Abstract: A pharmaceutical composition comprising a compound of formula (I) wherein X is an electron withdrawing group, Y1 is hydrogen, alkyl, alkenyl, alkynyl, aryl, heterocyclyl, —SO2R4, —CO2R4, —CONHR4 or —COR4, and each of R1, R2 and R4, which may be the same or different, is hydrogen, alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl or heterocyclyl, or a compound of formula (II) wherein each of Y2 and Y3, which may be the same or different, is hydrogen, alkyl, alkenyl, alkynyl, aryl, heterocyclyl, —SO2R9, —CO2R9, —CONHR9 or —COR9, Z is hydrogen, alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl, heterocyclyl, —CH?C(NHR10)CH((CH2)m CO2R11)(C?O)CH3 or —CH2(C?O)CH((CH2)mCO2R11)(C?O)CH3, R8 is —(CH2)nCO2R12, each of R5 to R7 and R9 to R12, which may be the same or different, is hydrogen, alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl or heterocyclyl, and each of m and n, which may be the same or different, is 1 to 6 or a compound of formula (III) wherein each of Y4 to Y6, which may be the same or

Abstract: A pharmaceutical composition comprising a compound of formula (I) wherein X is an electron withdrawing group, Y1 is hydrogen, alkyl, alkenyl, alkynyl, aryl, heterocyclyl, —SO2R4, —CO2R4, —CONHR4 or —COR4, and each of R1, R2 and R4, which may be the same or different, is hydrogen, alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl or heterocyclyl, or a compound of formula (II) wherein each of Y2 and Y3, which may be the same or different, is hydrogen, alkyl, alkenyl, alkynyl, aryl, heterocyclyl, —SO2R9, —CO2R9, —CONHR9 or —COR9, Z is hydrogen, alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl, heterocyclyl, —CH?C(NHR10)CH((CH2)mCO2R11)(C?O)CH3 or —CH2(C?O)CH((CH2)mCO2R11)(C?O)CH3, R8 is —(CH2)nCO2R12, each of R5 to R7 and R9 to R12, which may be the same or different, is hydrogen, alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl or heterocyclyl, and each of m and n, which may be the same or different, is 1 to 6 or a compound of formula (III) wherein each of Y4 to Y6, which may be the same or

Abstract: A pharmaceutical composition comprising a compound of formula (I) wherein X is an electron withdrawing group, Y1 is hydrogen, alkyl, alkenyl, alkynyl, aryl, heterocyclyl, —SO2R4, —CO2R4, —CONHR4 or —COR4, and each of R1, R2 and R4, which may be the same or different, is hydrogen, alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl or heterocyclyl, or a compound of formula (II) wherein each of Y2 and Y3, which may be the same or different, is hydrogen, alkyl, alkenyl, alkynyl, aryl, heterocyclyl, —SO2R9, —CO2R9, —CONHR9 or —COR9, Z is hydrogen, alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl, heterocyclyl, —CH═C(NHR10)CH((CH2)mCO2R11)(C═O)CH3 or —CH2(C═O)CH((CH2)mCO2R11)(C═O)CH3, R8 is —(CH2),CO2R12, each of R5 to R7 and R9 to R12, which may be the same or different, is hydrogen, alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl or heterocyclyl, and each of m and n, which may be the same or different, is 1 t