It says "and if this too is unavailable,it can be synthezized easily by the Eschweiler-Clarke methylation(15)of the very basic building block 1-amino-2-propanol,using formaldehyde and formic acid.I'ev spent a lot of time looking for this step,but can't find it.I know it's there and that I probably looking for it with the wrong wording.Can someone point me in the proper direction? Thank You

A search for "Eschweiler" gave 25 hits, among others the following, using either formaldehyde or paraformaldehyde:

Post 401843

(Antoncho: "The easiest PhCOOH -> PhCHO reduction yet!", Novel Discourse)

Post 290447

(Z_Hound: "Methylation: Eschweiler-Clark", Tryptamine Chemistry)