Synthesis of para-olivetol depsides

1974 ◽  
Vol 27 (8) ◽  
pp. 1767 ◽  
Author(s):  
JA Elix
Keyword(s):  
Bond Formation ◽  
Trifluoroacetic Anhydride ◽  
Ester Bond ◽  
Catalytic Hydrogenolysis

The unambiguous synthesis of the lichen depsides, anziaic, perlatolic, 2'-O-methylanziaic, 2-O- methylperlatolic, 2'-O-methylperlatolic, 4-O-demethylplanaic, planaic, imbricaric and stenosporic acids is reported. Where necessary the phenolic and carboxy groups of the intermediate phenols were protected by O-benzylation until after the depside-ester bond formation had been achieved by treatment with trifluoroacetic anhydride. Catalytic hydrogenolysis of the depside esters so formed subsequently gave the natural acids.

One-Pot Access to 4-Aryl-2-arylacetoxynaphthalenes via Benz­annulation of Oxygenated Arylacetic Acids and Alkyl Aryl Ketones

Synthesis ◽  
2020 ◽  
Vol 52 (07) ◽  
pp. 1035-1046 ◽  
Author(s):  
Meng-Yang Chang ◽  
Shin-Mei Chen ◽  
Yu-Ting Hsiao
Keyword(s):  
Bond Formation ◽  
Trifluoroacetic Anhydride ◽  
Ring Closure ◽  
One Pot ◽  
Alkyl Aryl ◽  
Highly Effective ◽  
Aryl Ketones ◽  
Arylacetic Acids ◽  
Plausible Mechanism

Trifluoroacetic anhydride mediated one-pot intermolecular formal (4+2) benzannulation of oxygenated arylacetic acids with alkyl aryl ketones provides 4-aryl-2-arylacetoxynaphthalenes in moderate to good yields in the presence of H3PO4 in an open-vessel in a straightforward procedure. A plausible mechanism is proposed and discussed. This protocol provides a highly effective ring-closure via two carbon–carbon (C–C) and one carbon–oxygen (C–O) bond-formation events.

N,N-Dialkyl-N′-Chlorosulfonyl Chloroformamidines in Heterocyclic Synthesis. Part XIII. Cleavage and Rearrangement Reactions of Pyrazolo[1,5-b][1,2,4,6]thiatriazine 1,1-Dioxides

2016 ◽  
Vol 69 (1) ◽  
pp. 61 ◽  
Author(s):  
Rebecca E. Norman ◽  
Michael V. Perkins ◽  
Andris J. Liepa ◽  
Craig L. Francis
Keyword(s):  
Ethyl Acetate ◽  
Dimethyl Sulfoxide ◽  
Trifluoroacetic Acid ◽  
Sulfonic Acid ◽  
Trifluoroacetic Anhydride ◽  
Ring Cleavage ◽  
Thermal Rearrangement ◽  
Heterocyclic Synthesis ◽  
Similar Treatment ◽  
Catalytic Hydrogenolysis

Treatment of pyrazolo[1,5-b][1,2,4,6]thiatriazines 1 with the Vilsmeier–Haack reagent afforded pyrazolo[1,5-a][1,3,5]triazines 5. Reaction of compounds 1 with trifluoroacetic anhydride, dimethyl sulfoxide, and triethylamine afforded 5-dimethylsulfanylidene derivatives 8. The guanidino-pyrazole-sulfonic acid 9 was produced from treatment of compounds 1 with trifluoroacetic acid under anhydrous conditions. Similar treatment in the presence of water afforded the desulfonated pyrazolo-guanidine 6. Reactions of 6 with one-carbon electrophiles provided various 4-substituted pyrazolo[1,5-a][1,3,5]triazines 5. Attempted catalytic hydrogenolysis of N7-benzyl pyrazolo[1,5-b][1,2,4,6]thiatriazines 2 in alcohols led to sulfamates 12 from thiatriazine ring cleavage. Ethyl acetate or tert-butanol as solvent allowed successful debenzylation to provide compounds 1. Aminolysis of compounds 2 gave sulfamides 13. Thermal rearrangement of compounds 2 afforded 6-benzyl-pyrazolo[3,4-e][1,2,4]thiadiazines 14.

Notizen: Unusual Formation of Carbamate Salts: an Experimental Proof for the Mechanism of the Removal of Carbobenzoxy Group by Catalytic Hydrogenolysis

1978 ◽  
Vol 33 (10) ◽  
pp. 1196-1197 ◽  
Author(s):  
István Schőn ◽  
Lajos Kisfaludy
Keyword(s):  
Chemical Structure ◽  
Bond Formation ◽  
Peptide Bond ◽  
Carbamic Acid ◽  
Peptide Bond Formation ◽  
Solvent Concentration ◽  
Experimental Proof ◽  
Catalytic Hydrogenolysis ◽  
Neutral Conditions ◽  
Unusual Formation

Abstract Carbamate Salts, Catalytic Hydrogenolysis Catalytic hydrogenolysis of Z-Gly-NH2 and Z-Ala-NH2 resulted in the corresponding free amides and carbamate salts. This observation is a further experimental proof that carbamic acid derivatives are intermediates of hydrogen-olytic removal of carbobenzoxy group under neutral conditions. The ratio of the formation of the two compounds is dependent on the solvent, concentration and chemical structure. The carbamate salts can be acylated without difficulties under the conditions of peptide bond formation.

scholarly journals Understanding the mechanism of ester bond formation in bacterial adhesins

2017 ◽  
Vol 73 (a2) ◽  
pp. C226-C226
Author(s):  
Yuliana Yosaatmadja ◽  
Ted Baker ◽  
Paul Young ◽  
Christopher Squire
Keyword(s):  
Bond Formation ◽  
Ester Bond ◽  
Bacterial Adhesins

scholarly journals Structural Insights into the Free-Standing Condensation Enzyme SgcC5 Catalyzing Ester-Bond Formation in the Biosynthesis of the Enediyne Antitumor Antibiotic C-1027

Biochemistry ◽  
2018 ◽  
Vol 57 (23) ◽  
pp. 3278-3288 ◽  
Author(s):  
Chin-Yuan Chang ◽  
Jeremy R. Lohman ◽  
Tingting Huang ◽  
Karolina Michalska ◽  
Lance Bigelow ◽  
...  
Keyword(s):  
Bond Formation ◽  
Ester Bond ◽  
Antitumor Antibiotic ◽  
Free Standing ◽  
Structural Insights

scholarly journals Zeolite-Based Catalysts: A Valuable Approach toward Ester Bond Formation

Catalysts ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 758 ◽  
Author(s):  
Nadia Fattahi ◽  
Konstantinos Triantafyllidis ◽  
Rafael Luque ◽  
Ali Ramazani
Keyword(s):  
Organic Synthesis ◽  
Size Structure ◽  
Bond Formation ◽  
Industrial Processes ◽  
Ester Bond ◽  
Laboratory Studies ◽  
Catalytic Systems ◽  
Wide Range ◽  
Catalytic Applications ◽  
Insight Into

Zeolite-based catalysts are versatile catalytic systems for a wide range of laboratory studies and industrial scale processes. The chemical composition, ion exchange, and pore size structure attributes of zeolites are responsible for their extensive catalytic applications. Esterification is one of the most important and routinely processes in diverse fields of organic synthesis. It has a long history in both industrial processes and laboratory work due to its versatility. This review intends to give a detailed insight into the significance of zeolite-based catalysts for ester bond formation

Sign in / Sign up

Export Citation Format

Share Document