I want alert when a five or more than five transaction gets failed within 1 minute interval.
I captured failed transaction in Business Transaction. Incident is configured using violation count measure on this BT.
But I am not getting expected result, as Business Transaction shows 7 count within 1 minute interval and still there is no incident generated in dynatrace.
There's a number of ways to get this behavior and you seem to be using a mix of them that is a bit confusing and complex. First, note that those PurePaths being captured by the BT are not actually being marked as failed the yellow is just a warning that they have some exceptions marked as non-critical. Also, the violations count measure is basing the number of violations of the thresholds defined in the measure you selected and since you haven't noted the thresholds there I would assume this hasn't been considered.
What I would do is since you seem to already have a BT working that is capturing those PurePaths in your screenshot, define the incident around the PurePath response time measure associated with that defined business transaction with the aggregation 'count' and the threshold set as 5 (note that the numbers in the threshold config will be displaying as ms but if you set the aggregation as count it will be for the count of PurePaths captured so the ms isn't really appropriate). Then as long as the timeframe is set to one minute should get get an incident when 5 or more PurePaths are captured by that BT.
Lastly, if you ever have trouble getting an incident to trigger you should chart out the measure the incident is based on with the same aggregation and a high resolution so you can see if the measure as defined is violating the threshold as you expect (or if it is being created at all).