Compare DateTime Lists, c# linq -

i have list in c#

list<dates>  public class dates {     public datetime start {get; set;}     public datetime end {get; set;} }

in list:

start - end

how check if starttocheck between start, same endtocheck end list?

for example:

starttocheck = 2014-03-17 11:00:00 endtocheck = 2014-03-17 12:00:00

obviously, starttocheck in list nr2, not find it.

i tried

if (start <= starttocheck && end >= endtocheck)

but not working... help, please?

thanks

if want detect overlaps:

yourlist.where(x=> x.start <= endtocheck && x.end >= starttocheck)

And