Preparation of N-methylformamide 

Preparation of N-Methyl Amides (abbreviated)
D'Alelio and Reid, J. Am. Chem. Soc. 59, 109(1937)

The most generally useful method was to drop acid chloride very slowly, with
constant stirring, into three moles of amine in concentrated aqueous solution.
The temperature was kept at -20 to -10 oC during the addition. The methyl amides
were caused to separate by the addition of solid caustic potash to the mixture.
The separated amide was dried over caustic potash and distilled. Yields run from
85 to 95%. Similar yields were obtained when the amine was passed into a soln of
the acid chloride in dry toluene at -10oC followed by the addition of 20% sodium
hydroxide solution. For comparison various other methods of preparing amides
were tried. The reaction of dry methylamine on esters proved to be very slow but
with an excess of the aqueous amine, 68% of the heptamine was obtained after
several days. From the sodium salt of an acid and methylamine hydrochloride, a
good yield was obtained but it was difficult to purify. Acetamide and its sodium
salt were methylated, yields 50-60%. The methyl amides of formic and acetic were
obtained by passing the amine through the heated acids.

N-Methylformamide
J Cappon et al., Rec. Trav. Chim. Pays-Bas 113, 318(1994)

Sodium metal (1.38 g, 60 mmol) was dissolved in 100 mL of anhydrous methanol
under gentle reflux. To this solution of sodium methoxide, first 3.7 mL (60
mmol) of methyl formate was added and then 4.00 g (59 mmol) of methylammonium
chloride under cooling with and ice bath. The solution was stirred overnight at
room temperature. The suspension was filtered over celite and the filtrate was
carefully concentrated in vacuo (30oC, 20 mmHg). The residue was taken up in
dichloromethane and the precipitated salts were removed by filtration. The
filtrate was dried on HgSO4, filtered again and the solvent was carefully
evaporated in vacuo. This resulted in 3.49 g of N-methylformamide (99% yield).
