León Biriotti (1929-2020) was a Uruguayan composer, oboist and conductor. He studied with Enrique Casal Chapi, Alberto Ginastera and attended György Ligeti's Darmstadt lectures. He composed more than 111 works but few have made it to performance or record. His musical periods go from modernist avant-garde to postmodernism.
An incredible 2015 performance of his first opera "Rashomon" can be viewed here: https://www.youtube.com/watch?v=FSD3V891lGc
Three preludes from the opera "Ana Frank": https://youtu.be/2MBY1zMdxxw?t=216
Sinfonia da Requiem (1999):
Mov.1. https://youtu.be/77k57chTSYk
Mov.2. https://youtu.be/vYzsSrtJKTw
Mov.3. https://youtu.be/1iAcKzZHCvc