Here's a sentence I made up:
"He seemed to had not understood what I had said to him"
Is this sentence correct? I tried searching for similar sentences by putting quotation marks around 'seemed to had not', and out popped roughly 5-6 results, but that doesn't seem to be that many, especially because some of those could've been mistakes, and I couldn't find any questions like this.
Also, assuming it is correct, if I change the position of 'not', like so:
"He seemed to not had understood what I had said to him"
Would it still be grammatical?