Synthesis of Hetero Atom Modified Pyrromethenones

Abstract

A series of six heteroaromatic compounds, ethyl-/methyland dimethylfuranones, thiophenones, and cyclopentenones, was synthesized and condensed with a methyl methylpropionate substituted pyrrole, yielding the "right" half of openchain tetrapyrroles. These compounds serve as light-inducible chromophores in the plant photoreceptor phytochrome. Three-dimensional structure analysis of the 10-oxapyrromethen-1-one 25 revealed a planar conformation, similar to

Interactions Between Chromophore and Protein in Phytochrome Identified by Novel Oxa‐, Thia‐ and Carba‐Chromophores

“…A recently reported synthetic approach yielded six pyrryl‐furanones, ‐thiophenones and ‐cyclopentenones ( 10 – 15 , Fig. 2) (5) which represent the “right halves” of the convergent bilin synthesis, introduced by Gossauer et al. (7).…”

“…NMR: Spectra were recorded on Bruker ARX 250, DRX 400 or DRX 500 spectrometers in the solvents indicated; chemical shifts (d) are given in ppm relative to TMS, coupling constants (J) in Hz. The solvent signals were used as references and the chemical shifts were converted to the TMS scale (CDCl 3 : d C = 77.0 ppm; residual CHCl 3 in CDCl 3 : d H = 7.24 ppm; pyridine-d 5 : d C = 123.5 ppm; residual pyridine in pyridine-d 5 Although the nomination of the aldehydes 16-21 correlates with the IUPAC rules, for prudential reasons, the assignment of the hydrogen and carbon atoms in the case of NMR-analysis follows the Kekulef ormula displayed in Fig. 2.…”

“…m.p. 129°C; 1 H NMR (400 MHz, CDCl 3 ) d = 1.13 (t, 3 J = 7.59 Hz, 3H, 9 2 -CH 3 ), 2.11 (s, 3H, 4 1 -CH 3 ), 2.13 (s, 3H, 8 1 -CH 3 ), 2.39 (q, 3 J = 7.47 Hz, 3H, 9 1 -CH 2 ), 2.56 (t, 3 J = 7.63 Hz, 2H, 3 2 -CH 2 ), 3.03 (t, 3 J = 7.63 Hz, 2H, 3 1 -CH 2 ), 3.64 (s, 3H, CO 2 CH 3 ), 5.89 (s, 1H, 6-CH), 9.69 (s, 1H, CHO), 9.75 (br s, 1H, NH); 13 C NMR (101 MHz, 1 H ⁄ 13 C-COSY, CDCl 3 ) d = 8.75 (C-8 1 ), 9.67 (C-4 1 ), 12.73 (C-9 2 ), 17.36 (C-9 1 ), 19.11 (C-3 1 ), 35.25 (C-3 2 ), 51.75 (CO 2 CH 3 ), 95.07 (C-6), 123.35 (C-3), 129.72, 130.53, 130.68, 132.02 (C-2, -4, -5, -9), 146.54 (C-8), 148.46 (C-7), 169.07 (C-10), 172.78 (CO 2 CH 3 ), 177.47 (CHO); IR (KBr):m = 3439, 3070, 2965, 2928, 2852, 1759, 1734, 1637, 1444, 1384, 1213, 1164, 1100, 1008, 941, 574 (2), 272 (34), 271 (11), 270 (7), 260 (7), 243 (5), 230 (13), 228 (6), 217 (2), 203 (3), 186 (3), 176 (3), 162 (3), 158 (2), 146 (2), 136 (2), 134 (3), 119 (2), 118 (4), 117 (2), 107 (2), 106 (3), 104 (3), 91 (4), 79 (2), 77 (4), 67 (2), 65 (2), 53 (2), 41 (2) .53 (C-7 1 , -13 1 ), 10.12 (C-3 1 , -17 1 ), 12.41 (C-2 2 , -18 2 ), 17.10 (C-2 1 , -18 1 ), 19.63 (C-8 1 , -12 1 ), 34.90 (C-8 2 , -12 2 ), 51.45 (CO 2 CH 3 ), 98.71 (C-5, -15), 116.14 (C-10), 128.04 (C-7, -13), 137.97 (C-9, -11), 140.76 (C-6), 146.98 (C-3, -17), 148.24 (C-4,-16), 150.21 (C-14), 169.43 (C-1, -19), 172.83 (CO 2 CH 3 ); IR (KBr):m = 3448, 2930, 2874, 1757, 1743, 1640, 1594, 1458, 1437, 1385, 1357, 1260, 1236, 1170, 1097, 1057, 1014, 950, 906, 883, 801, 775, 736, 705, 673 (4), 469 (33), 392 (5), 316 (10), 242 (8) and 180 (3) 8.97 (C-9 1 ), 9.89 (C-4 1 ), 19.12 (C-3 1 ), 35.26 (C-3 2 ), 51.71 (CO 2 CH 3 ), 94.97 (C-6), 123.34 (C-3), 124.27, 126.79, 130.56, 132.41 (C-2, -4, -5, -9), 147.06 (C-8), 148.50 (C-7), 169.17 (C-10), 172.78 (CO 2 CH 3 ), 177.32 (CHO); IR (KBr):m ¼ 3441, 3064,2921,2854,1767,1730,1633,…”

“…This long-wavelength band usually consists of two closely lying absorption bands with one or the other being of slightly higher intensity. The long-wavelength absorbance maxima of the six novel ''PCB-analogs'' 4-9, together with those of PCB (2) and 17,18dimethyl PCB (3) (10) can be arranged into two groups: The carba-and the oxa-derivatives 4-7 showed relatively blueshifted absorption maxima of 606 and 608 nm (9,8), and of 611 and 613 nm (4,5), whereas the thia-(6, 7) and aza-derivatives PCB (2) and 17,18-dimethyl PCB (3) show absorption maxima with a redshift of 20 and more nm compared with the former ones: 629, 630 nm for 7 and 6, respectively, and 627 and 630 nm for PCB (2) itself and for 17,18-dimethyl PCB (3) (see Table 1).…”

“…We thus proposed that it might be the pyrrole nitrogen atom itself and the attached proton that play an important role for the P fr -stability. Based on a recent synthetic approach (5), we here present the six novel phytochrome chromophores 4-9 which instead of the photoisomerizing pyrrole ring D carry a furanone, a thiophenone, or a cyclopentenone ring, in each case substituted with either 18-ethyl-17-methyl or 17,18dimethyl substituents (Fig. 1).…”