A Novel Approach to the Syntheses of Functionalized, Water-Soluble Icosahedral Carboranyl Anions. Crystal Structure of Methyl N-[(Trimethylamineboryl)carbonyl]-L-tyrosinate: A Synthon for Novel Carboranylpeptides

Abstract

New functionalized water-soluble carboranyl anions have been prepared from ortho-carborane through lithiation and subsequent derivatization. The reaction of Li2[1,2-C2B10H10] with Me3NBH2X produced the carboranylborane dianions, [1,2-(BH2X)-1,2-C2B10H10]2- (X = H (2a), CN (2b), COOMe (2c), COOH (2d)), while the reaction of [1-R-2-Li-C2B10H10]- with Me3NBH2X produced the monoanions [1-R-2-BH2X-C2B10H10]- (R = C6H5, X = H (2e), CN (2f), COOH (2h), COOCH3 (2g), CONHCH(CH2OH)COOMe (2i), CONHCH(CHMe2)COOMe (2j), CONHCH(4-CH2C6H4OH)- COOMe (2k); R = Me, X = H (2l), COOH (2m)). These water-soluble carboranylboranes have the potential of being effective hydrophilic boron neutron capture therapy (BNCT) agents. The crystal structure of the peptide precursor Me3NBH2CONHCH(4-CH2C6H4OH)COOMe (3b) which showed a special promise as a BNCT agent is also described.

Substituted Carborane-Appended Water-Soluble Single-Wall Carbon Nanotubes: New Approach to Boron Neutron Capture Therapy Drug Delivery

“…All data are consistent with the formulations shown in Scheme . The 13 C NMR spectra show the presence of the carborane cage carbons at δ 73−83 ppm, which is in the range of the reported C cage resonances of other C 2 B 10 systems, in addition to those of the C cage -substituted moieties. The 11 B NMR spectra are also in accord with literature values. , In addition to showing infrared peaks at 2587 cm -1 , assigned to the B−H bond stretching, compounds IIIa and IIIb show strong absorptions at 2098 cm -1 due to the NN stretching mode of vibrations (Figure ).…”

“…The sequence of reactions leading to the side-wall functionalization of the SWCNTs with the substituted carborane units is shown in Scheme . The formation of the lithium salt of [1-R- closo- 1,2-C 2 B 10 H 10 ] - (R = Me, Ph) followed literature procedures . The monolithium compound was not isolated but was reacted, in situ, with 1-chloro-4-iodobutane to give a mixture of 1-R-2-(CH 2 ) 4 Cl-1,2-C 2 B 10 H 10 and 1-R-2-(CH 2 ) 4 I-1,2-C 2 B 10 H 10 in Cl/I molar ratios of 1:0.89 and 1:0.82 for R = Me and Ph, respectively.…”

Syntheses and Characterization of o‐Carboranes Containing Fused exo‐Polyhedral Di‐ and Triboraheterocycles

“…The synthesis of C ‐phenylboryl‐ o ‐carborane derivatives and their hydrolysis have been described 9. Borates of the types [1, 2‐(H 2 BX) 2 C 2 B 10 H 10 ] 2– and [1‐R‐2‐H 2 BXC 2 B 10 H 11 ] – (R = Me or Ph, X represents an organic substituent) were also reported 10. Organic‐inorganic hybrid ligands, in which the o ‐carborane polyhedra and cyclic π ligands11 are bridged by a boryl group were studied.…”

Synthesis and examination of amine-cyanocarboxyboranes, the boron analogues of α-cyanocarboxylic acids: X-ray structural study of the first lactam containing a boron atom in the lactam ring

“…In addition, their mode of action has also been studied [12,14]. Recently these molecules [15] as well as carboranyl salts containing BH 2 X (X = CN, COOH, COOMe) groups [16] have also been suggested as possible boron carriers to tumor cells for boron neutron capture therapy, although molecules with only one boron atom appear to be less suited for BNCT purposes.…”