Condensation of 4-isothiocyanotopyridine [76105-84-5] (1) and 3,3-dimethyl-2-butanamine [3850-30-4] (2) gives thiourea [67027-06-9] (3). Treatment of that intermediate with a mixture of triphenylphosphine, carbon tetrachloride, and triethylamine leads to the unsymmetrical carbodiimide, CID:20501933 (4'). Addition of cyanamid affords pinacidil (5).
^Petersen, Hans Joergen; Nielsen, C. Kaergaard; Arrigoni-Martelli, E. (1978). "Synthesis and hypotensive activity of N-alkyl-N-cyano-N'-pyridylguanidines". Journal of Medicinal Chemistry 21 (8): 773–781. doi:10.1021/jm00206a011.
^Hansen, E. T.; Petersen, H. J. (2006). "Synthesis ofN-Alkyl-N'-cyano-N″-4-pyridylguanidines from 4-Pyridyldithiocarbamic AcidviaN-Alkyl-N′-4-Pyridylthioureas, orvia4-Pyridylcyaniminothiocarbamic Acid". Synthetic Communications. 14 (13): 1275–1283. doi:10.1080/00397918408076809.
^Zhang, Hao; Liu, Rui-Quan; Liu, Ke-Chang; Li, Qi-Bo; Li, Qing-Yang; Liu, Shang-Zhong (2014). "A One-Pot Approach to Pyridyl Isothiocyanates from Amines". Molecules 19(9): 13631–13642. doi:10.3390/molecules190913631.
^Hans J. Petersen, USRE31244E (1983 to Leo Pharma AS).