Gramine, 3-(dimethylaminomethyl)indole,
R-CH2-N-(CH3)2, can be made in this extremly easy fashion:

All the following are cooled in an ice bath.
12.33g 53%(aq)dimethylamine, 20ml glacial acetic acid, and 11g 37%formaldehyde. To this is 16.8g indole added. An exothermic reaction results as the indole dissolves. After several hours the solution is made alkaline with (aq)NaOH. The mass crystallizes and is suction filtred, washed and dried. Approximately 25g gramine is obtained.

Fucking hey! Thatīs a pretty good yield(God I wish other things were produced in this easy and high-yielding way)

Now if someone for some naughty reason would like to have that alkyl chain one carbon longer. R-CH2-CH2-N-(R')2. Could it be so freaking simple as to just use acetaldehyde instead of formaldehyde? Of course not. But why? Thatīs finally the question.

Strontium

indole-CH(CH3)-N(CH3)2

but you want this:

indole-CH2-CH2-N(CH3)2

This is gramine:

indole-CH2-N(CH3)2

The gramine can be methylated with CH3I and reacted with cyanide to produce this substance:

indole-CH2-CN,

which can be reduced to produce tryptamine or saponified to produce IAA.

The dimethylamine condenses with the formaldehyde to form the electron deficient species Me2N=CH2, which in turn adds to the nuceleophilic indole 3-position.

As you can see, there is no 2-carbon equivalent to the iminium ion above, as the mechanism is dependent on the methylene group being attached directly to the dimethylamine.

Gramine can also be converted to something funny. Gramine + nitropropane --> 3-(alpha, alpha-dimethyl-alphanitroethyl)indole.
R-CH2-N-(CH3)2 + CH3-CH2-CH2-NO2-->
R-CH2-C(CH3)(NO2)-CH3.
This 3-alpha, alpha-blah can be reduced to alpha-methyltryptamine. Not too funny but what the hell.

Strontium