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A library of compounds in which R4 was various groups having the formula [CONHR ?] was prepared by the process described above using 4-fluoro-3-nitrobenzoic acid, as follows: [72] Aldehyde resin was mixed with a primary amine (R17-NH2) in [DICHLOROETHANE] (DCE), triethylorthoformate (TEOF), and DMF (containing [1%] acetic acid) in a 1: 1: 1 ratio. After shaken overnight, sodium triacetoxyborohydride (20 eq. ) dissolved in DMF was added (Abdel-Magid, A. F. , et al., Tetrahedron Lett, 3 1: 5595-5598 (1990) ). After the mixture was shaken at room temperature overnight, the resin was filtered and washed with DMF (3 x 5 mL), [MEOH] [(3 X 5] mL), DMF [(3 X 5] mL), [MEOH] [(3 X 5] mL), and [CH2CL2] [(3 X 5] mL). The resin was washed twice with 5 mL DMF containing [1%] Hunig's base. To the filtered resin was added a mixture of 4-fluoro-3-nitrobenzoic acid (FNBA, 10 eq. ) and diisopropylcarbodiimide (DIC, 5 eq. ) in 2: 1 DMF : DCM. After shaking at room temperature overnight, the resin was filtered and washed with DMF (3 x 5 mL) and [CH2C12] (3 x 5 mL). [73] The resin was shaken with a primary amine [(R2-NH2)] in DMF for 8 hrs, filtered, and washed with DMF (6 x 5 mL), [MEOH] [(3 X 5] mL), and CH2C12 (3 x 5 mL). The aryl nitro group was reduced by the addition of tin (II) chloride dihydrate (20 eq. , >2 M) and N-methyl morpholine (NMM, 20 eq. ) in N-methyl pyrrolidinone (NMP). After shaken at room temperature overnight, the resin was filtered and washed with NMP (3 x 5 mL), [MEOH] (3 x 5 mL), and [CH2CI2 (3 X 5] mL). The resulting resin was shaken at room temperature with cyanogen bromide (5 eq. ) overnight, filtered, and washed with CH2Cl2 (3 x 5 mL), [MEOH] (3 x 5 mL), and CH2CI2 (3 x 5 mL). To produce a free amine, the resin was shaken for 30 min. in CHCl2 with the addition of sodium methoxide in methanol, filtered, and washed with CH2Cl2 [(4 X 5] mL). [[74]] In the final diversification step, the resin was heated at 500 C in DMF with a mono- substituted epoxide [[RLCH (-CH2O-)].] After shaking for 2 to 4 days the resin was filtered and washed with DMF (5 x 5 mL), [MEOH] [(3 X 5] mL), and CH2Cl2 (3 x 5 mL). T he resin-bound benzimidazole was cleaved from the solid-support by treatment with TFA: [CH2C12] (2: 3) for 1 hour at room temperature. |