Abstract: A compound of the formula II wherein one of R1 and R2 is halo and the other is H or halo; R3 is C1-C4 straight or branched chain, optionally fluorinated, alkyl; R4 is H; or R3 together with R4 and the adjoining backbone carbon defines: a spiro-C5-C7 cycloalkyl, optionally substituted with 1 to 3 substituents selected from halo, hydroxyl, C1-C4 alkyl or C1-C4 haloalkyl; or optionally bridged with a methylene group; or a C4-C6 saturated heterocycle having a hetero atom selected from O, NRa, S, S(?O)2; where Ra is H, C1-C4 alkyl or CH3C(?O); R5 is independently selected from H or methyl; E is —C(?O)—, —S(?O)m—, —NR5S(?O)m—, —NR5C(?O)—, —OC(?O)—, R6 is a stable, optionally substituted, monocyclic or bicyclic, carbocycle or hetorocycle; m is independently 0, 1 or 2; are inhibitors of cathepsin K and useful in the treatment or prophylaxis of osteoporosis.

Abstract: A compound of the formula II wherein one of R1 and R2 is halo and the other is H or halo; R3 is C1-C4 straight or branched chain, optionally fluorinated, alkyl; R4 is H; or R3 together with R4 and the adjoining backbone carbon defines: a spiro-C5-C7 cycloalkyl, optionally substituted with 1 to 3 substituents selected from halo, hydroxyl, C1-C4 alkyl or C1-C4 haloalkyl; or optionally bridged with a methylene group; or a C4-C6 saturated heterocycle having a hetero atom selected from O, NRa, S, S(?O)2; where Ra is H, C1-C4 alkyl or CH3C(?O); R5 is independently selected from H or methyl; E is —C(?O)—, —S(?O)m—, —NR5S(?O)m—, —NR5C(?O)—, —OC(?O)—, R6 is a stable, optionally substituted, monocyclic or bicyclic, carbocycle or heterocycle; m is independently 0,1 or 2; are inhibitors of cathepsin K and useful in the treatment or prophylaxis of osteoporosis.

Abstract: A compound of the formula (II) wherein one of R1 and R2 is halo and the other is H or halo; R3 is —C1-C5 straight or branched chain, optionally fluorinated, alkyl or —CH2CR5C3-C4-Cycloalkyl; R4 is H; R5 is H, C1-C2 alkyl, C1-C2 haloalkyl, hydroxyl, OC1-C2alkyl, fluoro; R6 is a stable, optionally substituted, monocyclic or bicyclic, carbocycle or heterocycle wherein the or each ring has 4, 5 or 6 ring atoms and 0 to 3 hetero atoms selected from S, O and N; Rb is haloalkyl; Rc is H or C1-C4 alkyl; and pharmaceutically acceptable salts, hydrates or N-oxides thereof have utility in the treatment of disorders characterised by inappropriate expression or activation of cathepsin K, such as osteoporosis, osteoarthritis, rheumatoid arthritis or bone metastases.

Abstract: A compound of the formula II wherein one of R1 and R2 is halo and the other is H or halo; R3 is C1-C4 straight or branched chain, optionally fluorinated, alkyl; R4 is H; or R3 together with R4 and the adjoining backbone carbon defines: a spiro-C5-C7 cycloalkyl, optionally substituted with 1 to 3 substituents selected from halo, hydroxyl, C1-C4 alkyl or C1-C4 haloalkyl; or optionally bridged with a methylene group; or a C4-C6 saturated heterocycle having a hetero atom selected from O, NRa, S, S(?O)2; where Ra is H, C1-C4 alkyl or CH3C(?O); R5 is independently selected from H or methyl; E is —C(?O)—, —S(?O)m—, —NR5S(?O)m—, —NR5C(?O)—, —OC(?O)—, R6 is a stable, optionally substituted, monocyclic or bicyclic, carbocycle or heterocycle; m is independently 0,1 or 2; are inhibitors of cathepsin K and useful in the treatment or prophylaxis of osteoporosis.