Net Framework 45 Developer Pack Link -

.NET Framework 4.5 Developer Pack (which includes the Multi-Targeting Pack) is no longer available as a standalone direct download from official Microsoft pages because version 4.5 reached its end of support on January 12, 2016

Microsoft provides separate downloads for the base version and its sub-versions (4.5.1 and 4.5.2): net framework 45 developer pack link

Once finished, you will see: Click “Finish.” net framework 45 developer pack link

https://dotnet.microsoft.com/en-us/download/dotnet-framework/net45 net framework 45 developer pack link