1-Aminocyclobutanecarboxylic acid → (E)-3-[2-(1-aminocyclobutyl)-1-methyl-1H-benzoimidazol-5-yl]acrylic acid methyl ester

Participants

Reaction Steps

(E)-3-(3-Amino-4-methylaminophenyl)acrylic acid methyl ester 2-4 from Example 2 (40 mg, 0.194 mmol) was suspended in CH2Cl2 (3 mL) and 1-aminocyclobutanecarboxylic acid chloride hydrochloride, prepared from 1-aminocyclobutanecarboxylic acid following an adaptation of the procedure described by E. S. Uffelman et al. (Org. Lett. 1999, 1, 1157), (31 mg, 0.18 mmol) was added. The reaction mixture was stirred at room temperature for 2 hours and then concentrated to obtain a white solid. The solid was then dissolved in acetic acid (5 mL) and heated to 60° C. for 20 hours. The reaction crude was diluted with aqueous saturated NaHCO3, extracted with CH2Cl2 (2×50 mL) and brine, the organic layer was dried over anhydrous MgSO4 and the solvent was removed under reduced pressure to give (E)-3-[2-(1-aminocyclobutyl)-1-methyl-1H-benzoimidazol-5-yl]acrylic acid methyl ester 3-1 as a light brown foam (53 mg).

Provenance & Evidence