Synthesis
The general procedure for the synthesis of 4-hydrazino-2-methylthiopyrimidine from 2-methylthio-4-chloropyrimidine is as follows:
Step 1: Preparation of N-(2-methylthiopyrimidin-4-yl)hydrazine
In a 250 mL round bottom flask, 4-chloro-2-methylthiopyrimidine (5 g, 31.1 mmol), hydrazine hydrate (4.5 g, 140 mmol) and potassium carbonate (6.45 g, 46.7 mmol) were dissolved in ethanol (50 mL). The reaction mixture was heated to reflux for 3 h. After the reaction was completed, it was filtered while hot. The filter cake was washed with ethanol (30 mL). The filtrate and washings were combined and concentrated under reduced pressure to remove the solvent to give the crude product. Purification of the crude product by ISCO fast column chromatography (eluent: 30% to 100% hexane solution of ethyl acetate) afforded N-(2-methylthiopyrimidin-4-yl)hydrazine as a white solid (2.8 g, 57.6% yield).
References
[1] Bioorganic and Medicinal Chemistry Letters, 2013, vol. 23, # 5, p. 1486 - 1492
[2] Patent: US2011/34470, 2011, A1. Location in patent: Page/Page column 40
[3] Patent: US2005/261354, 2005, A1. Location in patent: Page/Page column 77
[4] Bioorganic and Medicinal Chemistry Letters, 2013, vol. 23, # 12, p. 3565 - 3569
