million) sale of Gareth Bale to Madrid was among the big transfers sealed near Monday's deadline.
Napoli coach Rafa Benitez said the "beginning of August" or Aug. 15 were suggested as better deadlines than this season's Sept. 2 transfer window closure, which came after European leagues began.
The call follows UEFA President Michel Platini saying that "this window is too long and will have to shorten it."
"We will ask FIFA to have a look into what we propose and for all European leagues to start at the same time," Platini said after last week's Champions League draw.
Securing a place in that lucrative competition is seen as a key factor for clubs wanting to prolong their trading options.
Villas-Boas identified that "the problem is the discrepancy" between coaches seeking stability and some clubs who seek to ensure Champions League qualification.
A place in the 32-team group stage is typically worth at least 15 million euros ($19.7 million) in prize money from UEFA.
Villas-Boas said Schalke coach Jens Keller pointed out that the German club could buy midfielder Kevin-Prince Boateng from AC Milan only after winning its Champions League playoff last week.
"Boateng is one example and it's quite dangerous," Benitez said. "You prepare everything with your players and, one week after, the players could be playing against you."
Napoli, like Tottenham, sold its star player in the off-season, getting 64 million euros ($85 million) from Paris Saint-Germain for Uruguay forward Edinson Cavani.
Both Napoli, which is in the Champions League, and Tottenham, a Europa League contender, reinvested in signing several high-class players while conforming to UEFA's "Financial Fair Play" rules which require clubs to aim toward breaking even.
"When a player of that stature leaves, you have to look at it from a very positive vantage point," said Benitez, whose new recruits include forward Gonzalo Higuain and defender Raul Albiol from Reral Madrid. "So long as the club is better off afterwards, I think it's a good thing."
Completing the Bale deal stretched throughout August while Tottenham positioned itself to sign midfielders Erik Lamela from Roma and Christian Ericksen from Ajax last Thursday.
"The influence of Real Madrid has been very, very strong," Villas-Boas said in Spanish. "You get to a point where you have to consider if it's feasible . in not accepting the offer . whether you can press on with the player (Bale) in that state of mind."
In other issues, the coaches discussed whether the away-goal rule — which some argue now promotes negative tactics — should no longer apply in knockout matches.
"It should be maintained," Villas-Boas said. "It was raised that also (in) extra time, the away goals shouldn't count."
The Tottenham coach said the session supported UEFA's decision to enter the Europa League winner in the Champions League from 2015.
Although the coaches discussed FIFA's international match calendar, Benitez said switching the 2022 World Cup in Qatar from a June-July slot was not raised.