Method of modulating ribonucleotide reductase

A pharmaceutical composition comprising a ribonucleotide reductase allosteric modulator (RRAmod), the RRAmod inhibiting cell growth when administered to a neoplastic cell, wherein the RRAmod includes a small molecule having the formula:

• wherein each of R1 to R20, R46 to R63 can be independently selected from the group consisting of hydrogen, C1-C24 alkyl, C2-C24 alkenyl, C2-C24 alkynyl, C3-C20 aryl, C6-C24 alkaryl, C6-C24 aralkyl, halo, silyl, hydroxyl, sulfhydryl, C1-C24 alkoxy, C2-C24 alkenyloxy, C2-C24 alkynyloxy, C5-C20 aryloxy, acyl (including C2-C24 alkylcarbonyl (—CO-alkyl) and C6-C20 arylcarbonyl (—CO-aryl)), acyloxy (—O-acyl), C2-C24 alkoxycarbonyl (—(CO)—O-alkyl), C6-C20 aryloxycarbonyl (—(CO)—O-aryl), C2-C24 alkylcarbonato (—O—(CO)—O-alkyl), C6-C20 arylcarbonato (—O—(CO)—O-aryl), carboxy (—COOH), carboxylato (—COO−), carbamoyl (—(CO)—NH2), C1-C24 alkyl-carbamoyl (—(CO)—NH(C1-C24 alkyl)), arylcarbamoyl (—(CO)—NH-aryl), thiocarbamoyl (—(CS)—NH2), carbamide (—NH—(CO)—NH2), cyano(—CN), isocyano (—N+C−), cyanato (—O—CN), isocyanato (—O—N+═C−), isothiocyanato (—S—CN), azido (—N═N+═N−), formyl (—(CO)—H), thioformyl (—(CS)—H), amino (—NH2), C1-C24 alkyl amino, C5-C20 aryl amino, C2-C24 alkylamido (—NH—(CO)-alkyl), C6-C20 arylamido (—NH—(CO)-aryl), imino (—CR═NH where R is hydrogen, C1-C24 alkyl, C5-C20 aryl, C6-C24 alkaryl, C6-C24 aralkyl, etc.), alkylimino (—CR═N(alkyl), where R=hydrogen, alkyl, aryl, alkaryl, aralkyl, etc.), arylimino (—CR═N(aryl), where R=hydrogen, alkyl, aryl, alkaryl, etc.), nitro (—NO2), nitroso (—NO), sulfo (—SO2—OH), sulfonato (—SO2—O−), C1-C24 alkylsulfanyl (—S-alkyl;
• also termed “alkylthio”), arylsulfanyl (—S-aryl;
• also termed “arylthio”), C1-C24 alkylsulfinyl (—(SO)-alkyl), C5-C20 arylsulfinyl (—(SO)-aryl), C1-C24 alkylsulfonyl (—SO2-alkyl), C5-C20 arylsulfonyl (—SO2-aryl), phosphono (—P(O)(OH)2), phosphonato (—P(O)(O−)2), phosphinato (—P(O)(O−)), phospho (—PO2), phosphino (—PH2), combinations thereof, and wherein adjacent R groups may be linked to form a cyclic or polycyclic ring, wherein the cyclic ring is aromatic, alicyclic, heteroaromatic, or heterocyclic;
• X1 is a C1-C24 alkyl, C2-C24 alkenyl, C2-C24 alkynyl;
• Y1 is a C1-C24 alkyl, C2-C24 alkenyl, C2-C24 alkynyl;
• R45 is hydrogen, a C1-C24 alkyl, C2-C24 alkenyl, C2-C24 alkynyl, an amino (—NH2), —(C1-C24 alkyl)-amino, and combinations thereof;
• and a pharmaceutically acceptable salt thereof.