Activity of 6-aryl-pyrrolo[2,3-d]pyrimidine-4-amines to Tetrahymena

A series 6-aryl-pyrrolo[2,3-d]pyrimidine-4-amines (43 compounds), some of which are epidermal growth 22 factor tyrosine kinase inhibitors, were tested for their protozoal toxicity using an environmental Tetrahy- 23 mena strain as model organism. The protozoacidal activity of the analogues was found to be highly 24 dependent on a 4-hydroxyl group at the 6-aryl ring, and a chiral 1-phenylethanamine substituent in posi- 25 tion 4. Further, the potency was affected by the aromatic substitution pattern of the phenylethanamine: 26 the unsubstituted, the meta-fluoro and the para-bromo substituted derivatives had the lowest minimum 27 protozoacidal concentrations (8–16 lg/mL). Surprisingly, both enantiomers were found to have high 28 potency suggesting that this compound class could have several modes of action. No correlation was 29 found between the compounds protozoacidal activity and the in vitro epidermal growth factor receptor 30 tyrosine kinase inhibitory potency. This suggests that the observed antimicrobial effects are related to 31 other targets. Testing towards a panel of kinases indicated several alternative modes of actio

A highly selective purine-based inhibitor of CSF1R potently inhibits osteoclast differentiation

The colony-stimulating factor 1 receptor (CSF1R) plays an important role in the regulation of many inflammatory processes, and overexpression of the kinase is implicated in several disease states. Identifying selective, smallmolecule inhibitors of CSF1R may be a crucial step toward treating these disorders. Through modelling, synthesis, and a systematic structure-activity relationship study, we have identified a number of potent and highly selective purine-based inhibitors of CSF1R. The optimized 6,8-disubstituted antagonist, compound 9, has enzymatic IC50 of 0.2 nM, and displays a strong affinity toward the autoinhibited form of CSF1R, contrasting that of other previously reported inhibitors. As a result of its binding mode, the inhibitor shows excellent selectivity (Selectivity score: 0.06), evidenced by profiling towards a panel of 468 kinases. In cell-based assays, this inhibitor shows dose-dependent blockade of CSF1-mediated downstream signalling in murine bone marrow-derived macrophages (IC50 = 106 nM) as well as disruption of osteoclast differentiation at nanomolar levels. In vivo experiments, however, indicate that improve metabolic stability is needed in order to further progress this compound class

Activation of multiple stress responses in Staphylococcus aureus substantially lowers the minimal inhibitory concentration when combining two novel antibiotic drug candidates

The past few decades have been plagued by an increasing number of infections caused by antibiotic resistant bacteria. To mitigate the rise in untreatable infections, we need new antibiotics with novel targets and drug combinations that reduce resistance development. The novel β-clamp targeting antimicrobial peptide BTP-001 was recently shown to have a strong additive effect in combination with the halogenated pyrrolopyrimidine JK-274. In this study, the molecular basis for this effect was examined by a comprehensive proteomic and metabolomic study of the individual and combined effects on Staphylococcus aureus. We found that JK-274 reduced activation of several TCA cycle enzymes, likely via increasing the cellular nitric oxide stress, and BTP-001 induced oxidative stress in addition to inhibiting replication, translation, and DNA repair processes. Analysis indicated that several proteins linked to stress were only activated in the combination and not in the single treatments. These results suggest that the strong additive effect is due to the activation of multiple stress responses that can only be triggered by the combined effect of the individual mechanisms. Importantly, the combination dose required to eradicate S. aureus was well tolerated and did not affect cell viability of immortalized human keratinocyte cells, suggesting a species-specific response. Our findings demonstrate the potential of JK-274 and BTP-001 as antibiotic drug candidates and warrant further studies

Comparison of Students' Perceived Learning in Two Similar Lab Courses with Different Teaching Staffs

At the Norwegian University of Science and Technology (NTN), two subjects with similar chemistry laboratory exercises have different practices with respect to the use of permanent and temporary staffs. In an ever-increasing focus on costs related to this type of teaching, we have investigated this difference and examined the students' perceived learning outcomes in two similar courses with different teaching practices. The results show that the students in both courses find the lab exercises relevant to the subjects and that they receive good guidance during the practical work. The most important findings reported by the students are related to the feedback students receive on their reports and most importantly how they choose to use this feedback. The students in the lab courses with permanent employees seem to use feedback more actively compared to the students in the courses with temporary employees. This might also be related to how much they engage in their own written reports. While one student group is given an allocated time to complete their report forms and hand them in during the lab hours; the other student group complete their reports in their own pace outside of the mandatory lab hours. This difference in how the written reports are completed might have an impact on the degree of reflection and learning outcome for the students. These findings further emphasize the importance of well-structured laboratory sessions with clearly communicated learning objectives as key to obtain the wanted learning outcomes for all STEM subjects with practical training. In conclusion, the use of permanent teaching assistants in laboratory teaching enhances the students' perceived learning in chemistry laboratory exercises and the present study further accentuates the need for motivated laboratory teaching assistants for the given feedback to be productiv

Is literature data useful for identifying enzyme catalysts for new substrates? A case study on reduction of 1-aryl-2-alkanoates

The use of literature data to identify catalysts for a novel transformation is a commonly used approach. Herein, we have evaluated if this is a viable strategy in enzyme catalysis, using asymmetric reduction of 1-aryl-2-alkanoates as a model system. The study, which includes data from 24 ketone substrates and 108 enzymes, clearly identifies pitfalls with this approach, but anyhow shows that literature data is highly useful for identification of enantioselective catalysts. By combining data for selectivity and rate useful catalyst for converting different substrates to their corresponding (R)- and (S)-enantiomers are highlighted

One-step lipase-catalysed preparation of eslicarbazepine

The antiepileptic eslicarbazepine (S-licarbazepine) has been prepared in one step from its racemic form RS-licarbazepine via lipase catalysed kinetic resolution. A novel stereoselective simultaneous HPLC separations of RS-licarbazepine (1) and its racemic esters RS-2–5 have been developed on Lux® cellulose-2 column using cyclohexane/ethanol 1/1 v/v as mobile phase. The developed enantioselective HPLC separations have been utilized for monitoring of lipase catalyzed kinetic resolution of RS-licarbazepine (1). Lipase catalysed trans-esterification and hydrolysis reactions have been performed. Four different esters (acetate (2), propionate (3), butyrate (4) and benzoate (5)) have been investigated for both trans-esterification and hydrolysis using ten lipases from versatile origins. The best enantioselectivity was shown by trans-esterification of RS-licarbazepine with vinyl benzoate in MtBE as solvent and lipase from Candida rugosa where the pharmacologically active enantiomer, S-(+)-licarbazepine, has been accomplished [E = 31, ee = 97%, yield 84%, α20D = +105, c 0.001 g mL−1, CH3OH]. Molecular docking attributed the high enantioselectivity of the transesterification when using Candida rugosa lipase to unfavorable ligand contacts between the S-enantiomer and phenylalanine 296

Directed Lithiation of Protected 4-Chloropyrrolopyrimidine: Addition to Aldehydes and Ketones Aided by Bis(2-dimethylaminoethyl)ether

Pyrrolopyrimidines are important scaffolds for the preparation of bioactive molecules. Therefore, developing efficient and flexible ways for selective functionalization of the pyrrolopyrimidine skeleton is of interest. We have investigated lithiation-addition at C-6 of protected 4-chloro-7H-pyrrolo [2,3-d]pyrimidine as a route to new building blocks for medicinal chemistry. It was found that bis(2-dimethylaminoethyl) ether as an additive increased the yield in the additional reaction with benzaldehyde. Deuterium oxide quench experiments showed that this additive offered both a higher degree of lithiation and increased stability of the lithiated intermediate. The substrate scope of the protocol was investigated with 16 aldehydes and ketones, revealing the method to be excellently suited for reaction with aldehydes, cyclohexanone derivatives and 2,2,2-trifluoroacetophenone, while being less efficient for acetophenones. Yields in the range of 46–93% were obtained

The enantioselectivity of reduction of ethyl 4-halo-3-oxobutanoate catalyzed by Geotrichum candidum depends on the cofactor

Enantioselective reductions of ethyl 3-oxobutanoates with fermenting cells or acetone treated cells of Geotrichum candidum gave 3-hydroxyesters with different ee and different predominant configurations depending on reaction conditions. Ethyl 4-bromo-3-oxobutanoate was reduced with APG4 and NADH to give predominantly ethyl (R)-4-bromo-3 hydroxybutanoate while the (S)-configuration was predominant when NADPH was the cofactor. Moreover, when the catalyst was heated before the reaction, the ee was increased indicating that the enzyme giving the (S)-alcohol is more thermolabile than the other

Directed Lithiation of Protected 4-Chloropyrrolopyrimidine: Addition to Aldehydes and Ketones Aided by Bis(2-dimethylaminoethyl)ether

Pyrrolopyrimidines are important scaffolds for the preparation of bioactive molecules. Therefore, developing efficient and flexible ways for selective functionalization of the pyrrolopyrimidine skeleton is of interest. We have investigated lithiation-addition at C-6 of protected 4-chloro-7H-pyrrolo [2,3-d]pyrimidine as a route to new building blocks for medicinal chemistry. It was found that bis(2-dimethylaminoethyl) ether as an additive increased the yield in the additional reaction with benzaldehyde. Deuterium oxide quench experiments showed that this additive offered both a higher degree of lithiation and increased stability of the lithiated intermediate. The substrate scope of the protocol was investigated with 16 aldehydes and ketones, revealing the method to be excellently suited for reaction with aldehydes, cyclohexanone derivatives and 2,2,2-trifluoroacetophenone, while being less efficient for acetophenones. Yields in the range of 46–93% were obtained