Derivatives of 1-amino-2-cyclopropylethylboronic acid

A compound of formula (I):

• or a pharmaceutically acceptable salt or boronic acid anhydride thereof, wherein:
• A is 0, 1, or 2;
• P is hydrogen or an amino-group-blocking moiety;
• each Ra2 independently is hydrogen, C1-6 aliphatic, C1-6 fluoroaliphatic, —(CH2)m—CH2—RB, —(CH2)m—CH2—NHC(═NR4)NH—Y, —(CH2)m—CH2—CON(R4)2, —(CH2)m—CH2—N(R4)CON(R4)2, —(CH2)m—CH(R6)N(R4)2, —(CH2)m—CH(R5)—OR5, or —(CH2)m—CH(R5)—SR5;
• each Y independently is hydrogen, —CN, —NO2, or —S(O)2—R10;
• each RB independently is a substituted or unsubstituted mono- or bicyclic ring system;
• each R4 independently is hydrogen or a substituted or unsubstituted aliphatic, aryl, heteroaryl, or heterocyclyl group;
• or two R4 on the same nitrogen atom, taken together with the nitrogen atom, form a substituted or unsubstituted 4- to 8-membered heterocyclyl ring having, in addition to the nitrogen atom, 0-2 ring heteroatoms independently selected from N, O, and S;
• each R5 independently is hydrogen or a substituted or unsubstituted aliphatic, aryl, heteroaryl, or heterocyclyl group;
• each R6 independently is a substituted or unsubstituted aliphatic, aryl, or heteroaryl group;
• each R10 independently is C1-6 aliphatic, C6-10 aryl, or —N(R4)2;
• m is 0, 1, or 2;
• and
• Z1 and Z2 are each independently hydroxy, alkoxy, aryloxy, or aralkoxy;
• or Z1 and Z2 together form a moiety derived from a boronic acid complexing agent.