Synthesis of Unsymmetrical Pyrrolo[3,2‐b]pyrrole‐2,5‐diones.

Abstract

Synthesis of Unsymmetrical Pyrrolo[3,2-b]pyrrole-2,5-diones. -Unsymmetrically disubstituted oxalic acid-bis(imidoyl) dichlorides such as (IV) are prepared for the first time. They are used in a one-pot synthesis of pyrrolopyrroles (VI). Additionally, the synthesis of a 2,2'-bisquinazolinone (VIII) is demonstrated. -(LANGER*, P.; HELMHOLZ, F.; SCHROEDER, R.; Synlett 2003, 15, 2389-2391; Inst. Chem.

Synthesis and Optical Properties of Pyrrolo[3,2-b]pyrrole-2,5(1H,4H)-dione (iDPP)-Based Molecules

“…The structure and synthesis of iDPP n Ts T1–T3 with a different number of thiophene rings in the backbone are shown in Scheme . For preparation of T1–T3 we used a synthetic strategy reported by Langer et al , To increase the solubility of the compounds we included 2-ethylhexyloxy substituents on the N -phenyls. The corresponding aniline derivative 2 was synthesized from commercial 4-acetoamidophenol using Williamson ether synthesis, followed by deacylation of the amide using concentrated hydrochloric acid in ethanol resulting in 2 .…”

“…The iDPP polymers reported in a recent patent were prepared by Stille couplings using Pd 2 (dba) 3 /(o-tol) 3 P as a catalytic system. 45 The structure and purity of the intermediate and final compounds were determined by MALDI-TOF, 13 C NMR, and 1 H NMR techniques.…”

“…The first synthesis of the symmetrical and asymmetrical pyrrolo[3,2- b ]pyrrole-2,5-diones (iDPPs, Ar 1 = Ar 2 = aryl and R 1 = R 2 = H, Figure ) has been reported by Fürstenwerth, starting from pulvinic acid derivatives using harsh reaction conditions in low reaction yields due to formation of side products. A number of symmetrical N -arylated iDPPs (R 1 = R 2 = Ar and Ar 1 = Ar 2 , Figure ) have been synthesized by reacting aromatic ester carbanions with aromatic oxalic acid–bis(imidoyl)dichlorides that can be obtained in a one-pot reaction from aromatic amines, oxalyl chloride, and PCl 5 . , Asymmetrical N -arylated iDPPs (R 1 , R 2 = aryl with R 1 ≠ R 2 and Ar 1 = Ar 2 ) have been prepared by the same synthetic strategy but using asymmetrical oxalic acid–bis(imidoyl)dichlorides which can be prepared in a few steps starting from commercial ethyl-2-chloro-2-oxoacetate and different derivatives of aniline …”

“…10,11 Asymmetrical N-arylated iDPPs (R 1 , R 2 = aryl with R 1 ≠ R 2 and Ar 1 = Ar 2 ) have been prepared by the same synthetic strategy 12 but using asymmetrical oxalic acid−bis(imidoyl)dichlorides which can be prepared in a few steps starting from commercial ethyl-2-chloro-2-oxoacetate and different derivatives of aniline. 13 The nature of the lowest excited state in DPP and iDPP derivatives is of importance for application in opto-electronics. While normal DPPs are renowned for their bright fluorescence in solution, 14,15 many structurally related chromophores show hardly any photoluminescence activity.…”