2002;277:43648. in concert with JNK-2 has been suggested to play a central part in the development of obesity-induced insulin resistance which implies restorative inhibition of JNK1 may provide a potential remedy in type-2 diabetes mellitus.4,5 JNK2 has been described in the pathology of autoimmune disorders such as rheumatoid arthritis and asthma, and it also has been implicated to play a role in cancer, as well as with a broad range of diseases with an inflammatory component.6-10 JNK3 has been shown to mediate neuronal apoptosis which makes inhibiting this isoform a encouraging therapeutic target for neurodegenerative diseases such as Parkinson’s disease, Alzheimer’s disease and additional CNS disorders.11-13 Therefore, developing JNK inhibitors as therapeutics offers gained substantial interest over the past few years.14-21 With this Letter we statement a novel series of pan-JNK MC-Sq-Cit-PAB-Dolastatin10 inhibitors recognized inside a high-throughput-screening marketing campaign of our in-house sample collection. Compound 1 was identified as an ATP-competitive pan-JNK inhibitor with IC50 ideals 1.0 M and 0.49 M versus JNK3 and JNK1, respectively, with no inhibition against p38 ( 20 M). Urged from the lead candidates structural simplicity and by its encouraging degree of selectivity against p38, we initiated lead optimization. Herein we statement the synthesis, characterization, and SAR (Structure-Activity-Relationships) of piperazine 1 (observe Fig. 1). Open in a separate window Number 1 In-house high-throughput-screening hit (1: JNK3 1.0 M, JNK1 0.49 M, p38 20 M). The synthesis of analogs of 1 1 are defined in Plan 1. A 1,2-disubstituted-3-nitrobenzene (2) was treated having a piperazine or piperidine in toluene and refluxed over night. The producing nitrobenzene was reduced to the aniline (3) via hydrogenation or SnCl2 Goat polyclonal to IgG (H+L)(HRPO) and then treated with the various acidity chlorides in pyridine to give R1-derivatized compounds (Furniture 1-?-3,3, 4, 6, and 9). Further SAR of the piperazine was accomplished by BOC-cleavage and funtionalization MC-Sq-Cit-PAB-Dolastatin10 to afford analogs of 4 (Table 1). Open in a separate window Plan 1 Reagents and conditions: (a) piperazine, 180 C, neat (b) Boc2O (c) H2, Pt-O (d) MC-Sq-Cit-PAB-Dolastatin10 5-bromo-furoyl chloride, CH2Cl2 (e) trifluoroacetic acid, CH2Cl2 (f) R1Y (Y = leaving group); (g) 1-allylpiperazine, toluene, reflux (h) SnCl2, concd HCl (i) R2COCl, pyridine, 0 C (j) 1,4-dioxa-8-azaspiro[4.5]decane, neat (k) 5-R3-furoyl chloride, CH2Cl2, pyridine. Table 1 em N /em -Acyl- em N /em -aryl piperazines thead th align=”remaining” valign=”middle” rowspan=”1″ colspan=”1″ Compd /th th align=”remaining” valign=”middle” rowspan=”1″ colspan=”1″ R /th th align=”remaining” valign=”middle” rowspan=”1″ colspan=”1″ R1 /th MC-Sq-Cit-PAB-Dolastatin10 th align=”remaining” valign=”middle” rowspan=”1″ colspan=”1″ JNK322 IC50a (M) /th th align=”remaining” valign=”middle” rowspan=”1″ colspan=”1″ JNK122IC50a(M) /th /thead 4aClH9.94.14bClMe1.20.361ClEthyl1.10.364cCl em n /em -Pr0.90.634dCl em i /em -Pr2.21.54eClAllyl0.330.244fCl2-Methallyl0.540.404gClPropargyl0.160.144hClCyclopropyl0.960.184iClFuranylmethyl0.250.274jClBenzyl1.10.884kClPhenethyl1.40.904lCl2-Pyridyl1.01.24mClAcetyl0.810.604nClTrifluoroacetyl 20 204oClBoc 206.34pMeAllyl0.200.184qFPropargyl0.290.114rBrAllyl 20 204sCF3Allyl 20 204tPhAllyl 20* 204uNHPhAllyl 20* 20 Open in a separate window aThe ideals are averages of two or more experiments. All standard deviation 20%. *A quantity of aryl and heteroaryl substituents tested, all 20 M. Table 3 Aryl piperidines thead th align=”remaining” valign=”middle” rowspan=”1″ colspan=”1″ Compd /th th align=”remaining” valign=”middle” rowspan=”1″ colspan=”1″ R3 /th th align=”remaining” valign=”middle” rowspan=”1″ colspan=”1″ JNK3 IC50a (M) /th th align=”remaining” valign=”middle” rowspan=”1″ colspan=”1″ JNK1 IC50a (M) /th /thead 9bBr0.060.099dCl0.080.049eF0.410.219fCN0.210.239gMe0.530.339hCHF20.350.269iEt1.01.49jPropynyl0.110.119kBn4.83.29lOMe0.620.459mNHAc11.05.89nNHPh 20 20 Open in a separate window aValues are means of three experiments. All standard deviation 20%. Compared to the lead structure (1), the unprotected piperazine (4a) was a 10-collapse less potent JNK3 inhibitor while simple alkyl substitutions (4b-d) offered little switch in potency (Table 1). However, small side chains which contain unsaturation or sp-2 character seemed to provide a small boost in potency (up to six-fold) (4e-i). Its unclear if this was the result of a favorable pi-stacking connection that was no longer available to the sterically larger benzyl or phenethyl analogs. Direct arylation (4l) or acylation of the piperazine offered no inhibition advantage (4m-o). As for varying the 3-substituent within the phenyl ring, it seemed like small groups were tolerated (Cl, F, Me), but larger groups led to loss of activity (4r-u). Like lead hit 1, all analogs showed no selectivity between JNK3 and JNK1, and if anything, were slightly more potent against JNK1. All compounds also showed no inhibition against p38 (data not demonstrated). SAR of the MC-Sq-Cit-PAB-Dolastatin10 aniline amide group proved to be equally annoying (Table 2). We desired to find a replacement for the electron rich furan group with something that might be more metabolically stable, however attempts to modify the 5-bromofuran moiety and maintain potency were hard.23 Of all the substitutions examined, the only sub-micromolar inhibitor was 5-bromothiazole 6b. All others led.