Synthese und Eigenschaften von 7‐substituierten Thieno[3,2‐c]cumarin‐2‐carbonsäureestern

Weißenfels, M.; Hantschmann, Achim; Steinführer, Thorsten; Birkner, E.

doi:10.1002/zfch.19890290503

Cited by 16 publications

(2 citation statements)

References 7 publications

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“…42 Thieno[3,2-c]coumarins have also been prepared by the reaction of 4-chloro-3-formylcoumarin with a thioglycolate and 1,4-dithiane-2,5-diol or a combination of sodium sulfide and chloroacetaldehyde. [43][44][45][46][47][48] In following the second approach (the construction of the pyrone), the palladium-catalyzed carbonylation of 2-(3-thienyl)phenol leads to the formation of thieno[3,2-c]coumarins. 49,50 The target coumarins have also been prepared by the cyclization of alkyl (2-methoxy)aryl-2-thienylcarboxylates and -3thienylcarboxylates in the presence of BBr 3 and t-BuOK.…”

Section: Letter Synlettmentioning

confidence: 99%

l-Proline-Catalyzed Three-Component Reaction of 4-Chloro-3-formylcoumarin, Sodium Sulfide, and α-Halo Ketones: A Direct Approach to Thieno[3,2-c]coumarins

Thotathil

Al‐Zoubi

Sawali

et al. 2022

Synlett

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A new protocol for the synthesis of thieno[3,2-c]coumarins is disclosed herein. Following this method, 3-formyl-2-oxo-2H-chromene-4-thiolate is in-situ generated by the combination of 4-chloro-3-formylcoumarin and sodium sulfide. This chromene-4-thiolate undergoes L-proline catalyzed substitution/Knoevenagel cascade with α-haloketone to afford the desired thieno coumarins in moderate to good isolated yields. The described protocol eliminates the need for stoichiometric amounts of inorganic bases and the use of foul smelling thiols. The reaction conditions tolerate a variety of α-haloketone.

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Section: Letter Synlettmentioning

confidence: 99%

l-Proline-Catalyzed Three-Component Reaction of 4-Chloro-3-formylcoumarin, Sodium Sulfide, and α-Halo Ketones: A Direct Approach to Thieno[3,2-c]coumarins

Thotathil

Al‐Zoubi

Sawali

et al. 2022

Synlett

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“…The fused compounds 59 and 60 absorb violet light with maxima at 404 and 395 nm and emit blue light at 480 and 486 nm with large quantum efficiencies (0.82 and 1.00, respectively) in MeCN. [36] The Stokes shifts (76 nm and 91 nm) were found to be somewhat larger than the Stokes shift for 7-diethylamino-4-methylcoumarin (63 nm [21g] ) in the same solvent. Replacement of the methyl group at C-4 in compounds 44 and 151 with an amino group led to coumarins 61-69, 134 and 135 (see Figure 13 and Table 6), and this was accompanied by a hypsochromic shift in the absorption bands by 10−15 nm and by a hypsofluoric shift of the emission bands by approximately 20−30 nm.…”

Section: Large Stokes Shift Fluorophores 121 Fluorophores With a Stok...mentioning

confidence: 96%

Fluorescent Dyes with Large Stokes Shifts of 80−200 nm for Optical Microscopy and Nanoscopy

Sednev¹

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TheVilsmeier Reaction of Fully Conjugated Carbocycles and Heterocycles

Jones

Stanforth

1996

Organic Reactions

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In 1925 Fischer, Müller, and Vilsmeier published a paper describing the reaction between phosphoryl chloride and N ‐methylacetanilide, giving a number of products, including the quinolinium salt and another salt. The probable course of the reaction was given in a paper by Vilsmeier and Haack in 1927, and they made the important discovery that the reagent obtained from N ‐methylformanilide and phosphoryl chloride, represented as a salt, would react with N,N ‐dimethylaniline, giving 4‐ N,N ‐dimethylaminobenzaldehyde. No 2‐substituted products were observed in this reaction. Other N,N ‐dialkylaniline derivatives, including 3, N,N ‐trimethylaniline and 1‐ N,N ‐dimethylaminonaphthalene were also successfully used as substrates to prepare aromatic aldehyde derivatives. The gradual development of the reagent for synthesis was accompanied by interest in the nature of the reagent. It was discovered that other acid chlorides (e.g., thionyl chloride, carbonyl chloride, and oxalyl chloride) could be used in the reaction and that substituted amides other than formamides gave ketones, although in generally poorer yields. Thionyl chloride frequently gives sulfur‐containing products. The most commonly used amide is dimethylformamide (DMF) and there is now a consensus that the reagent formed from DMF and most acid chlorides, other than phosphoryl chloride, can be represented by the structure given in the chapter, and this is illustrated for the reaction between DMF and carbonyl chloride. The salt is a stable compound and is often isolated before being reacted with a substrate. It seems likely that the most commonly used reagent, that made from DMF and phosphoryl chloride, is an equilibrium mixture of iminium salts. Recent unpublished spectroscopic studies have indicated that in DMF solution there is an equilibrium mixture of iminium compounds. One of the electrophilic chloroiminium salts then reacts with a substrate in an electrophilic substitution process yielding an iminium salt, which is usually hydrolyzed to the aromatic aldehyde. Vinylogous chloroiminium salts can be prepared from the corresponding vinylogous formamide derivatives and these yield, after hydrolysis, α,β‐unsaturated products. This particular reaction is generally limited to more reactive substrates. The formation of carbon–carbon bonds to fully conjugated carbocycles and heterocycles is the subject of this chapter; a subsequent chapter considers carbon–carbon bond‐formation reactions in alkenes (including heterosubstituted alkenes such as enamines and enol ethers), alkynes, and activated methyl and methylene compounds (aldehydes, ketones, carboxylic acid derivatives, and nitriles). It is not surprising that the Vilsmeier reaction has been the subject of many review articles of varying scope and length. With so many excellent reviews dealing with the Vilsmeier reaction, its mechanism, and the structure of the various electrophilic reagents, coverage is restricted to important concepts rather than reiterate all the literature material. A brief description of the mechanism and regiochemistry of the Vilsmeier reaction is presented and this is elaborated with appropriate cases that deal with specific compound types.

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Synthese und Eigenschaften von 7‐substituierten Thieno[3,2‐c]cumarin‐2‐carbonsäureestern

Cited by 16 publications

References 7 publications

l-Proline-Catalyzed Three-Component Reaction of 4-Chloro-3-formylcoumarin, Sodium Sulfide, and α-Halo Ketones: A Direct Approach to Thieno[3,2-c]coumarins

l-Proline-Catalyzed Three-Component Reaction of 4-Chloro-3-formylcoumarin, Sodium Sulfide, and α-Halo Ketones: A Direct Approach to Thieno[3,2-c]coumarins

Fluorescent Dyes with Large Stokes Shifts of 80−200 nm for Optical Microscopy and Nanoscopy

TheVilsmeier Reaction of Fully Conjugated Carbocycles and Heterocycles

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