B-Bilenes

Other b-bilenes. Deoxophylloerythroetioporphyrin (190) has been synthesized from a 6-bilene (191) (68JA6877) a Z>-bilene (192) was also a fleeting intermediate in Woodward s synthesis of chlorophyll a (60AG651) (vide infra). 

There are two main approaches to the corrin system. One of them completes the macrocycle by ring closure between C-l and C-19. This is the main route and quite versatile. The first example was reported for the octadehydrocorrin synthesis.239 Biladienes-a,c were cyclized in the presence of metal salts and air to 1,19-frms-ODC complexes, and radical Yin and cationic 16m conrotatory mechanisms have been suggested. The cyclization is also induced by light (Scheme 85). Similarly 1-ethoxy-2,3-dihydro-19-methyl-b-bilene is cyclized to l-ethoxy-19-methyl-7,8,12,13,17,18-HDC (M = Ni).239-249... 

Perhaps the most striking example of the b-bilene route in recent years has been its use in the synthesis of porphyrin-a (31) and its hexa-hydro analog. The key intermediate was the formyl porphyrin ester (28) (Scheme 5), which was converted to the corresponding acid chloride and used to acylate the magnesium... 

An interesting alternative synthesis of the benzoporphyrin (22) described above has also been accomplished by the b-bilene route, utilizing the condensation of a pyrromethane imine salt with a formyl pyrromethane containing a fused cyclohexanone ring. The use of the imine salt is reminiscent of Rapoport s synthesis of deoxophylloerythroaetio porphyrin described earlier, but in this... 

Positions can be numbered in two different manners but in most papers the meso positions have been designated with small italic letters in order to define the various unsaturations that can be introduced in these systems. Bilene-b, biladiene-a,c, bilatriene-a,b,c, for example, have been used to name the tetrapyrroles represented in Figs. 3b, 3c, 3d. 

Bihari, N., M. Fafandel, B. Hamer, and B. Kralj-Bilen. 2006. PAH content, toxicity and genotoxicity of coastal marine sediments from the Rovinj area, Northern Adriatic, Croatia. Sci. Total Environ. 366 602-611. 

Keles M, Yildirim R, Uyanik A, Turkmen M, Bilen Y, Aydinli B, Cetinkaya R, Polat KY. Neutropenia related to valacyclovir and valganciclovir in 2 renal transplant patients and treatment with granulocyte colony stimulating factor a case report. Exp Clin Transplant 2010 8(2) 181-3. 

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