Reductive methylation

[PolytheneSam]

There's been a contraversy for a while on whether or not tryptamines can be methylated with formaldehyde and sodium cyanoborohydride or other reducing agent.  I found these patents on this type of reaction.  Most use sodium cyanoborohydride.

Patent US5037845

column 8 line 54+

Patent US5298520

col. 23 l. 24+, col. 24 l. 57+

Patent US5317103

example 3 col. 20 NaBH4, ex. 37 col. 30

Patent US5852049

ex. 40 col. 31-32

Patent WO02079153

examples 27 and 32 formic acid

Patent US5300645

Pictet-Spengler