606145-78-2Relevant articles and documents
Highly Chemoselective, Transition-Metal-Free Transamidation of Unactivated Amides and Direct Amidation of Alkyl Esters by N-C/O-C Cleavage
Li, Guangchen,Ji, Chong-Lei,Hong, Xin,Szostak, Michal
supporting information, p. 11161 - 11172 (2019/08/07)
The amide bond is one of the most fundamental functional groups in chemistry and biology and plays a central role in numerous processes harnessed to streamline the synthesis of key pharmaceutical and industrial molecules. Although the synthesis of amides is one of the most frequently performed reactions by academic and industrial scientists, the direct transamidation of tertiary amides is challenging due to unfavorable kinetic and thermodynamic contributions of the process. Herein, we report the first general, mild, and highly chemoselective method for transamidation of unactivated tertiary amides by a direct acyl N-C bond cleavage with non-nucleophilic amines. This operationally simple method is performed in the absence of transition metals and operates under unusually mild reaction conditions. In this context, we further describe the direct amidation of abundant alkyl esters to afford amide bonds with exquisite selectivity by acyl C-O bond cleavage. The utility of this process is showcased by a broad scope of the method, including various sensitive functional groups, late-stage modification, and the synthesis of drug molecules (>80 examples). Remarkable selectivity toward different functional groups and within different amide and ester electrophiles that is not feasible using existing methods was observed. Extensive experimental and computational studies were conducted to provide insight into the mechanism and the origins of high selectivity. We further present a series of guidelines to predict the reactivity of amides and esters in the synthesis of valuable amide bonds by this user-friendly process. In light of the importance of the amide bond in organic synthesis and major practical advantages of this method, the study opens up new opportunities in the synthesis of pivotal amide bonds in a broad range of chemical contexts.
PYRROLOPYRIMIDINE DERIVATIVES AS MODULATORS OF MULTI-DRUG RESISTANCE (MDR)
-
Page 33, (2010/02/10)
A compound which is a pyrrolopyrimidine of formula (I) wherein R1 is selected from H, Cl-C6 alkyl which is unsubstituted or substituted, (CH2)nAr1, (CH2)pNR4R5, halogen and (CH2)pX; R2 is CH2)pArl; R3 is selected from H, Cl -C6 alkyl which is unsubstituted or substituted, (CH2)pZ and (CH2)pArl; P is an unsaturated 5, 6, or 7 membered carbocyclic or heterocyclic ring which is unsubstituted or substituted; R4 and R5 which are the same or different are selected from H, Cl -C6 alkyl which is unsubstituted or substituted, (CH2)nC3-C10 cycloalkyl, (CH2)nAr1 , and (CH2)nOR6, or R4 and R5 together with the nitrogen atom to which they are attached, form a saturated five or six membered nitrogen containing heterocyclic ring which may contain one extra heteroatom selected from 0, N and S and which is unsubstituted or substituted; R6 is selected from H, Cl -C6 alkyl which is unsubstituted or substituted, C3-C10 cycloalkyl, (CH2)nOC1-C6alkyl which is unsubstituted or substituted, (CH2)nO(CH2)nAr1 , (CH2)nCO2C1-C6,alkyl which is unsubstituted or substituted and (CH2)nAr1; X is selected from CN, azide, (CH2)nNHSO2R6 and (CH2)nNHCOR6; Z is selected from CN, CO2R6 and CONR4R5; Ar1 is the same or different when more than one is present within a given substituent group and is an unsaturated C6-C10 membered carbocylic group or an unsaturated 5-11 membered heterocycle, either of which is unsubstituted or substituted; p is an integer of 1 to 6; n is the same or different when more than one is present within a given substituent group and is 0 or an integer of 1 to 6; with the proviso that the pyrrolepyrimidine compound of formula (I) is other than 1-(4-benzyl-piperazin-1-yl)-9H-2,4,9-triaza-fluorene; and the pharmaceutically acceptable salts thereof, have activity as inhibitors of MRP (multidrug resistant protein) and may thus be used to modulate multidrug resistance, for instance in potentiating the cytotoxicity of a chemotherapeutic agent.
