Syntheses of 1 → 3 branched isocyanate monomers for dendritic construction

Abstract

Abstract-The synthesis of a novel series of 1 → 3 C-branched, isocyanate-based building blocks (monomers) useful for the rapid construction of dendritic architectures is reported. More specifically, the preparation of di-t-butyl 4-isocyanato-4- (9), and dimethyl 6-isocyanato-6-(4-carbomethoxy-2-oxabutyl)-4,8-dioxaundecanedioate (11), via treatment of the corresponding amines with triphosgene, is described. Characteristic features of each monomer include a triad of protected functionality connected to a single, air-stable isocyanate moiety. Isocyanate stability is postulated to arise from the close proximity of the tertiary alkyl branching center. This series of dendritic building blocks facilitates the introduction of a variety of functional groups, such as alcohol, amines, carboxylic acids, esters, nitriles, and ethers, onto the surface of dendrimers as well as other suitable materials. Isocyanate utility is demonstrated by reaction of a DSM-based, 32-amine-terminated dendrimer with the triscarbamate isocyanate monomer (7d) to afford a poly(t-butyl carbamate)-'coated' dendrimer (12).

Regioselective Dendritic Functionalization of Cellulose

“…The other carbon signals for the dendritic moiety appeared in the spectra in addition Figure 1. 13 C NMR spectra of the dendritic cellulose carbamates with 1st (4), 2nd (5), and 3rd (6) generation aminotriester-based (Behera's amine [13,14] ) dendrons. to the signals of the asymmetric glucose units (AGUs) of cellulose at 102.6 (C-1), 75.4 (C-2,3), 73 (C-5), and 61 (C-6) ppm.…”

Dendrimer construction and macromolecular property modification via combinatorial methods

“…30,37,38 Figure 1 shows the various isocyanate and functional amine monomers that were used for combinatorial tier construction. Isocyanate monomers 1-5 were prepared as previously described; amines 7-9 are commercially available.…”

Synthesis, Critical Micelle Concentrations, and Antimycobacterial Properties of Homologous, Dendritic Amphiphiles. Probing Intrinsic Activity and the “Cutoff” Effect

“…Weisocyanate was prepared as described. 46 Analytical thin layer chromatography was performed on polyester-coated silica gels (60 Å) and detected by treating with 10% ethanolic phosphomolybdic acid reagent (20 wt % solution in ethanol). Flash column chromatography was carried out on 60 Å ultrapure silica gels.…”