Formylation of Benzopyrones. II. Formylation of Hydroxycoumarins with N-Methylformanilide<sup>1</sup>

Naik, Radhey Mohan; Thakor, V. M.

doi:10.1021/jo01363a025

Cited by 8 publications

(2 citation statements)

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“…Attempts to synthesize failed for n greater than 2 (84). Highly substituted coumarins fail to undergo Vilsmeyer formylation (57). Ring closures to the peri-position of naphthalene and indoline were not successful in all cases (3,21,63).…”

Section: Unexpected Resultsmentioning

confidence: 97%

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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Section: Unexpected Resultsmentioning

confidence: 97%

Friedel-Crafts Acylations.

Nelson¹

1959

Ind. Eng. Chem.

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“…Soc., 1601 (1936). (5) The extraction period can be shortened from 40 hr. without any decrease in the yield of thiazole.2 (6) Williams and Ronzio2 carried out the condensation in butanol at 125°.…”

Section: An Improved Micro Synthesis Ofmentioning

confidence: 99%

Notes - An Improved Micro Synthesis of Thiamine-S³⁵

Verrett¹,

Cerecedo²

1957

J. Org. Chem.

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TheBaeyer–VilligerOxidation of Ketones and Aldehydes

1993

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The oxidative conversion of alicyclic ketones into lactones with permonosulfuric acid was discovered by Baeyer and Villiger in 1899, and in their honor the general process by which ketones are converted into esters or lactones is now known as the Baeyer–Villiger reaction. The literature on this synthetically useful process has been reviewed comprehensively through 1953 in Volume 9 of Organic Reactions , and less comprehensive reviews of the reaction have appeared since then. More recent investigations have led to the development of new synthetic reagents, to improvements in experimental reaction conditions, and to a better understanding of regiochemical and stereochemical aspects of the reaction. Baeyer–Villiger reactions now often can be carried out with functional group chemoselectivity and regiochemical control. Although the recent removal from commerce of 90% hydrogen peroxide and reagents based upon this oxidant are a setback to Baeyer–Villiger reaction methodology, alternative reagents, catalysts, and methods described in this review are available to fill the gaps. The definition of the Baeyer–Villiger reaction is somewhat fuzzy, and can be considered to include both ketones and aldehydes. In addition to the traditional use of organic and inorganic peracids as oxidants, examples of oxygen insertion reactions using hydrogen peroxide, alkyl peroxides, and several metal ion oxidants are considered to fall within the scope of this chapter and are included in the tabular survey.

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Formylation of Benzopyrones. II. Formylation of Hydroxycoumarins with N-Methylformanilide¹

Cited by 8 publications

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Friedel-Crafts Acylations.

Friedel-Crafts Acylations.

Notes - An Improved Micro Synthesis of Thiamine-S³⁵

TheBaeyer–VilligerOxidation of Ketones and Aldehydes

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Formylation of Benzopyrones. II. Formylation of Hydroxycoumarins with N-Methylformanilide1

Cited by 8 publications

References 0 publications

Friedel-Crafts Acylations.

Friedel-Crafts Acylations.

Notes - An Improved Micro Synthesis of Thiamine-S35

TheBaeyer–VilligerOxidation of Ketones and Aldehydes

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Formylation of Benzopyrones. II. Formylation of Hydroxycoumarins with N-Methylformanilide¹

Notes - An Improved Micro Synthesis of Thiamine-S³⁵