Resin washing

The derivatised resin product was suspended in DCM (6 mL) for 30 min, after which TEA (0.06 mL) was added and the resultant suspension was gently stirred for 15 min at ambient temperature. The suspension was filtered, the spent resin washed with DCM (5mL) and DCM MeOH (1 1, 5mL), and the combined filtrate was evaporated to dryness in vacuo to afford the title compound (25 mg, 73%) as a white crystalline solid. RP-HPLC analysis (Gl) showed the exclusive presence (>98%) of Fmoc-Val-NHOH (Rt = 5.1 min). 

The resin product was suspended in TFA (9 mL), into which was immediately added water (0.45 mL), 1,2-ethanedithiol (0.45 mL), and triisopropylsilane (0.1 mL). The mixture was left, with occasional agitation, at 30°C for 4h. The suspension was then filtered, the spent resin washed with TFA (3x1 mL) and the combined filtrate was evaporated to dryness in vacuo. The residual material was then triturated with diethyl ether (10 mL) to give a white solid, which was filtered, washed with diethyl ether (3 x 10 mL), and dried in vacuo to afford the title compound... 

Attachment of Compound 11 onto an Aminomethylated Polystyrene Resin 1 3141 A 1% cross-linked aminomethylated polystyrene resin (0.83 mmol of amino group per gram of resin, 2.41 g, 2 mmol) was placed in an ATC Model 90 reaction vessel (capacity 200 mL) and the resin washed successively with NMP, 10% DIPEA in NMP, and NMP. Then, 11 (1.41 g, 3 mmol, 1.5 equiv), HBTU (1.14 g, 3 mmol), and HOBt (0.41 g, 3 mmol) were dissolved in NMP (20 mL) in a flask, and DIPEA (0.78 mL, 4.5 mmol) was added to the soln immediately. The mixture was introduced into the reaction vessel containing the resin within 2 min after addition of DIPEA, and the entire mixture was agitated for lh at rt. The soln was drained from the reaction vessel and the resin washed well with NMP. The completion of the coupling reaction was confirmed by a ninhydrin test. 

Fmoc-Dhc(Plm)2-OH (200mg, 0.48mmol) was activated in CH2CI2/DMF (1 1 5mL) with /V-hydroxy-norborn-5-ene-2,3-dicarboxy imide (86 mg, 0.48 mmol) and DIPEA (74 pL, 0.48 mmol) at 0°C. After 5min, the mixture was added to H-Ser(tBu)-[Lys(Boc)]4- linked to 4-benzyloxybenzyl alcohol-resin (0.5 g 0.48 mmol g-1). After shaking for 2 h, the solvent was removed by filtration, and the resin washed with CH2C12 and DMF. The Fmoc-protected peptide-resin was treated with a mixture of TEA (5 mL) and thioanisole (0.5 mL) for 1 h. The resin was filtered off and the filtrate was concentrated to dryness. The Fmoc-protected hexapeptide was recrystallized (acetone) at — 20 °C. By lyophilization from tBuOH, a powder was obtained yield 80 mg (87%). 

Dry 1/f-tetrazole (0.131 g, 1.875 mmol) was added to a suspension of Tyr-peptide-Wang-resin 44 (0.075 mmol) and (tBuO)2PNEt2 (0.187 g, 0.750 mmol) in anhyd DMF (0.5 mL) and the sintered reaction vessel rotated for 3 h under N2. The soln was removed under positive N2 pressure, the resin washed with CH2C12 (3 x 3mL) and treated with TFA/Et3SiH/PhOMe (95 2.5 2.5, 2mF) for 2h. The soln was collected, the solvent removed under reduced pressure and the peptide precipitated by the addition of Et20 (10 mL). The peptide was purified by RP-HPLC [0.1 M TEA (adjusted to pH 7.5 with AcOH), 0-40% MeCN over 40min, flow rate 2.0mL-min ] and gave the product as a white powder yield 41% MALDI-MS m/z 1992.5 [M + H],... 

L-Histidine [71-00-]] M 155.2, m 287°(dec), [a] -39.7" (HjO), -hl3.0" (6M HCI). Likely impurity is arginine. Adsorbed from aqueous soln on to Dowex 50-H+ ion-exchange resin, washed with 1.5M HCI (to remove other amino acids), then eluted with 4M HCI as the dihydrochloride. Histidine is also purified as the dihydrochloride which is finally dissolved in water, the pH adjusted to 7.0, and the free zwitterionic base crystallises out on addition of EtOH. 

Cleavage from the resin (with the retention of tBu-type side chain protection) The resin (1 g) was shaken for 30 min with a mixture of AcOH, TFE, and CH2C12 (1 1 3,20 mL) and the resin removed by filtration. The procedure was repeated once more and the resin washed with the above mixture (3x5 mL) the combined filtrates were taken to dryness in vacuo after addition of toluene (20 mL). The crude product was purified by HPLC. 

Fmoc-EALAKA-Rink-resin (1.25 equiv) was allowed to swell in DMF (1.5 mL) for 1 h. The DMF was removed by filtration and the resin washed with additional DMF (1.5 mL). The resin was then treated with 20% piperidine/DMF (2 x 1.5 mL) for 10 min to remove the Fmoc protecting group, filtered, and washed with additional DMF (10 x 1.5 mL). A soln of the carboxylic acid prepared above, EDC (1 equiv), and HOBt (1 equiv) in DMF (1.5 mL) was added to the resin and the slurry was stirred for 1 h. The resin was filtered, washed with DMF (2 x 1.5 mL) followed by CH2Q2 (2 x 1.5 mL), and stored in vacuo overnight. 

The synthesis of 3 was carried out as described above with the exception that Boc-Lys(Fmoc)-OH was used in the synthesis in place of Boc-Lys(CHO)-OH (Scheme 4). Following completion of the peptide synthesis, the peptide-bound resin 6 (250 mg) was treated with piperidine/DMF (20 80, 20 mL) for 20 min, the solvent removed by filtration, and the resin washed with CH2C12(3 x 20 mL). DMF (5mL) was added to the resin followed by a CH2C12 soln (5 mL) of formic anhydride, prepared as above, and DIPEA (350 xL, 1 mmol). The resin was shaken for 20 min, the solvent removed by filtration, and the formylation repeated by the addition to the resin of DMF (5 mL), a CH2CI2 soln of formic anhydride (5 mL), and DIPEA (350 pL, 1 mmol). The resin was shaken for 15 min, filtered, washed with CH2C12 (3 x 20 mL), and the resin dried under vacuum to yield 3. The peptide-resin was converted into 4 by treatment with HF as described above. 

After washing the resin with DMA and MeOH, it was dried in vacuo to yield 640 mg peptide-resin. A part (350 mg) of the resin sample was treated with 95% TFA (5mL) for 90 min to deprotect the Glu(OtBu) and remove the peptide from its resin support. The suspension was filtered, the resin washed with TFA (15mL), and the combined filtrates were triturated with Et20 (3x20mL) and dried in vacuo over silica drying gel. The S-acetyl di-K2K core 37 was used without further purification. 

Solid-Phase Synthesis Terminated by Diketopiperazine Cyclative Cleavage (Scheme 1). The Fmoc-L-Trp resin (loading 0.5 mmol/g) is first deprotected with 20% piperidine in DMF for 20 min, and the resin washed and dried. The resin ( 1 g, 0.62 mmol/g) is shaken with benzaldehyde (0.63 ml, 10 molar equiv.) and trimethyl orthoformate (1.36 ml, 20 molar equiv.) in 7 ml CH2C12 overnight, followed by washing and drying to give resin 1. 

Mitsunobu Reaction for Exocyclic N2-Alkylation on a Purine Scaffold (Fig. 16).47 2,6-Di-tert-butyl-4-methylpyridine (1.54 g, 7.5 mmol, 0.3 M) is added to freshly distilled CH2C12 (25 ml) at 0° under N2. To this solution is added trifluoroacetic anhydride (706 pi, 5.0 mmol, 0.2 M) and the mixture is stirred for 5-10 min. The solution is then transferred to the resin 83 and the flask is vortexed and vented several times to relieve pressure. The flask is shaken for 6-12 h after which the solvent is removed and the resin washed with dry CH2C12 (5 x 25 ml) with vortexing between each rinse. The resulting resin 84 is dried. 

After each deprotecting and washing step, following protocol A or B, the next amino acid in sequence was added and the resin washed with CH2CI2 3 times/1 min, MeOH 4 times/1 min, DMF 2 times/1 min and CH2CI2 4 times/1 min. 

Amino-6-chloro-9-[2-(2,2-dimethyl-l,3-dioxan-5-yl)-ethyl]purine (0.59 g, 1.9 mmol) in hydrochloric acid (1.0 M, 4 ml) was stirred at 60°C for 24 hours. The solution was diluted with water and neutralised with Amberlite IR 45. The mixture was filtered, the resin washed with water and the solvent evaporated under reduced pressure. The residue was recrystallised from water to afford 9-(4-hydroxy-3-hydroxymethylbut-l-yl)guanine (238 mg, 49%), melting point 275°-277°C. 

Tablet feed Rapidly dispersible Plastics, resins, washing...

Elution. After the actinides have been loaded and the resin washed, the (short) loading column effluent is routed to the (long) separation column, and the high-pressure pump is used to transfer eluent through the columns at a rate of 1.0 L/h (a superficial velocity of 2.0 mm/s through the elution column). 

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