Stobbe condensation

Weaving is the most widely used textile manufacturing technique and accounts for the majority of the two-dimensional 2-D fabric produced Stobbe and Mohamed, Thus condensation of the Grignard Reagents of 2-bromopropyl-1,3-dioxolane with various acylthiophenes or thiophenecarboxylic esters produced the intermediate alcohols a ; Scheme Coupling reactions Condensation reactions Carbon-carbon bond forming reactions Name reactions. Thienyl and benzo[ b ]thienyl ketones exhibit reactivities characteristic of aromatic ketones, including Claisen condensation, Schmidt, Beckmann and Mannich reactions and hypohalite oxidation of methyl ketones. Wittig reactions on thiophenecarbaldehydes have been used to extend the side chain.

Uploader: Mazull
Date Added: 13 January 2016
File Size: 51.45 Mb
Operating Systems: Windows NT/2000/XP/2003/2003/7/8/10 MacOS 10/X
Downloads: 33571
Price: Free* [*Free Regsitration Required]





The greater resonance energy of thiophene compared with furan results in being a major contributor in the thienyl system relative to in the furyl series. Also applicable to heteroaromatic aldehydes.

Illustrated Glossary of Organic Chemistry - Stobbe condensation

Enolate equivalents and modified acceptors, primarily a 3 -synthons, have been introduced that obviate these complications. Woven structures have the greatest history of application in textile manufacturing.

Alkylated 2,4,5,6,7,8-hexahydroazulene derivatives were also prepared by reacting the cindensation of Step 2 with methyl lithium in diethyl ether overnight as illustrated in Eq. Cd Disconnect Products Michael B. Filtration, washing water and drying gave 5. Triaxial fabrics possess exceptional mechanical properties in several directions.

Next, condensaation carbonyl carbon of the other ester is nucleophilically attacked by the enolate anion. Mechanistically, silyl enol ether formation occurs initially, followed by fluoride ion catalyzed enolate formation. Thus condensation of the Grignard Reagents of 2-bromopropyl-1,3-dioxolane with various acylthiophenes or thiophenecarboxylic esters produced the intermediate alcohols a ; Scheme In contrast to the paucity of citations concerning additions of organolithiums or Grignard reagents to vinyl sulfoxides, ketone enolate additions are highly precedented.

As expected, because of their relationship to naphtho[1,2- b ]-pyrans, the h -fused compounds show a slow thermal fade, although this can be modified by substitution in the 2,2-diaryl rings.

Condensaation use cookies to help provide and enhance our service and tailor content and ads. The warp and weft yarns in a woven fabric can be interlaced in various ways, called a weave structure.

Stobbe condensation

In contrast, Mukaiyama reports that tin II enolates of alicyclic ketones, e. Hydroxylamine- O -sulfonic acid converts thiophenecarbaldehyde into the nitrile in high yield under mild conditions. Two new procedures are available for the conversion of acetylthiophenes to thienylacetic acids.

Mark Heron, in Progress in Heterocyclic Chemistry Rajappa, in Comprehensive Heterocyclic Chemistry Other bridged analogues, IIIhave been prepared and are described 3. The h -fused benzothienobenzopyrans also show slow fading.

Coupling reactions Condensation reactions Carbon-carbon bond forming reactions Name reactions. Thereafter, the product was purified as described in Step 3 and isolated. Jones has reported several prototypical prostaglandin syntheses in which ketone enolates and ethyl acetoacetate dianion are added to vinyl sulfoxides and ; Scheme The reactions of some other carbenes derived from diazomethylthiophenes have been referred conxensation in Section 3.

From Wikipedia, the free encyclopedia. E in the Stobbe condensation product depended on temperature, catalyst and relative size of R 2 and R 3but generally favored the E configuration at higher temperatures.

Condensation Synthesis Aldehydes application acid ester chemical reaction product chemical reaction procedure. For example, azaenolates, e.

Stobbe condensation - an overview | ScienceDirect Topics

A reaction mechanism that explains the formation of both an ester group and a carboxylic acid group is centered on a lactone intermediate By using this site, you agree to the Terms of Use and Privacy Policy. For example, with E -acceptors, the Z -enolates afford high anti -selectivity while the E -enolates and afford high syn -selectivity Scheme The Stobbe condensation [5] is a modification specific stobe the condenastion ester of succinic acid requiring less strong bases.

In addition, increasing substitution on the enolates enhances the formation of 1,4-addition products. The Stobbe disconnection is.

Thienyl and benzo[ b ]thienyl ketones exhibit reactivities characteristic of aromatic ketones, including Claisen condensation, Schmidt, Beckmann and Mannich reactions and hypohalite oxidation of methyl ketones.

3 thoughts on “Stobbe condensation”

Leave a Reply

Your email address will not be published. Required fields are marked *