The Structure and Synthesis of 4-Oxypannaric Acid 2-Methyl Ester, a Dibenzofuran From the Lichen Leproloma diffusum

1994 ◽  
Vol 47 (4) ◽  
pp. 703 ◽  
Author(s):  
JA Elix ◽  
JA Elix ◽  
R Naidu ◽  
R Naidu ◽  
JR Laundon ◽  
...  
Keyword(s):  
Methyl Ester ◽  
Total Synthesis ◽  
Dimethyl Ester ◽  
Partial Synthesis

The structure of the major dibenzofuran present in the lichen Leproloma diffusum has been shown to be that of 4-oxypannaric acid 2-methyl ester (2-methyl hydrogen 3,4,9-trihydroxy-1,7-dimethyldibenzofuran-2,6-dicarboxylate) (2). The structure of (2) was confirmed by total synthesis, achieved through a biomimetic-type approach using palladium(II) acetate in the key cyclization step. Partial synthesis of the corresponding dimethyl ester (8) was effected starting from natural pannaric acid 6-methyl ester (6).

Stereoselective total synthesis of preclavulone-A methyl ester and its diastereomer

2004 ◽  
Vol 45 (9) ◽  
pp. 1941-1944 ◽  
Author(s):  
Hisanaka Ito ◽  
Masami Konishi ◽  
Kazuo Iguchi
Keyword(s):  
Methyl Ester ◽  
Total Synthesis

A Total Synthesis of Spirastrellolide A Methyl Ester

2013 ◽  
Vol 19 (11) ◽  
pp. 3596-3608 ◽  
Author(s):  
Alexander Arlt ◽  
Stefan Benson ◽  
Saskia Schulthoff ◽  
Barbara Gabor ◽  
Alois Fürstner
Keyword(s):  
Methyl Ester ◽  
Total Synthesis ◽  
Spirastrellolide A

ChemInform Abstract: Stereocontrolled Total Synthesis of (.+-.)-Pentalenolactone P Methyl Ester.

ChemInform ◽  
2010 ◽  
Vol 23 (12) ◽  
pp. no-no
Author(s):  
H.-J. KANG ◽  
C. S. RA ◽  
L. A. PAQUETTE
Keyword(s):  
Methyl Ester ◽  
Total Synthesis

scholarly journals Stereoselective total syntheses of (±)-sinularene and (±)-5-epi-sinularene: a general intramolecular Diels–Alder approach to tricyclic sesquiterpenes

1985 ◽  
Vol 63 (4) ◽  
pp. 993-995 ◽  
Author(s):  
Kazimierz Antczak ◽  
John F. Kingston ◽  
Alex G. Fallis
Keyword(s):  
Double Bond ◽  
Methyl Ester ◽  
Total Synthesis ◽  
Ring System ◽  
Diels Alder ◽  
Exocyclic Double Bond ◽  
Total Syntheses ◽  
Methyl Group ◽  
Secondary Hydroxyl ◽  
Selective Hydrogenolysis

Stereoselective total synthesis of (±)-sinularene and (±)-5-epi-sinularene are described. The sequence employs a "blocked" cyclopentadiene in which the cyclopropane unit also serves as a latent methyl group. Thus intramolecular [4 + 2] cycloaddition of the substituted methyl spiro[2.4]hepta-4,6-dien-1-yl)-2-pentenoate 11 affords 5-benzyloxy-6-isopropyl-8-carbomethoxytetracyclo[5.4.01,7.02,4.02,9]undec-10-ene (12) which after selective hydrogenolysis generates the tricyclo[4.4.01,6.02,8]decane (sinularene) ring system. Removal of the secondary hydroxyl function (Ph3P/CCl4/CH3CN; H2/Pd/C), reduction of the methyl ester (LiAlH4), and introduction of the exocyclic double bond (acetate pyrolysis, 550 °C) completes the synthesis of (±)-sinularene in 14 steps from cyclopentadiene. A parallel series of reactions employing the isopropyl epimer of 12 affords (±)-5-epi-sinularene.

Significance of C-terminal cysteine modifications to the biological activity of the Saccharomyces cerevisiae a-factor mating pheromone

1991 ◽  
Vol 11 (7) ◽  
pp. 3603-3612
Author(s):  
S Marcus ◽  
G A Caldwell ◽  
D Miller ◽  
C B Xue ◽  
F Naider ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Biological Activity ◽  
Methyl Ester ◽  
Total Synthesis ◽  
Biologically Active ◽  
Structural Genes ◽  
Wild Type ◽  
Mating Pheromone ◽  
Carboxy Terminal

We have undertaken total synthesis of the Saccharomyces cerevisiae a-factor (NH2-YIIKGVFWDPAC[S-farnesyl]-COOCH3) and several Cys-12 analogs to determine the significance of S-farnesylation and carboxy-terminal methyl esterification to the biological activity of this lipopeptide mating pheromone. Replacement of either the farnesyl group or the carboxy-terminal methyl ester by a hydrogen atom resulted in marked reduction but not total loss of bioactivity as measured by a variety of assays. Moreover, both the farnesyl and methyl ester groups could be replaced by other substituents to produce biologically active analogs. The bioactivity of a-factor decreased as the number of prenyl units on the cysteine sulfur decreased from three to one, and an a-factor analog having the S-farnesyl group replaced by an S-hexadecanyl group was more active than an S-methyl a-factor analog. Thus, with two types of modifications, a-factor activity increased as the S-alkyl group became bulkier and more hydrophobic. MATa cells having deletions of the a-factor structural genes (mfal1 mfa2 mutants) were capable of mating with either sst2 or wild-type MAT alpha cells in the presence of exogenous a-factor, indicating that it is not absolutely essential for MATa cells to actively produce a-factor in order to mate. Various a-factor analogs were found to partially restore mating to these strains as well, and their relative activities in the mating restoration assay were similar to their activities in the other assays used in this study. Mating was not restored by addition of exogenous a-factor to a cross of a wild-type MAT alpha strain and a MATaste6 mutant, indicating a role of the STE6 gene product in mating in addition to its secretion of a-factor.

Total Synthesis of Zincophorin and Its Methyl Ester

2004 ◽  
Vol 69 (14) ◽  
pp. 4626-4647 ◽  
Author(s):  
Magali Defosseux ◽  
Nicolas Blanchard ◽  
Christophe Meyer ◽  
Janine Cossy
Keyword(s):  
Methyl Ester ◽  
Total Synthesis
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