TY - JOUR
T1 - Boron heterocycles derived from 2-guanidinobenzimidazole
AU - Andrade-López, Noemí
AU - Cartas-Rosado, Rocío
AU - García-Baéz, Efrén
AU - Contreras, Rosalinda
AU - Tlahuext, Hugo
PY - 1998
Y1 - 1998
N2 - The syntheses and structure determinations of a series of boron heterocycles derived from 2-guanidinobenzimidazole 1 are reported. Structures of new compounds, 2-guanidino-1-methyl-benzimidazole 2, diphenyl-(2-guanidinobenzimidazole-N,N′)-borate 3, diphenyl-(2-guanidino-1-methyl-benzimidazole-N,N′)borate 4, hydroxy-phenyl-(2-guanidinobenzimidazole-N,N′)borate 5, hydroxy-phenyl-(2-guanidino-1-methyl-benzimidazole-N,N′)borate 6, methoxy-phenyl-(2-guanidinobenzimidazole-N,N′)borate 7, isopropoxy-phenyl-(2-guanidinobenzimidazole-N,N′)borate 8, acetoxy-phenyl-(2-guanidinobenzimidazole-N,N′)borate 9, methoxy-phenyl-(2-guanidino-1-methyl-benzimidazole-N,N′)borate 10, dihydroxy-(2-guanidino-1-methyl-benzimidazole-N, N′) borate 16, difluoro-(2-guanidinobenzimidazole-N,N′)borate, 17, dihydroxy-(2-guanidino-1-benzimidazole-N,N′)borate potassium salt 19, diphenyl-(2-guanidinium-10H-benzimidazole-N,N′)borate hydrochloride 20, methoxy-phenyl-(2-guanidinobenzimidazole-N,N′)borate hydrochloride 21, and N10-borane-(diphenyl-2-guanidinobenzimidazole-N,N′)borate 22, were determined based on 1H, 13C, 15N, and 11B spectroscopy. The X-ray diffraction structures of 3-7, 19, and 20 were obtained. The formation of N3-borane adducts 11 and 12 derived from compounds 1 and 2, respectively, and the dihydride-(2-guanidinobenzimidazole-N,N′)borate 13 and dihydride-(2-guanidino-1-methyl-benzimidazole-N,N′)borate 14 were observed by 11B NMR. The results show that 2-guanidinobenzimidazole gives stable borate heterocycles with a delocalized π electronic system. A dynamic exchange of N-H protons was observed with preferred protonation at N-12. The new heterocycles are protonated at N-10 by acidic substances to give pyridinium-type heterocycles or can lose a proton to give iminium salts.
AB - The syntheses and structure determinations of a series of boron heterocycles derived from 2-guanidinobenzimidazole 1 are reported. Structures of new compounds, 2-guanidino-1-methyl-benzimidazole 2, diphenyl-(2-guanidinobenzimidazole-N,N′)-borate 3, diphenyl-(2-guanidino-1-methyl-benzimidazole-N,N′)borate 4, hydroxy-phenyl-(2-guanidinobenzimidazole-N,N′)borate 5, hydroxy-phenyl-(2-guanidino-1-methyl-benzimidazole-N,N′)borate 6, methoxy-phenyl-(2-guanidinobenzimidazole-N,N′)borate 7, isopropoxy-phenyl-(2-guanidinobenzimidazole-N,N′)borate 8, acetoxy-phenyl-(2-guanidinobenzimidazole-N,N′)borate 9, methoxy-phenyl-(2-guanidino-1-methyl-benzimidazole-N,N′)borate 10, dihydroxy-(2-guanidino-1-methyl-benzimidazole-N, N′) borate 16, difluoro-(2-guanidinobenzimidazole-N,N′)borate, 17, dihydroxy-(2-guanidino-1-benzimidazole-N,N′)borate potassium salt 19, diphenyl-(2-guanidinium-10H-benzimidazole-N,N′)borate hydrochloride 20, methoxy-phenyl-(2-guanidinobenzimidazole-N,N′)borate hydrochloride 21, and N10-borane-(diphenyl-2-guanidinobenzimidazole-N,N′)borate 22, were determined based on 1H, 13C, 15N, and 11B spectroscopy. The X-ray diffraction structures of 3-7, 19, and 20 were obtained. The formation of N3-borane adducts 11 and 12 derived from compounds 1 and 2, respectively, and the dihydride-(2-guanidinobenzimidazole-N,N′)borate 13 and dihydride-(2-guanidino-1-methyl-benzimidazole-N,N′)borate 14 were observed by 11B NMR. The results show that 2-guanidinobenzimidazole gives stable borate heterocycles with a delocalized π electronic system. A dynamic exchange of N-H protons was observed with preferred protonation at N-12. The new heterocycles are protonated at N-10 by acidic substances to give pyridinium-type heterocycles or can lose a proton to give iminium salts.
UR - http://www.scopus.com/inward/record.url?scp=0001218997&partnerID=8YFLogxK
U2 - 10.1002/(SICI)1098-1071(1998)9:4<399::AID-HC8>3.0.CO;2-3
DO - 10.1002/(SICI)1098-1071(1998)9:4<399::AID-HC8>3.0.CO;2-3
M3 - Artículo
SN - 1042-7163
VL - 9
SP - 399
EP - 409
JO - Heteroatom Chemistry
JF - Heteroatom Chemistry
IS - 4
ER -