Reactivities of Amino Acids towards Photoalkylation with Benzophenone
FULL PAPER
[3]
20
´
Y. Nakatani, M. Yamamoto, Y. Diyizou, W. Warnock, V. Dolle,
γ-Coupling Product 18: White solid; M.p. 116°C; [α]D ϭ ϩ13.0
W. Hahn, A. Milon, G. Ourisson, Chem. Eur. J. 1996, 2,
129Ϫ138.
(c ϭ 1.0 in MeOH). Ϫ 1H NMR (200 MHz, CDCl3): δ ϭ
[4] [4a]
7.79Ϫ7.51 (m, 4 H, aryl-H), 7.24-6.86 (m, 6 H, aryl-H), 6.06 [d, br,
3J(H,H) ϭ 7.4 Hz, 1 H, NH], 5.08 [ddd, 3J(H,H) ϭ 8.3 Hz, 7.4
Hz, 5.4 Hz, 1 H, NCH], 3.91 [dd, 3J(H,H) ϭ 10.4 Hz, 2.1 Hz, 1
H, SCH], 3.49 (s, 1 H, OH), 3.29 (s, 3 H, CO2CH3), 2.29 [ddd,
2J(H,H) ϭ 14.8 Hz, 3J(H,H) ϭ 8.3 Hz, 2.1 Hz, 1 H, methylene H],
C. M. Gupta, C. E. Costello, H. G. Khorana, Proc; Natl.
[4b]
Acad. Sci, USA 1979, 76, 3139Ϫ3143. Ϫ
M. F. Czarniecki,
[4c]
R. Breslow, J. Am. Chem. Soc. 1979, 101, 3675Ϫ3676. Ϫ
A.
H. Ross, R. Radhakrishnan, R. J. Robson, H. G. Khorana, J.
Biol. Chem. 1982, 257, 4152Ϫ4161.
[5]
[6]
G. Dorman, G. D. Prestwich, Biochemistry 1994, 33,
5661Ϫ5673.
1.74 [ddd, J(H,H) ϭ 14.8 Hz, 3J(H,H) ϭ 10.4 Hz, 5.4 Hz, 1 H,
2
F. Kotzyba, I. Kapfer, M. Goeldner, Angew. Chem. Int. Ed.
Engl. 1995, 34, 1296Ϫ1312.
methylene H], 1.49 (s, 3 H, COCH3 or SCH3), 1.44 (s, 3 H, COCH3
or SCH3). Ϫ 13C NMR (50 MHz, CDCl3): δ ϭ 172.7, 169.9, 145.9,
144.4, 128.4, 128.2, 127.1, 126.0, 125.8, 80.7, 55.1, 52.4, 51.5, 34.8,
23.1, 17.1. Ϫ IR (KBr): ν˜ ϭ 3494, 3239, 3059, 2950, 2920, 2846,
1731, 1635, 1600, 1560, 1493, 1448, 1020, 751, 706 cmϪ1. Ϫ UV
(MeOH): λmax ϭ 258, 222 nm. Ϫ MS (FAB): m/z (%): 388 (3)
[MϩH]ϩ, 370 (100), 311, 251 (34), 204 (85), 183 (55). Ϫ C21H26NO4
calcd 388.1583; found 388.1577 (MS).
[7] [7a]
R. E. Galardy, L. C. Craig, M. P. Printz, Nature New Biol.
[7b]
1973, 242, 127Ϫ128. Ϫ
R. E. Galardy, L. C. Craig, J. D.
Jamieson, M. P. Printz, J. Biol. Chem. 1974, 249, 3510Ϫ3518.
L. Stryer, Biochemistry , 3rd ed., Freeman, New York, 1988,
pp. 302Ϫ303.
[8]
[9]
[9a] P. Wagner, Bong-Ser Park, Organic Photochemistry 1991, 11,
[9b]
[9c]
227Ϫ366. Ϫ
Organic Photochemistry 1991, 11, 230. Ϫ
[9d]
Organic Photochemistry 1991, 11, 242. Ϫ
Acc. Chem. Res., 1977, 10, 173Ϫ179.
M. A. Winnik,
[10] [10a]
S-Methyl Coupling Product 19: Clear, colourless, highly viscous
J. F. Biernat, Roszniki Chemii, Ann. Soc. Chim. Polonorum
[10b]
20
oil; [α]D ϭ Ϫ5.6 (c ϭ 1.0 in MeOH). Ϫ 1H NMR (200 MHz,
1971, 45, 2081Ϫ2087. Ϫ
Soc., Chem. Commun. 1977, 238Ϫ239.
N. Obata, K. Niimura, J. Chem.
3
CDCl3): δ ϭ 7.50Ϫ7.18 (m, 10 H, aryl-H), 6.03 [d, br, J(H,H) ϭ
[11] [11a]
J. N. Pitts, Jr., H. W. Johnson, T. Kuwana, J. Phys. Chem.
[11b]
7.4 Hz, 1 H, NH], 4.69 (m, 1 H, NCH), 3.79 (s, 1 H, OH), 3.71 (s,
3 H, CO2CH3), 3.42 [s, 2 H, SCH2C(OH)Ph2], 2.48 (m, 2 H,
SCH2CH2), 2.18Ϫ1.80 (m, 2 H, SCH2CH2), 1.99 (s, 3 H, COCH3).
1962, 66, 2456Ϫ2461. Ϫ
P. J. Wagner, R. J. Truman, J. C.
Schiano, J. Am. Chem. Soc. 1985, 107, 7093Ϫ7097.
H. G. Viehe, Z. Janousek, R. Mereny, L. Stella, Acc. Chem. Res.
1985, 18, 148Ϫ154.
[12]
[13]
[14]
[15]
Ϫ
13C NMR (50 MHz, CDCl3): δ ϭ 172.7, 170.2, 145.7, 128.6,
N.J. Turro, Molecular Photochemistry, University Science
Books, Mill Valley, 1991, pp. 372 Ϫ 375.
128.3, 127.3, 126.2, 77.5, 52.6, 51.4, 46.2, 32.6, 30.1, 23.1. Ϫ IR
(KBr): ν ϭ 3304, 3060, 3032, 2952, 2848, 1740, 1669, 1599, 1544,
˜
U. Schöllkopf, U. Groth, W. Hartwig, Liebigs Ann. Chem.
1981, 2407Ϫ2418.
1448, 1374, 1220, 1171 cmϪ1. Ϫ UV (MeOH): λmax ϭ 253, 229 nm.
Ϫ MS (FAB): m/z (%): 388 (5) [MϩH]ϩ, 370 (100), 251 (21), 205
(28), 190 (32), 183 (53), 158 (92). Ϫ C21H25NO4 (387.5): calcd C
65.09, H 6.50, N 3.61; found C 65.43, H 6.55, N 3.53.
J. Brunner, Annu. Rev. Biochem. 1993, 62, 483Ϫ514.
[16] [16a]
D. P. Curran, N. A. Porter, B. Giese, Stereochemistry of
[16b]
Radical Reactions, VCH, Weinheim, 1996, p. 5. Ϫ
pp. 147Ϫ164.
ibid.
[17] [17a]
[17b]
P. Metz, Tetrahedron 1993, 49, 6367Ϫ6374. Ϫ
S. Shi-
Chemoselectivity: The Pyrex walls of the lampЈs cooling jacket
are supposed to filter off wavelengths below 300 nm, which would
be destructive to amino acids.[29] Nevertheless, blank experiments
were performed irradiating protected amino acids without benzo-
phenone under standard conditions. The 1H-NMR spectra after
irradiation were identical with those of original probes, except for
cystine in pyridine/H2O, which was found to be monomerized to
cysteine in 4% yield.
mada, Y. Hashimoto, T. Nagashima, M. Hasegawa, K. Saigo,
[17c]
Tetrahedron 1993, 49, 1589Ϫ1604. Ϫ
A. R. Battersby, M.
G. Baker, H. A. Broadbent, C. J. R. Fookes, F. J. Leeper, J.
[17d]
Chem. Soc. Perkin Trans I 1987, 2027Ϫ2048. Ϫ
M. J.
Kurth, O. H. W. Decker J. Org. Chem. 1986, 51, 1377Ϫ1383. Ϫ
[17e]
A. W. Hanson, A. W. McCulloch, A. G. McInnes, Can. J.
Chem. 1981, 59, 288Ϫ301.
[18]
D. N. Kirk, Tetrahedron , 1986, 42, 777Ϫ818.
[19] [19a]
W. Klyne, P. M. Scopes in Optical Rotatory Dispersion and
Circular Dichroism in Organic Chemistry (Ed.: G. Snatzke),
[19b]
Heyden, London, 1967, pp. 193Ϫ207. Ϫ
J.P. Jennings, W.
Ten tubes with the derivatized amino acids of Table 2 (1.0 mol/
l) and benzophenone 2 (1.0 mol/l) in acetonitrile were irradiated at
the same time following the general procedure (20 h, T ϭ 32°C).
In the same way, the 20 amino acid compounds listed in table 3
(0.5mol/l) with benzophenone (2) (0.5 mol/l) in pyridine/H2O, 4:1,
were processed (20 h, T ϭ 37°C). Solvents were evaporated in vac-
[19c]
Klyne, P.M. Scopes, Proc. Chem. Soc., 1964, 412Ϫ413. Ϫ
T. Okuda, S. Harigaya, A. Kiyomoto, Chem. Pharm. Bull. Ja-
pan, 1964, 12, 504Ϫ506.
[20] [20a] D. Elad, J. Sinnreich, J. Chem. Soc., Chem. Commun. 1965,
[20b]
19, 471Ϫ472. Ϫ
D. Elad, J. Sperling, J. Chem. Soc. (C)
1969, 1579Ϫ1585. Ϫ [20c] D. Elad, J. Sperling, J. Am. Chem. Soc
[20d]
1971, 93, 967Ϫ971. Ϫ
J. Sperling, D. Elad, J. Am. Chem.
[20e]
1
Soc. 1971, 93, 967Ϫ971. Ϫ
M. Schwarberg, J. Sperling, D.
uum and the crude reaction mixtures were analyzed by H NMR
Elad, J. Am. Chem. Soc. 1973, 95, 6418Ϫ6426.
spectroscopy. The percentages of converted amino acids were estab-
lished by comparing the integration of the eductЈs methyl ester sin-
glet to that of the sum of new singlets appearing at δ ϭ 4.0Ϫ3.3.
In this way, all products were accounted for that conserved a
methyl ester function, i.e. coupling products and amino acid di-
mers, but the γ-lactones were not detected. This might become a
problem as almost quantitative cyclization to the γ-lactone 16 oc-
cured with AcPheOMe in pyridine/H2O. Favourable signal separ-
ation allowed in the cases of AcHisOMe,·HOAc, and AcTrpOMe
to integrate acetyl signals and thus to include possible γ-lactones.
The differences with the amino acid consumption calculated on the
basis of methyl ester signals were below 2%. This is the margin of
error for the calculated conversions.
[21] [21a]
C. J. Easton in Advances in Detailed Reaction Mechanisms,
Vol. 1 (Ed.: J. M. Coxon), JAI Press, Greenwich, 1991, pp.
[21b]
83Ϫ126. Ϫ
ibid., p. 96.
[22]
[23]
S. G. Cohen, A. Parola, G. H. Parsons, Jr., Chem. Rev. 1973,
73, 141Ϫ146.
T. Shono, Y. Matsumura, K. Tsubata, Y. Sugihara, S. Yamane,
T. Kanazawa, T. Aoki, J. Am. Chem. Soc. 1982, 104,
6697Ϫ6703.
[24]
[25]
H. Poisel, U. Schmidt, Chem. Ber. 1975, 108, 2917Ϫ2922.
L. J. Liotta, R. A. Gibbs, S. D. Taylor, P. A. Benkovic, S. J.
Benkovic, J. Am. Chem. Soc. 1995, 117, 4729Ϫ4741.
A. Conchillo, F. Camps, A. Messeguer, J. Org. Chem. 1990,
55, 1728Ϫ1735.
[26]
[27]
H. J. F. Angus, J. McDonald Blair, D. Bryce-Smith, J. Chem.
Soc. 1960, 2003Ϫ2007.
[28] [28a]
J. Leimner, P. Weyerstahl, Chem. Ber. 1982, 115,
3697Ϫ3705. Ϫ [28b] J.-C. Gramain, R. Remuson, Y. Troin, Tetra-
[28c]
hedron 1979, 35, 753Ϫ758. Ϫ
Soc. Chim. Fr. 1968, 2470Ϫ2475.
P. Depover, R. Devis, Bull.
[1]
For a recent example, see E. M. Landau, J. P. Rosenbusch, Proc.
[29]
Natl. Acad. Sci. USA, 1996, 93, 14532Ϫ14535.
K. M. Schaich, CRC Crit. Rev. Food Science and Nutrition
[2]
M. Tomita, H. Furthmayr, V. T. Marchesi, Biochemistry 1978,
17, 4756Ϫ4770.
1980, 13, 131Ϫ159.
[97345]
Eur. J. Org. Chem. 1998, 243Ϫ251
251