Provided are compounds of formula (1) and to pharmaceutical compositions. Compounds, compositions and methods are useful, provided for the treatment of Flaviviridae virus Infections, including Infections by hepatitis C.Claim 1: a compound of formula (1) or a pharmaceutically acceptable Salt of the compound, wherein: X is o, s or NR1； each R1 is independently H c1-4 alkyl, optionally substituted, optionally substituted alquenilo C2 or C2 - 4 - 4 alquinilo each R2 or optionally substituted； R3 is independently H c1-4 alkyl, optionally substituted,Alquenilo c2-4 optionally replaced, alquinilo c2-4 optionally replaced, halogen, a cyano, R1, C (o) C (o) or 2 OR1 (R1； R2 and R3) or, when taken together with the carbon to which both are United, they are - C (= o) -, - C (= o) - O - C (= NR1) - is o, s or n), or alquileno NR4 c1-2 optionally replacing Each independently Gone； n is 0, 1 or 2； each is independently R4 HC1-4 alkyl, optionally substituted, alquenilo c2-4 optionally replaced, alquinilo c2-4 optionally replaced, cyano, R7, C (o) C (o) or7, with 2 (R7), S (or S) 2r16 R16, (OR), S (or S) or 2or7 (2n) (R7) 2； R5 is optionally substituted arylalkyl C0 - 4, 4 heterociclilalquilo C0 - optionally replaced,Cicloalquilalquilo C0 - C1 or optionally substituted alkyl 4 - 8 optionally substituted arylalkyl where each C0 - 4 - 4 cicloalquilalquilo optionally substituted, optionally substituted alkyl C0 or C1 - 8 is replaced optionally substituted with one or several R6 each R6 independently； Nte Halo, CF3, or4, ch2or4 SR4, R16, S (or S), (OR) 2r16 (R1), n 2, nhcor1, NHC (OR) OR1, NHC (o) n (R1) 2NHC (NR1) R1, NHC (NR1) n (R1) 2, C (o) C (o) n R1 (R1) 2, co2r1, S (or S) 2or1, (2 or) 2N (R1), NHS (or 2or1), NHS (2r16 NHS (, OR) 2 OR) 2N (R1), P (o) (OR1) 2, P (o) (OR1) (N (R1) 2), P (o) (R7) (OR1), op (OR) (OR1) (OR) 2, op (OR1) (N (R1) 2), NHP (NHP) (OR1) 2 or (OR) (OR1) (N (R1) 2)； each R7 is H, alkyl, optionally substituted alquenilo 8 C1, C2 8 Optionally replaced, C2 8 alqu
