Caged amino acid derivatives bearing photolabile protective groups

A method for producing a free amino acid or derivative thereof comprising the step of UV irradiating a compound represented by structural Formulae (I), (II), (IV), (V), (VI) or (VII):

• wherein R1 and R2, which may be the same or different, are each selected from the group consisting of H, Li, Na, K, Cs, an alkyl group having from 1 to 5 carbon atoms, NH4, and —CH2O2C—R1a, wherein R1a is an alkyl group having from 1 to 5 carbon atoms additionally, R2 is selected from the group consisting of 3,4-dihydro-4-oxo-1,2,3-benzotriazin-3-yl, 2-nitrophenyl, 4-nitrophenyl, pentachlorophenyl, pentafluorophenyl, and N-succinimidyl;
• wherein R3 is selected from the group consisting of H, an alkyl group having from 1 to 5 carbon atoms, CH3—S—(CH2)2—, benzyl, and —(CH2)n—(CO)—Y, wherein n is an integer of from 1 to 5 and Y is OR3a or NR3bR3c, wherein R3a, R3b and R3c, which may be the same or different, are each selected from the group consisting of H and an alkyl group having from 1 to 5 carbon atoms, and R3a may additionally be selected from the group consisting of Li, Na, K and Cs;
• wherein R4 and R5, which may be the same or different, are each selected from the group consisting of H, an alkyl group having from 1 to 5 carbon atoms, F, Cl, Br, CN, NO2, CO2R4a, OR4a, wherein R4a is selected from the group consisting of H, Li, Na, K, Cs, an alkyl group having from 1 to 5 carbon atoms, NH4, and —CH2O2R4b, wherein R4b is an alkyl group having from 1 to 5 carbon atoms;
• and wherein optionally, R4 and R5 together from a methylenedioxy (O—CH2—O) linkage;
• wherein R6 is selected from the group consisting of H, t-butyloxycarbonyl (Boc), benzyloxycarbonyl (Cbz), 9-fluorenylmethyloxycarbonyl (Fmoc), and a group represented by structural Formula (III);
• wherein R7 is selected from the group consisting of H, Li, Na, K, Cs, an alkyl group having from 1 to 5 carbon atoms, NH4, 3,4-dihydro-4-oxo-1,2,3-benzotriazin-3-yl, 2-nitrophenyl, 4-nitrophenyl, pentachlorophenyl, pentafluorophenyl, and N-succinimidyl, and —CH2O2C—R7a, wherein R7a is an alkyl group having from 1 to 5 carbon atoms;
• wherein R8 is selected from the group consisting of —(CH2-p(CH3)p)—Y—R8a, —(CH2-p(CH3)p)—C6H4—Y—R8a, wherein p is 0, 1, or 2, Y is O or S, wherein R8a is a group represented by structural Formula (III), and —(CH2)q—Z, wherein q is 3 or 4, and Z is —NH—R8b or —NH—C(═NH)—NH—R8b, wherein R8b is a group represented by structural Formula (III);
• wherein R9 is selected from the group consisting of H, Li, Na, K, Cs, an alkyl group having from 1 to 5 carbon atoms, NH4, and —CH2O2C—R9a, wherein R9a is an alkyl group having from 1 to 5 carbon atoms;
• wherein R10 and R11, which may be the same or different, are each selected from the group consisting of H, an alkyl group having 1 to 5 carbon atoms, F, Cl, Br, CN, NO2, CO2R10a, and OR10a, wherein R10a is selected from the group consisting of H, Li, Na, K, Cs, an alkyl group having from 1 to 5 carbon atoms, NH4, and —CH2O2C—R10b, wherein R10b is an alkyl group having from 1 to 5 carbon atoms;
• and wherein optionally, R10 and R11 together from a methylenedioxy (O—CH2—O) linkage;
• wherein R12 is selected from the group consisting of H, t-butyloxycarbonyl (Boc), benzyloxycarbonyl (Cbz), 9-fluorenylmethyloxycarbonyl (Fmoc), and a group represented by structural Formula (III);
• wherein R13 is selected from the group consisting of H, Li, Na, K, Cs and an alkyl group having from 1 to 5 carbon atoms, NH4, 3,4-dihydro-4-oxo-1,2,3-benzotriazin-3-yl, 2-nitrophenyl, 4-nitrophenyl, pentachlorophenyl, pentafluorophenyl, and N-succinimidyl, and —CH2O2C—R13a, wherein R13a is an alkyl group having from 1 to 5 carbon atoms;
• and
• wherein R14 is a group represented by structural Formula (III), and recovering said free amino acid or derivative thereof.