Diphenyl Phosphate as an Efficient Acidic Organocatalyst for Controlled/Living Ring-Opening Polymerization of Trimethylene Carbonates Leading to Block, End-Functionalized, and Macrocyclic Polycarbonates

Abstract

The ring-opening polymerization (ROP) of cyclic carbonates with diphenyl phosphate (DPP) as the organocatalyst and 3-phenyl-1-propanol (PPA) as the initiator has been studied using trimethylene carbonate (TMC), 5,5-dimethyl-1,3-dioxan-2-one, 5,5-dibromomethyl-1,3-dioxan-2-one, 5-benzyloxy-1,3-dioxan-2-one, 5-methyl-5-allyloxycarbonyl-1,3-dioxan-2-one, and 5-methyl-5-propargyloxycarbonyl-1,3-dioxan-2-one. All the polymerizations proceeded without backbiting, decarboxylation, and transesterification reactions to afford polycarbonates having narrow polydispersity indices. In addition, 6-azido-1-hexanol, propargyl alcohol, and N-(2-hydroxyethyl)maleimide were used as functional initiators for the DPP-catalyzed ROP to produce the end-functionalized poly(trimethylene carbonate)s. For further modification of the azido end-functionlized polycarbonate, the macrocyclic poly(trimethylene carbonate) was synthesized by the intramolecular click cyclization of the α-azido, ω-ethynyl poly(trimethylene carbonate). The DPP-catalyzed ROP was applicable for the block copolymerization of TMC and δ-valerolactone or ε-caprolactone to afford poly(trimethylene carbonate)-block-poly(δ-valerolactone) and poly(trimethylene carbonate)-block-poly(ε-caprolactone), and for that of TMC and l-lactide using DPP coupled with 4-dimethylaminopyridine without quenching to produce poly(trimethylene carbonate)-block-poly(l-lactide).

A Smart Nano‐Prodrug Platform with Reactive Drug Loading, Superb Stability, and Fast Responsive Drug Release for Targeted Cancer Therapy

“…cRGD‐PS‐DM1 nano‐prodrug was readily fabricated from PEG‐ b ‐P(TMC‐ co ‐DTC) and cRGD‐PEG‐ b ‐P(TMC‐ co ‐DTC) (w/w 80/20) with simultaneous loading of DM1 via thiol–disulfide exchange reaction and disulfide cross‐linking of polymersomal membrane. PEG‐ b ‐P(TMC‐ co ‐DTC) and cRGD‐PEG‐ b ‐P(TMC‐ co ‐DTC) block copolymers were synthesized via ring‐opening polymerization of dithiolane trimethylene carbonate (DTC) with trimethylene carbonate (TMC) (Scheme S1, Supporting Information), according to previous reports with slight modifications . The M n of P(TMC‐ co ‐DTC) block can be estimated by 1 H NMR (Figure S1, Supporting Information).…”

Organophosphate-catalyzed bulk ring-opening polymerization as an environmentally benign route leading to block copolyesters, end-functionalized polyesters, and polyester-based polyurethane

“…In order to avoid metal contamination without any special purification steps, the organocatalytic approach has emerged as a powerful metal-free polymerization process in recent years. 7 Considerable effort has been directed toward the evaluation of various types of both organic acids/bases for the ROP of cyclic esters, 7-37 cyclic carbonates, [38][39][40][41][42][43] epoxides, [44][45][46][47] lactams, 48 cyclic (carbo)siloxanes, 49 cyclic phosphates, [50][51][52][53][54] etc. Regarding the ROP of cyclic esters, organic Brønsted acids, e.g., methane sulfonic acid (MSA) and triflimide, were found to be suited for the polymerization of lactones, [8][9][10][11][12][13][14][15][16][17][18][19] whereas organic bases, e.g., 1,8-diazadicyclo [5.4.0]undec-7-ene (DBU) and 4-dimethylaminopyridine (DMAP), were effective for the ROP of the lactide (LA).…”

Biodegradable polymers from monomers based on vegetable oils

“…ROP of cyclic ester monomers is one of the most effective methods to obtain homo-or copolyesters with a high molar mass and low dispersity under milder reaction conditions in comparison to condensation polymerization (Scheme 14b) [59,60]. Metallic compounds [61], guanidine based catalysts [62][63][64][65], strong acids [66][67][68], phosphazene [69], N-heterocyclic carbine [70,71], bifunctional thiourea-amine [63,72,73] and enzyme [74][75][76] have been applied as catalysts to the controlled ROP of cyclic esters. Monoglyceride from Nahar seed oil has been used for preparation of polyester resins by reaction with phthalic or maleic anhydride at high temperature.…”