[ferda]

I'm trying to attach a primary amine to 6-chlorouracil, specifically, the carbon bearing the chlorine (refer to image).  The problem is getting this reaction to work! All of the obtained H/C NMR spectra indicate starting materials only. So far I've tried:
1) switching the solvent and base from EtOH & NEt₃ to DMSO/Na₂CO₃ and cranking the heat up,
2) heating the reaction using a microwave (as opposed to a sealed reaction vessel),
3) tweaking with the reaction time & temperature,
4) adjusting/changing the column conditions (initially 20:1 DCM:MeOH) by gradually increasing the MeOH proportions,
and 5) using a commercially available Bn-NH2 as the amine source (to rule out if I was working with a bad batch of 6-chlorouracil).
I have done the reaction a total of ten or eleven times, changing one variable each time to try and rule out factors that might be interfering with the reaction. I've been using a procedure that I found in the literature so I know the reaction can be done (pasted below).

The original procedure that I followed is as follows: "A mixture of chlorouracil (3) (218 mg, 1.49 mmol), ribitylamine (10) (413 mg, 1.79 mmol), NEt3 (0.41 mL, 2.98 mmol) and EtOH (3 mL) was heated in a closed and sealed reaction vial at 150 °C for 1.5 h. After cooling to ambient temperature the mixture was concentrated in vacuum and the residue purified by column chromatography (SiO2, MeOH/CH2Cl2 1:20, Rf 0.06) to give title compound (11) (350 mg, 1.03 mmol, 69%) as a colorless solid."
Image & procedure obtained from "Bender, M.; Mouritsen, H.; Christoffers, J. Beilstein J. Org. Chem. 2016, 12, 912–917. doi:10.3762/bjoc.12.89"

[wildfyr]

Have you looked at Buchwald Hartwig type amination conditions? AKA, throw some Pd in there. It literally might work just to try whatever Pd(II) salts you might have in lab. Give them a decent kick with heat though, 80-100C.

This reaction's conditions range from "really picky" to "works like a charm"

[wildfyr]

It's a recent paper, you could also reach out to the authors.