Total synthesis of 8(S)-, 9(S)-, 11(S)-, and 12(S)-hydroxyeicosatetraenoic acids (HETE) methyl esters

1986 ◽  
Vol 51 (25) ◽  
pp. 4796-4802 ◽  
Author(s):  
George Just ◽  
Zhi Yuan Wang
Keyword(s):  
Total Synthesis ◽  
Methyl Esters ◽  
Hydroxyeicosatetraenoic Acids

Two new diphenyl ethers and a new depside from the lichen Micarea prasina Fr

1984 ◽  
Vol 37 (11) ◽  
pp. 2349 ◽  
Author(s):  
JA Elix ◽  
AJ Jones ◽  
LCBJ Lajide ◽  
PW James
Keyword(s):  
Total Synthesis ◽  
Methyl Esters ◽  
Sodium Hydride ◽  
Hydroxybenzoic Acid ◽  
Type Synthesis ◽  
Enol Ethers ◽  
Diphenyl Ethers ◽  
Key Steps ◽  
Methoxybenzoic Acid

Two new diphenyl ethers, 4-(2-carboxy-3-heptyl-5-methoxyphenoxy)-2-heptyl-6-hydroxybenzoic acid (micareic acid) (13), 4-(2-carboxy-3-heptyl-5-methoxyphenoxy)-2-heptyl-6-hydroxy-3-methoxybenzoic acid (methoxymicareic acid) (27) and a new depside, 4-(2-heptyl-6-hydroxy-4-methoxybenzoyloxy)- 2-heptyl-6-hydroxybenzoic acid (prasinic acid) (34) have been detected in chemical races of the lichen Micarea prasina Fr. and isolated and characterized as the corresponding methyl esters. The structure of the latter compounds has been confirmed by total synthesis. The key steps in the synthesis of the diphenyl ethers (14), (26) involved Ullmann-like condensation between the 3-chloro 2-enone (17) and the phenols (11), (31), and subsequent aromatization of the enol ethers (23) and (32). A biomimetic-type synthesis of methyl micareate (48) has also been achieved by treatment of the depside (33) with sodium hydride in dimethylformamide.

Macrocyclic intermediates in the biosynthesis of porphyrins

1976 ◽  
Vol 273 (924) ◽  
pp. 191-206 ◽  
Keyword(s):  
High Pressure ◽  
Acetic Acid ◽  
Total Synthesis ◽  
Methyl Esters ◽  
Protoporphyrin Ix ◽  
Acid Group ◽  
Spectroscopic Methods ◽  
Uroporphyrinogen Decarboxylase ◽  
Abnormal Metabolism ◽  
Chicken Erythrocytes

The hepta-, hexa- and penta-carboxylic porphyrins found in the faeces of rats poisoned with hexachlorobenzene have been separated by high-pressure liquid chromatography and characterized largely by spectroscopic methods. Their structures were confirmed by total synthesis, as part of a programme in which eleven of the fourteen hepta-, hexa- and penta-carboxylic porphyrins derived from uroporphyrin III have now been synthesized as their methyl esters. The four isomeric heptacarboxylic and three of the pentacarboxylic porphyrinogens have been incubated with haemolysates of chicken erythrocytes, and they are all converted into protoporphyrin IX but at different rates. On the basis of this and other evidence we conclude that the decarboxylation of uroporphyrinogen III to coproporphyrinogen III is a stepwise process taking place by a preferred pathway (both in normal and abnormal metabolism) ; the acetic acid groups are decarboxylated in a sequential clockwise fashion starting with that on the D ring and followed by those on the A, B and C rings. In the poisoned rats the uroporphyrinogen decarboxylase enzyme (or group of enzymes) is probably partially inhibited and the pentacarboxylic porphyrinogen with an acetic acid group on ring C accumulates. The latter is then transformed by a side pathway into dehydroisocoproporphyrinogen and thence into dehydroisocoproporphyrin and its congeners.

Total synthesis of chromomoric acid B and F methyl esters

Tetrahedron ◽  
1995 ◽  
Vol 51 (1) ◽  
pp. 173-180 ◽  
Author(s):  
Xin-Jie Chu ◽  
Hong Dong ◽  
Zhi-Yu Liu
Keyword(s):  
Total Synthesis ◽  
Methyl Esters

Ovarian hydroxyeicosatetraenoic acids compared with prostanoids and steroids during ovulation in rats

1991 ◽  
Vol 260 (2) ◽  
pp. E163-E169 ◽  
Author(s):  
L. L. Espey ◽  
N. Tanaka ◽  
R. F. Adams ◽  
H. Okamura
Keyword(s):  
Wistar Rats ◽  
Potent Inhibitor ◽  
Methyl Esters ◽  
Steroid Synthesis ◽  
Inflammatory Reactions ◽  
Acid Methyl ◽  
Serum Gonadotropin ◽  
Alpha 7 ◽  
Hydroxyeicosatetraenoic Acids ◽  
Ovulatory Process

Hydroxyeicosatetraenoic acid methyl esters (HETEs) are lipoxygenase products of arachidonic acid that are generated along with prostaglandins (PGs) during acute inflammatory reactions. Whereas it is well known that ovarian PG levels increase during the ovulatory process, little is known about ovarian HETEs. This report compares the ovarian changes in 5-, 12-, and 15-HETE with ovarian PGE and PGF, along with progesterone, 17 alpha-hydroxyprogesterone, 4-androstene-3,17-dione, testosterone, and 17 beta-estradiol. Ovulation was induced in immature Wistar rats by sequential treatment with pregnant mare's serum gonadotropin and human chorionic gonadotropin (hCG). Follicles began rupturing 10 h after hCG treatment. The greatest correlation was among 12-HETE, 15-HETE, and progesterone, which increased to peak levels at 10 h after hCG. In contrast, the ovarian levels of 5-HETE, 17 alpha-hydroxyprogesterone, testosterone, and 17 beta-estradiol all declined sharply beginning 4 h after hCG. 2 alpha,4 alpha,7-4,5-Epoxy-17-hydroxy-4,17-dimethyl-3-oxo-androstane-2- carbonitrile (epostane), a potent inhibitor of steroid synthesis and ovulation, sharply reduced the synthesis of all five steroids within 30 min after its injection at 3 h after hCG. Among the five eicosanoids, epostane mainly inhibited 15-HETE. The results suggest that 15-HETE, along with progesterone, may have an important role in ovulation.

Total synthesis and structural revision of chromomoric acid C-I and C-II methyl esters

Tetrahedron ◽  
1994 ◽  
Vol 50 (43) ◽  
pp. 12337-12348 ◽  
Author(s):  
Zhi-Yu Liu ◽  
Hong Dong ◽  
Xin-Jie Chu
Keyword(s):  
Total Synthesis ◽  
Methyl Esters ◽  
Structural Revision
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