Metalation of 14H-Dibenzo[a,h]-, 7H-Dibenzo[c,h]-, and 14H-Dibenzo[a,c]phenothiazine with n-Butyllithium

Shirley, D. A.; Gilmer, John C.

doi:10.1021/jo01059a071

Cited by 10 publications

(5 citation statements)

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“…Zander and Franke reported the synthesis of benzo[ def ]naphtho[2,3- b ]carbazole 174.4 , which could be obtained from each of the substituted benzocarbazoles 174.3a – b by means of the Elbs reaction ( 174.3b apparently underwent deacylation) . Unexpected lactamizations of dibenzophenothiazinecarboxylic acids were observed by Shirley and Gilmer, yielding the highly fused products 174.5 – 6 . This behavior was ascribed to steric effects.…”

Section: Nonbenzenoid Fusionmentioning

confidence: 99%

“…1089 Unexpected lactamizations of dibenzophenothiazinecarboxylic acids were observed by Shirley and Gilmer, yielding the highly fused products 174.5−6. 1090 This behavior was ascribed to steric effects. Interestingly, the highly fused indazolo[4,3,2-hij]quinoline motif is found in two commercial Indanthrene dyes, Navy Blue R (174.7) and Gray M (174.8).…”

Section: Chemical Reviewsmentioning

confidence: 99%

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Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds: Synthetic Routes, Properties, and Applications

et al. 2016

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Two-dimensionally extended, polycyclic heteroaromatic molecules (heterocyclic nanographenes) are a highly versatile class of organic materials, applicable as functional chromophores and organic semiconductors. In this Review, we discuss the rich chemistry of large heteroaromatics, focusing on their synthesis, electronic properties, and applications in materials science. This Review summarizes the historical development and current state of the art in this rapidly expanding field of research, which has become one of the key exploration areas of modern heterocyclic chemistry.

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Section: Nonbenzenoid Fusionmentioning

confidence: 99%

Section: Chemical Reviewsmentioning

confidence: 99%

Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds: Synthetic Routes, Properties, and Applications

et al. 2016

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“…The importance of "well-hydrated" protoplasm must be stressed, for dehydration increases both heat and cold resistance (117). Baker (12), Lorenz (134), and Shirley (183) found no significant differences between species of tree seedlings in relation to lethal temperatures. But Weddell and Ware (235) Variables between species that may affect relative fire resistance include bark thickness and composition, growth form, sprouting ability, typical growing site, and fuel accumulation in a typical site (190).…”

Section: Intermediate Factors In Heat Resistancementioning

confidence: 97%

“…It is apparent from the above discussion that the term "lethal temperature" has little meaning unless the time factor is also indicated. The time required for killing bacteria by heat increased in a geometrical progression as the temperature was lowered arithmetically (26 Baker (12), Lorenz (134), and Shirley (183) investigated the lethal temperature-time curves of tree tissues by heating seedlings in a water bath. Baker studied stem injury in conifers by heating the tops only, the roots being protected in soil or water.…”

Section: 900 (20)mentioning

confidence: 99%

“…-Theoretically transpiration should cool the leaf by removing the latent heat of vaporization, but the practical importance of this process has long been debated. Shirley (183) found the heat resistance of conifer seedlings to be higher in air than in water, and highest in dry air. This difference he ascribed to the cooling effect of transpiration.…”

Section: Physical Factors In Heat Resistancementioning

confidence: 99%

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Heat effects on living plants /

Hare¹

1961

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Heteroatom‐Facilitated Lithiations

Gschwend¹,

Rodriguez²

1979

Organic Reactions

185

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Some 25 years have elapsed since the topic of metalation reactions was reviewed by Gilman and Morton. The intervening years have been notable for intensive explorations in this area, in part because many organolithium reagents are now commercially available. Specifically, research efforts have been characterized by the discovery of new functional groups that promote metalation, elaboration of novel heterocyclic and olefinic substrates as metalatable species, recognition of new types of lithiating agents, and the continuation of efforts to define accurately the mechanism of metalation. Accordingly, heteroatom‐facilitated lithiation has become recognized as an increasingly important tool, not only in the elaboration of carbocyclic aromatic and heteroaromatic systems, but also in synthetic aliphatic chemistry. A few recent reviews have covered the topic in a more limited or less specific sense. It is the purpose of this chapter to survey and classify the vast accumulation of heteroatom‐facilitated lithiations recorded since the first coverage in Organic Reactions . As outlined by Gilman and Morton, the terms “metalation” in general and “lithiation” in particular denote any replacement of a hydrogen atom by metal or lithium. In this review, however, lithiation is defined as the exchange of a hydrogen atom attached to an sp 2 ‐hybridized carbon atom by lithium to form a covalent lithium‐carbon bond. More specifically, discussion is limited to those metalations that, through the influence of a heteroatom, are characterized by rate enhancement and regioselectivity. In fact, lithiation reactions of this type are noted for an extraordinarily high degree of regioselectivity, metalation generally occurring on the sp 2 ‐carbon atom closest to the heteroatom. Based on the relative position of the heteroatom, such lithiations are conveniently classified into two principal categories: alpha and beta ( ortho ) lithiations. In alpha lithiations the metalating agent deprotonates the sp 2 ‐carbon atom alpha to the heteroatom to form a carbonlithium bond. This sp 2 ‐carbon atom may be part of an olefinic or heteroaromatic π system. In beta lithiations the metalating agent is directed to deprotonate the sp 2 ‐carbon atom beta to the heteroatom‐containing substituent. The sp 2 ‐carbon atom can be part of an aromatic or an olefinic π system. It should be noted that the designation “ ortho metalation” is used specifically for the beta metalation of carbocyclic aromatic systems. This chapter surveys all systems in which alpha and beta lithiations have been observed, with the exception of ferrocenes.

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Metalation of 14H-Dibenzo[a,h]-, 7H-Dibenzo[c,h]-, and 14H-Dibenzo[a,c]phenothiazine with n-Butyllithium

Cited by 10 publications

References 0 publications

Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds: Synthetic Routes, Properties, and Applications

Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds: Synthetic Routes, Properties, and Applications

Heat effects on living plants /

Heteroatom‐Facilitated Lithiations

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