When selecting exercises for your programme you should build from more general movements to more sport specific exercises. Alternate-side pull-ups are an example of a more Muay Thai clinch specific version of the general pull-up exercise.
Hang with your arms at full extension
Draw your elbow into the side of the body
Raise chin to the bar
Once you can do more than 5 regular pull-ups, this exercise allows you to build strength by loading with enough intensity to bring your maximum repetition total down to 5 or less per side — by progressively using less assistance from the second arm and/or using a wider grip width.