Positions and stereo configurations of functional organizations (hydroxy, hydroxylmethyl and benzyl) were optimized by molecular docking
Positions and stereo configurations of functional organizations (hydroxy, hydroxylmethyl and benzyl) were optimized by molecular docking. the potency of the inhibitor is definitely fallen dramatically.[9a, 9b, 9e, 9f, 9i-k, 10c, 12] The critical part of Zn2+ ion and aspartic acid residues of the catalytic subsite for the interactions with the dGMII inhibitors was recently confirmed by quantum mechanics calculations. From crystal structures of available fruit take flight dGMII[5b, 11a] and bovine bLMan[8a] it is evident the active site of both enzymes are structurally and chemically almost identical in radius of 10 ? around Zn2+ ion co-factor. This is one of reasons why structurally small potent GMII inhibitors like swainsonine inhibit both enzymes effectively with no significant selectivity observed. Thus, our strategy in the design of a selective GMII inhibitor was based on a previous proposal,[5a, 12c] and consists of two basic points: (i) design of the core unit of the inhibitor (key interactions with catalytic subsite which is usually identical in both dGMII and bLMan); and (ii) design of structural linker (specific interactions with holding or anchor subsites of dGMII which are missing in bLMan).[5a, 8a, 11a] For these purposes, polyhydroxypyrrolidines with a) NaBH4, EtOH, rt, 2 h, 90% for 4, 98% for 5; b) MsCl, Et3N, CH2Cl2, rt, overnight, 98% for 6, 95% for 7; c) BnNH2, 120 C, 7-8 h, 87% for 8, 97% for 9; d) 6m HCl/MeOH 1:2 (v/v), rt, overnight, 62% from 8, 68% from 9; e) 1. H2, 10% Pd-C, MeOH, rt, overnight, 2. 10% HCl, 89%. Highly efficient reductive ring opening of the lactols 2 Pemetrexed disodium hemipenta hydrate and 3 with NaBH4 was performed in EtOH providing corresponding diols 4 and 5. Standard mesylation of diols 4 and 5 led smoothly to dimesylated derivatives 6 and 7. The cyclization of the dimesylate 6 with benzyl amine to access fully guarded 1,4-imino-l-lyxitol 8 was conducted previously in refluxing toluene within 24 h. Another substrate very similar to 7 was cyclized to 1 1,4-imino-l-lyxitol in neat benzyl amine under reflux for 18 h. However, optimization of reaction conditions showed that optimal reaction time and temperature for the cyclization of dimesylates 6 and 7 in neat benzyl amine were 7 h at 120 C. In addition, the work-up procedure was significantly simplified by extraction of extra BnNH2 with cold 0. 5M citric acid instead of its tedious removal by evaporation. Acid-sensitive protective groups were stable under the condition used and the ring closures were performed on a gram scale (~ 3.5 g, yield 87%). Simultaneous removal of isopropylidene and trityl/silyl protective groups from 9 under acidic conditions (6m HCl/MeOH) afforded a) RNH2, 120 C, 7-8 h, 87% for 12, 78% for 13, 77% for 14; b) 6m HCl/MeOH 1:2 (v/v), rt, overnight, 52% for 15, 54% for 16, 62% for 17. Another approach based on the removal of a) H2, 10% Pd-C, MeOH, rt, 4 h, 80%; b) RBr, K2CO3, DMF, 40 C, 4h, 89% for 19, 74% for 20; c) 6m HCl/MeOH 1:2 (v/v), rt, overnight, 73% for 21, 66% for 22. Biological assays A Pemetrexed disodium hemipenta hydrate series of seven polyhydroxylated pyrrolidines 10, 11, 15-17, 21 and 22 was evaluated towards the class II -mannosidases (GH family 38) GMIIb, LManII and JBMan and the class I -mannosidases (GH family Pemetrexed disodium hemipenta hydrate 47) AspMan. All values were essentially the same as IC50 values, not differing more than by Rabbit Polyclonal to FRS2 10%. A selective GMII inhibitor is required to exhibit none or significantly reduced inhibitory activity towards LMan. All tested polyhydroxylated pyrrolidines were found to be poor LManII inhibitors with IC50 values at the millimolar level (IC50 in range of 1.2 mM to >8mM). (Jack bean) (JBMan) (EC 184.108.40.206, GH family 38), widely used as a model for acidic -mannosides.[2b, 5f, 9e, 9q-r, 10, 12a-b] This assay provided comparable results as compared to LManII (Table 1). All tested structures did not inhibit JBMan at the 2mM concentration of the inhibitor except for 24. These results further support the validity of the selectivity index of the -1,2-mannosidase (AspMan) (EC 220.127.116.11, GH family 47). All tested structures, except for unsubstituted derivative 11 (IC50 = 1 mM), did not inhibit AspMan at the 1-2 mM concentration of the inhibitor. These results indicate that.