Preparation
To a flask equipped as in Preparation 2-6 is added 162.0 gm (1.0 mole) of ethyl orthoacetate, 42.0 gm (1.0 mole) of cyanamide, and 134.0 gm (2.0 moles) of acetic anhydride. The reaction mixture is heated to 130-140°C and the ethyl acetate and acetic acid are distilled over. The heat is removed until the initial vigorous reaction subsides and then the heating is continued at 135-140°C until most of the remaining ethyl acetate and acetid acid have distilled over (approx. 1 hr). The residue is then distilled under reduced pressure to afford 100.8 gm (90%), b.p. 90-95°C (20 mm Hg).
Synthesis
General methodology: The compound was synthesized with reference to literature methods. The standard procedure we used is detailed below: the mixed system of the original triethyl acetate (0.12 mol), cyanamide (0.1 mol) and a small amount of acetic acid (a few drops) was refluxed for 6 hours, followed by distillation and purification under reduced pressure (14 mmHg).
References
[1] Phosphorus, Sulfur and Silicon and the Related Elements, 2016, vol. 191, # 5, p. 759 - 764
[2] Patent: US5750545, 1998, A
[3] Patent: WO2008/42928, 2008, A2. Location in patent: Page/Page column 33
[4] Journal of Organic Chemistry, 1963, vol. 28, p. 1816 - 1821
