Synthesis of α-carboranyl-α-acyloxy-amides as potential BNCT agents

Abstract

Novel α-carboranyl-α-acyloxy-amides were prepared as potential BNCT agents utilizing three component Passerini reaction. Preliminary cytotoxicity of the representative compounds on two brain tumor cell lines (U-87 and A-172) showed no effect on cell viability; an essential requirement for utility as potential BNCT agents.

Synthesis and Biological Evaluation of Novel Benzoxaboroles as Potential Antimicrobial and Anticancer Agents

“…The reaction of boronoaldehydes 6a , 6b , 6c with phenyl acrylate proved facile, and the products benzoxaboroles 7d , 7e , 7f were isolated in good yields (entries 4–6, Table ). Similarly, the BH reaction of boronobenzaldehydes 6a , 6b , 6c with other activated alkenes such as methyl vinyl ketone and acrylonitrile provided benzoxaboroles 7g , 7h , 7i (entries 7–9, Table ) and 7j , 7k , 7l (entries 10–12, Table ), respectively, in moderate to good overall yields (Table ) 6a …”

“…We then utilized the boronoaldehyde for Passerini reaction to synthesize α‐amido benzoxaboroles 15a , 15b , 15c , 15d , 15e , 15f , 15g , 15h , 15i . The reaction of aldehyde 6a with benzyl isonitrile 14a , cyclohexyl isonitrile 14b , and t butyl isonitrile 14c and the product boroles 15a , 15b , 15c were obtained in good yields upon silica gel column chromatography (Scheme ) 6b . Similarly the aldehydes 6b , 6c were also reacted with the three isonitriles 14a , 14b , 14c to provide the corresponding benzoxaboroles 15d , 15e , 15f , 15g , 15h , 15i in good yields (Scheme ).…”

“…The requisite bromides were prepared in two steps using literature procedure starting from BH reaction of formaldehyde 8a and acetaldehyde 8b with methyl acrylate followed by bromination . Reaction of allyl bromides 9a , 9b with boronoaldehydes 6a , 6b , 6c in the presence of zinc and saturated NH 4 Cl under standard Barbier conditions provided the homologated benzoboroxoles 10a , 10b , 10c , 10d , 10e , 10f in good yields (Scheme ) 6a . The products benzoboroxoles 10a , 10b , 10c , 10d , 10e , 10f obtained from acetaldehyde‐derived BH bromide 12b were obtained in predominantly syn stereochemistry as was confirmed by single crystal X‐ray analysis of 10d (Fig.…”

“…We have been working on the development of novel synthetic methodologies for the synthesis of functionalized benzoxaboroles as potential therapeutic agents . Previously, we have synthesized several benzoxaboroles using Baylis–Hillman (BH), 6a Barbier allylation, 6a and Passerini reaction 6b protocols. In continuation of our interest on the development of structurally diverse benzoboroxoles, we synthesized several novel derivatives starting from 2‐formylphenylboronic acid utilizing aldol reaction as the key step.…”

Boron‐Containing Lipids and Liposomes: New Conjugates of Cholesterol with Polyhedral Boron Hydrides

“…[35][36][37] Twom ain different types of boron-based lipids which are able to incorporate into the liposomal bilayer were proposed. The first in some one mimics way phosphatidylcholine lipids, [38][39][40][41][42][43][44][45][46] where the second one includes cholesterol derivatives of carboranes [47][48][49][50][51] or carborane cholesterol mimics. [52] Af ew examples of closo-dodecaborate [53] and metallacarborane [54] based cholesterol-type lipids were reported as well.…”