Notes - Formylation of Thianaphthene with N-Methylformanilide

Ghaisas, V. V.

doi:10.1021/jo01357a614

Cited by 11 publications

(2 citation statements)

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“…Their results in the preparation of thionaphthene-3-aldehyde were recently confirmed by Gnaisas 135 . In contrast to thionaphthene, 4,5,6,7-tetrahydrothionaphthene yields a 2-aldehyde 136 .…”

Section: -Bromothiophene-2-aldehyde Is Obtained If Pobr 3 Is Used Inmentioning

confidence: 71%

Formylation and Acylation of Organic Compounds With Substituted Amides of Carboxylic Acids

Dorofeenko¹

1960

Russ. Chem. Rev.

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Section: -Bromothiophene-2-aldehyde Is Obtained If Pobr 3 Is Used Inmentioning

confidence: 71%

Formylation and Acylation of Organic Compounds With Substituted Amides of Carboxylic Acids

Dorofeenko¹

1960

Russ. Chem. Rev.

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“…A small amount of 5-formyl product has been found along with the 3-formyl derivative of j'-guaiazulene (78). The formylation product of thianaphthene has definitely been shown to be the 3isomer (37).…”

Section: Mechanism and Product Studiesmentioning

confidence: 98%

Friedel-Crafts Acylations.

Nelson¹

1959

Ind. Eng. Chem.

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Friedel-Crafts Acylations 1 he leveling off noted two years ago and the decline last year in the number and variety of Friedel-Crafts acylations seem to have stabilized. The fertile ingenuity of organic chemists continues to provide unique and interesting examples of this important reaction. This reaction class still continues to provide one or more key links in the successful synthesis of complex molecules in such diverse fields as dyes, perfumes, steroids, terpenes. alkaloids, and antibiotics as well as many more directly obvious applications.The tabulation form established in previous reviews is undergoing an experimental test of major importance. The tables with complete lists of references will be provided separately by the editor in photoprint form for those who need them. CatalystsThe importance of polyphosphoric acid as a mild reagent for effecting ringclosure acylations is a significant factor in the appearance of an extensive review of this reagent's utility (60).Zinc oxide is claimed to be a very effective nonhalogen catalyst for aryl acylations (61). Better yields with less undesirable by-products are obtained when nitromethane is included in the reaction medium for acylating phenols and phenol ethers. Tetrachloroethane seemed to be the most desirable solvent (64). Silicon tetraacetate gave only moderate or fair yields of 2-acetylthiophene with stannic chloride, zinc Cilio-. LeROI NELSON is associate professor of organic chemistry at Brigham Young University. He graduated from Utah State Agricultural College and obtained his Ph.D. from Purdue University in 1952. Previous experience includes postdoctoral research at UCLA and teaching at Purdue and Wayne Universities. Nelson is a member of the ACS,

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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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Notes - Formylation of Thianaphthene with N-Methylformanilide

Cited by 11 publications

References 1 publication

Formylation and Acylation of Organic Compounds With Substituted Amides of Carboxylic Acids

Formylation and Acylation of Organic Compounds With Substituted Amides of Carboxylic Acids

Friedel-Crafts Acylations.

TheVilsmeier Reaction of Fully Conjugated Carbocycles and Heterocycles

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