N,N'-Bis(tert-butoxycarbonyl)-1H-pyrazole-1-carboxamidine → HCID 69296208, compound

Participants

Reaction Steps

Using General Procedure B: Reaction of N-(tert-butoxycarbonyl)-2-amino-acetaldehyde (0.204 g, 1.28 mmol) and (1H-Benzimidazol-2-ylmethyl)-(5,6,7,8-tetrahydro-quinolin-8-yl)-amine (0.284 g, 1.02 mmol) with NaBH(OAc)3 (0.430 g, 2.03 mmol) in CH2Cl2 (10 mL) provided 0.71 g of a yellow foam. The foam was dissolved in THF (10 mL) and treated with 6N hydrochloric acid (10 mL). The resultant solution was stirred at room temperature overnight. The solution was neutralized with solid K2CO3 (5 g), diluted with water (5 mL) and extracted with CH2Cl2 (3×20 mL). The combined organic extracts were dried (Na2SO4) and concentrated. Purification of the crude material by column chromatography on silica gel (20:1:1 CH2Cl2—CH3OH—NH4OH) provided 0.205 g (64%) of N1-(1H-Benzimidazol-2-ylmethyl)-1-(5,6,7,8-tetrahydro-quinolin-8-yl)-ethane-1,2-diamine as a yellow solid. To a solution of N1-(1H-Benzimidazol-2-ylmethyl)-N1-(5,6,7,8-tetrahydro-quinolin-8-yl)-ethane-1,2-diamine (0.205 g, 0.64 mmol) in dry THF (6 mL) was added N.N′-bis-(tert-butoxycarbonyl)-1H-pyrazole-1-carboxamidine (Tetrahedron Lett. 1993, 34, 3389.) (0.201 g, 0.64 mmol) and the resultant mixture was stirred at room temperature for 18 hours. The mixture was concentrated and the resultant oil was purified by column chromatography on silica gel (40:1:1 CH2Cl2—CH3OH—NH4OH) and provided 0.267 g (74%) of N,N′-bis(tert-butoxycarbonyl)-N″-{2-[(1H-Benzimidazol-2-ylmethyl)-(5,6,7,8-tetrahydro-quinolin-8-yl)-amino]-ethyl}-guanidine as a white foam.

Provenance & Evidence