2023_BG_5A_1 - Thiourea formation on 2-amino-5-nitropyridine

[KlementineJBS]

Reaction scheme

Outcome

2.083 g (6.89 mmol), 96%

[KlementineJBS]

1. Dissolved KSCN (866 mg, 8.63 mmol, 1.2 equiv.) in acetone (50 mL)
2. Added benzoyl chloride (0.9 mL, 7.9 mmol, 1.1 equiv.)
3. Heated to 60 C and stirred for 20 minutes
4. Added 2-amino-5-nitropyridine (1.00 g, 7.19 mmol)
5. Stirred at 60 C for 30 minutes.

TLC indicated reaction not yet complete.

2o% ethyl acetate in hexanes, ninhydrin

6. Left to heat and stir for a further 30 minutes

TLC indicated still not complete - a new spot appeared. Worked up anyway.

7. Poured over ~150 mL ice water
8. Vacuum filtered and washed with cold water (2 x 15 mL) and cold isopropanol (2 x 15 mL) to yield ~ 200 mg of a dark yellow-green solid. Filtrate was bright yellow in colour.

Empty vial: 15.9082 Full vial (filter cake): 16.1128 Mass: 0.2046 g

10. Extracted filtrate with ethyl acetate (2 x 100 mL, 1 x 50 mL), washed with brine and dried over MgSO4
11. Rotovapped down to give a fine yellow-orange powder

Empty vial: 15.9761 Full vial (extraction): 17.8545 Mass: 1.8784 g

[KlementineJBS]

LRMS

Filter: 301.02 [M-H]-, 625.13 Extract: 301.07 [M-H]-, 625.11

2023_BG_5A_1 filter.pdf 2023_BG_5A_1 extract.pdf

2023_BG_5A_1 extract.d.zip

[KlementineJBS]

H NMR

NMR spectra from the two samples don't seem to match exactly but this may be due to concentration - the extracted sample seems much more concentrated. Uncertain about the integrals - one or both samples may be contaminated.

2023_BG_5A_1.pdf

2023_BG_5A_extract_1.zip 2023_BG_5A_1 filter_1.zip

[KlementineJBS]

Recrystallisation solvent screen

Antisolvent	water	MeOH	EtOH	IPOH	tBuOH	THF	EtOAc	MeCN	toluene	dioxane	hexane
-	ins.	sol. with heat	sparingly sol. with heat	sparingly sol. with heat	sol. with heat	sol.	sol. with heat	sol. with heat	sol. with heat	sol. with heat	ins.

| water | - | - | - | - | crystals |