The chemistry of pyrrolic compounds. LIV. The chemistry of rhodins, verdins and related compounds

1984 ◽  
Vol 37 (1) ◽  
pp. 143 ◽  
Author(s):  
PS Clezy ◽  
AH Mirza ◽  
BN Ravi ◽  
LV Thuc

Coprorhodin II trimethyl ester has been prepared and its chemical and spectroscopic properties examined. Autoxidation of coprorhodin yields coproverdin while reduction with sodium borohydride affords a secondary alcohol which readily dehydrates under aerobic conditions to furnish a benzo-chlorin. The chemistry of these derivatives of coprorhodin has been studied.

1977 ◽  
Vol 55 (15) ◽  
pp. 2856-2866 ◽  
Author(s):  
Ronald T. Coutts ◽  
Abdel-Monaem El-Hawari

1′,2′-Dihydro-3-methyl-1-phenylspiro[[2]pyrazoline-4,3′(4′H)-quinoline]-5-one (8q), the structurally related 1,3-diphenylspiro[pyrazolone-quinoline] 8r and numerous 2′-substituted derivatives of 8q and 8r are readily accessible from catalytic reduction of 3-methyl-1-phenyl- or 1,3-diphenyl-4-(2-nitrobenzyl)-2-pyrazolin-5-one (1a, 1b, respectively) in alcohols (with the incorporation of the alkylidene moiety) or by interaction of the corresponding 2-aminobenzyl precursors (3a, 3b) with appropriate aldehydes and ketones. All spiro compounds were characterized by mass, ir, and 1Hmr spectra. The products obtained by reducing the spiro compounds with sodium borohydride and with lithium aluminum hydride are described. Reduction of 1a and 1b with zinc and acetic acid gave 3-methyl-1-phenyl- and 1,3-diphenyl-1H-pyrazolo[3,4-b]quinoline (2a, 2b, respectively).


1968 ◽  
Vol 110 (4) ◽  
pp. 693-702 ◽  
Author(s):  
M Akhtar ◽  
P. T. Blosse ◽  
P. B. Dewhurst

1. Convenient methods for the preparation of tritiated 11-cis-retinol, 11-cis-retinal and rhodopsin are described. Irradiation of labelled rhodopsin in the presence of sodium borohydride resulted in the irreversible binding of the retinyl moiety to the active site. Degradative studies established that the retinyl moiety in this reduced derivative of rhodopsin was attached to the ∈-amino group of lysine. In connexion with this investigation the synthesis of a number of N-retinylidene- and N-retinyl-amino acids was achieved. Derivatives of lysine with the retinyl moiety attached either to the α-amino group or to the ∈-amino group were also synthesized and characterized. 2. It is suggested that the involvement of a charge-transfer interaction between the retinylidene chromophore and a suitable group −X or −X·H on the opsin best explains the spectroscopic properties of rhodopsin and other visual proteins.


1976 ◽  
Vol 29 (10) ◽  
pp. 2247 ◽  
Author(s):  
HJ Banks ◽  
DW Cameron ◽  
MJ Crossley ◽  
EL Samuel

5,7-Dihydroxy-2,3-dimethyl-l,4-naphthoquinone (5) and related compounds have been synthesized. The quinone affords an accessible substrate for studying an unusual reaction with nucleophiles, which involves attack at the 8-position, i.e. at the benzenoid ring. An unsuccessful approach to (5) has led to tri- and tetra-nitro derivatives of 2,3-dimethylnaphthalene. Reduction of the former and subsequent conversions have given aminonaphthoquinone and perimidinone derivatives.


1982 ◽  
Vol 35 (7) ◽  
pp. 1391 ◽  
Author(s):  
AJ Liepa

N,N-Dialkyl derivatives of 3-aminoisoquinoline have been prepared by reaction of nitriles with various arylacetic acid tertiary amides in the presence of phosphoryl chloride. The synthesis has been extended to include a benzoisoquinoline and annulated isoquinolines by the selection of appropriate amide and nitrile precursors.


1944 ◽  
Vol 22b (5) ◽  
pp. 140-153 ◽  
Author(s):  
R. Y. Stanier ◽  
Sybil B. Fratkin

Aerobacter aerogenes, Aerobacillus polymyxa, and Aeromonas hydrophila, representatives of the three genera characterized by a butanediol fermentation, can all oxidize 2,3-butanediol under aerobic conditions. The configuration of the 2,3-butanediol has considerable bearing on its decomposability: Aerobacter aerogenes is inactive on the l-isomer, but attacks both meso- and d-isomers; Aeromonas hydrophila attacks the meso-isomer but not the l- and probably not the d-isomer; Aerobacillus polymyxa can oxidize both l- and meso-2,3-butanediol, but the rate with the former is many times greater than with the latter. Aerobacter aerogenes oxidizes both 2,3-butanediol and acetoin to carbon dioxide and water, a large part of the substrate being simultaneously assimilated. The other two organisms oxidize 2,3-butanediol to acetoin, but can further oxidize the acetoin thus formed only very slowly, if at all. Both Aerobacter aerogenes and Aerobacillus polymyxa are unable to attack 1,3-butanediol, 2-methyl-1,2-propanediol and 1,2-ethancdiol. However they can oxidize 1,2-propanediol to acetol.


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