Total Syntheses of (±)-Phycocyanobilin and Its Derivatives Bearing a Photoreactive Group at D-ring

Abstract

(±)-Phycocyanobilin and its derivatives bearing a photoreactive group at D-ring were first synthesized by the development of a new and convenient method for the preparation of A-ring, transesterification for propanoic acid side-chains of the pyrrole derivative common to B- and C-rings, and deprotection of allyl ester side-chains with a palladium catalyst to avoid migration of exocyclic olefin of A-ring.

In vitro assembly of phytochrome B apoprotein with synthetic analogs of the phytochrome chromophore

“…1) was achieved by bromination and subsequent acidic hydrolysis (24). Finally, tetrapyrrole structures using these Drings were constructed according to the described method (15). All bilins were stored as 2-mM stock solutions in dimethyl sulfoxide under nitrogen atmosphere at Ϫ80°C.…”

“…Gossauer and Hinze (14) reported total synthesis of the dimethyl ester derivatives of P⌽B and PCB, but they were unable to assemble these analogs with phytochrome apoprotein. After the efforts of a decade, we succeeded in synthesizing PCB, P⌽B, and various PCB analogs in free-acid forms by developing efficient methods for the preparation of each pyrrole ring (15)(16)(17)(18)(19)(20) and a method for coupling them (18,(21)(22)(23)(24) and palladium-catalyzed deprotection of the allyl propanoate side chains of B-and C-rings under mild conditions (15).…”

Structural requirement of bilin chromophore for the photosensory specificity of phytochromes A and B

“…Through chemical synthesis of P⌽B (17), phycocyanobilin (PCB) (18), and various analogs (19 -21), the structural determinants of the bilin precursor on reconstituted phytochrome can now be addressed. Photochromic properties of holophytochromes are inf luenced by the nature of the side chains of the bilin chromophores, if they are adducted with recombinant phytochrome apoproteins (19 -21).…”

“…R͞FR and FR͞R were generated by using a custom-built LED irradiation system, as previously reported (11 Bilin Preparation. PCB (18), P⌽B (17), and their analogs (21,29) were chemically synthesized, as reported. The bilins were stored as 2 mM stock solutions in dimethyl sulfoxide under nitrogen atmosphere at Ϫ80°C.…”

Syntheses of Biliverdin Derivatives Sterically Locked at the CD-Ring Components

“…The solvent was evaporated, and the blue residue was separated by thin layer chromatography (SiO 2 , hexane/CHCl 3 / MeOH = 7/4/0.5, v/v/v) to afford compound 2b in 87% yield (181 mg) as a blue solid. Mp 181-183 C (from CH 2 Cl 2 / hexane); IR (KBr) 3444,2925,1730,1686,1589,1456,1415,1274,1177,1098,960,916,833 (d,J ¼ 17:5 Hz,1H),5.87 (ddt,J ¼ 17:2,10.4,5.6 Hz,1H),5.89 (ddt,J ¼ 17:2,10.4,5.7 Hz,1H),6.07 (s,1H),6.28 (s,1H),6.64 (dd,J ¼ 17:5,10.8 Hz,1H),6.81 (s,1H). NH protons were not observed clearly.…”