Iodolactonization of 4-Pentenoic Acid

Brckner et al [12] described a new application to the synthesis of 4-carboxy- -lactones from butenolides by employing LiC(SMe)3 and MeI to obtain the 4-[tris(methylsulfonyl)methyl] derivative which under a Lewis acid-assisted hydrolisis with Hg (II) led to the carboxy group (Scheme 1) Brckner et al [12] described a new application to the synthesis of 4-carboxy- -lactones from butenolides by employing LiC(SMe)3 and MeI to obtain the 4-[tris(methylsulfonyl)methyl] derivative which under a Lewis acid-assisted hydrolisis with Hg (II) led to the carboxy group (Scheme 1)

Iodolactonization of 3

The reaction of (S)-3-N-Cbz-4-pentenoic acid with iodine in acetonitrile in the presence of AgOTf gave the cis-iodo-lactone 6 in excellent yield and in a highly diastereoselective manner The substitutions of the iodine in 6 by different Grignard reagents in the presence of CuI and the subsequent conversions into the functionalized syn-γ-hydroxy-β-amino acids have been investigated

Single-amino acid substitution studies of D-Nal(2′) 7-ACTH1-17 indicate that amino acid residues 15-17 in N-D-Nal(2′)7-ACTH1-17 are crucial for hMC3R and hMC4R activation Substitutions of these amino acid residues reduced or abolished agonist activity at hMC3R and hMC4R

The effects of 4-pentenoic acid on substrate oxidations and on the distribution of coenzyme A and its derivatives were studied in isolated rat liver mitochondria CoA-linked substrate long and short chain fatty acid pyruvate and cw-ketoglutarate oxidations were inhibited 60 to 80% by 0 1 rnM 4-pentenoic acid

A single example of an asymmetric iodolactonization promoted by a stoichiometric amount of a titanium TADDOL complex had already been reported in 1992 by Taguchi 74 The enantiomeric excess achieved was moderate and the reaction had to be conducted with α-hydroxycarboxylic acid to allow for chelation in the metal complex More efficient substoichiometric iodolactonizations are possible using

4-pentenoic acid from laboratory scale (1 mL 50 mM substrate) to preparative scale and to assess the environmental impact To determine the environmental impact of the reaction the E+-factor 20 a recent extension of Sheldon'sE-Received: December 16 2019 Revised: January 24 2020

Iodolactonization of 4

An experiment in which 4-pentenoic acid is converted into a lactone via iodolactonization is described In this lab activity the alkenoic acid is treated with I 2 prepared in situ forming an iodonium ion that undergoes intramolecular nucleophilic attack to produce 5-iodo-γ-valerolactone Students use the infrared spectrum to determine which functional groups are present in the product and

ELECTRONMICROSCOPIC AND ENERGIC ASPECTS IN 4-PENTENOIC ACID INDUCED-FATTY LIVER MODEL OF REYE'S SYNDROME ICHIRO YOSHIDA Department of Pediatrics Kurume University School of Medicine Kurume 830 Japan Received for publication August 25 1979 The 4-pentenoic acid one of short-chain fatty acids produced fatty

Cyclization of 2-Methylene-4-pentenoic Acids Dissection: H I K = Halogen SeR' H2cQo Raucher et a1 15" used the Claisen ortho ester rearrange- ment which leads directly to the desired arrangement of carboxyl group and terminal CC double bond i e to the y amp unsaturated carboxylic acid or 4-pentenoic acid cycli- zation was accomplished via seleno-lactonization

Although R-lactic acid can be used for the synthesis of herbicides the development of alternative methods to S-2-chloropropinoic acid alleviate this need (see Chapter 3) 5 5 4 3-Hydroxybutyric Acid This hydroxy acid is available as the R-isomer from the biodegradable polymer Biopol [33]

Effect of Ti(Oi-Pr)4 on Stereoselectiviy of Halocyclization of 2-Substituted 4-Pentenoic Acid and 4-Penten-1-ol (1991/01 Chem Lett ) Michael Addition of 2 2-Difluoroketene Silyl Acetal Preparation of 4 4-Difluoroglutamic Acid and 5 5-Difluorolysine (1990/08 Chem Lett ) Atom-transfer Reaction of Difluoroiodoacetate (1990/06 Chem

Asymetric Synthesis of -Amino Acids through -Iodination of Chiral Unsaturated Carboxamides and Stereoselective Iodolactonization Effect of Ti(Oi-Pr)4 on Stereoselectiviy of Halocyclization of 2-Substituted 4-Pentenoic Acid and 4-Penten-1-ol Preparation of 4 4-Difluoroglutamic Acid

Penicillic acid was isolated from Aspergillus sclerotiorum and converted into 6-iodo-α-pyran-2 5-diones using iodolactonization a key intermediate for the synthesis of pectinolide F Structures of penicillic acid and its iodolactonized product were confirmed by using NMR experiments

The only byproduct (2% according to GC-MS) which was not isolated and was not characterized had a mass that corresponded to chlorolactone 6 When iodolactonization of 4-pentenoic acid was done in dichloromethane the same byproduct formed in a larger amount (8–10%)

Reagent‐Controlled Asymmetric Iodolactonization Using

Abstract A novel method for reagent‐controlled asymmetric iodolactonization of 5‐aryl‐4‐pentenoic acids is reported This work uses carboxylate ion pairs combined with cinchona alkaloids as chiral sources of carboxylate anion for the first time leading to a mixture of two regio‐isomeric iodolactones with moderate enantioselectivity (exo‐18 5% ee endo‐35 0% ee) under mild

Effect of Ti(Oi-Pr)4 on Stereoselectiviy of Halocyclization of 2-Substituted 4-Pentenoic Acid and 4-Penten-1-ol (1991/01 Chem Lett ) Michael Addition of 2 2-Difluoroketene Silyl Acetal Preparation of 4 4-Difluoroglutamic Acid and 5 5-Difluorolysine (1990/08 Chem Lett ) Atom-transfer Reaction of Difluoroiodoacetate (1990/06 Chem

acid nucleus—obtained by fermentation—and simple chemical transformations [59] The side chain amino acid is d-phenylglycine the synthesis of which is discussed in Chapter 8 The use of enzymes to form the amide bond has many advantages over the alternative chemical approaches that usually involve reactive intermediates [17 18 60]

1 Introduction The γ-butyrolactone is a characteristic skeletal core present in a large amount of natural products and biological compounds including pharmaceuticals and agrochemicals such as ascorbic acid [] pheromones [] plant growth regulator karrikin [] and anti-HIV nucleoside β-FddA [] Development of efficient methods for the synthesis of various functionalized lactones has

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