Ketene-S,N-acetals as synthetic intermediates for heterocycles. Reaction of ketene-S,N-acetals with aryl isocyanates.

Takahata, Hiroki; Nakajima, T.; Nakano, Masaharu; Tomiguchi, Akira; Yamazaki, Takao

doi:10.1248/cpb.33.4299

Cited by 16 publications

(3 citation statements)

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“…In research on ketene N , S -acetals as synthetic intermediates of heterocycles, , Takahata, Yamazaki, and co-workers found that [3 + 2] annulation of ketene N , S -acetals as C 2 1,2-dipoles with l,4-quinones allowed the construction of benzo[ b ]- and naphtho[l,2- b ]furans in low to moderate yields (16 examples, 8–51% yields).…”

Section: Annulation Reactionsmentioning

confidence: 99%

Chemistry of Ketene N,S-Acetals: An Overview

et al. 2016

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Push-pull alkenes, which bear electron-donating and -accepting group(s) at both termini of a C═C double bond, respectively, are of interest not only for their unique electronic properties but also for their importance as versatile building blocks in organic synthesis. In the world of ketene acetals having the push-pull alkene skeleton, ketene N,S-acetal is most likely the biggest family according to the number and types of these compounds. The first ketene N,S-acetal compound was reported in 1956. As a cyclic ketene N,S-acetal compound, nithiazine, the first lead structure of neonicotinoid insecticides, was reported in 1978. The characteristics of ketene N,S-acetals, which have the structural feature of ketene S,S-acetals and enaminones, make them versatile and easy to use, especially in cyclization and multicomponent reactions for the synthesis of various heterocyclic systems and related natural products. There has been an increasing wealth of information about the synthesis and synthetic applications of ketene N,S-acetals, especially, in recent years. This review provides comprehensive knowledge on the chemistry of ketene N,S-acetals.

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Section: Annulation Reactionsmentioning

confidence: 99%

Chemistry of Ketene N,S-Acetals: An Overview

et al. 2016

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“…1-14 and references therein). Besides being used to construct phylogenetic trees, test hypotheses about the mechanisms of mtDNA evolution, and explore population structure within species (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14), these data have encouraged the development of new statistical methods for estimating polymorphism and genetic diversity at the nucleotide level (15)(16)(17)(18) and have inspired the derivation of population genetic theory that focuses on the evolution of organelle genes (19)(20)(21)(22)(23)(24)(25)(26).…”

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Allelic variation in human mitochondrial genes based on patterns of restriction site polymorphism.

Whittam¹,

Clark²,

Stoneking³

et al. 1986

Proc. Natl. Acad. Sci. U.S.A.

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Restriction maps of 145 human mtDNAs representing samples from five geographic regions were used to construct multilocus genotypes for 28 genetic loci of the mitochondrial genome. Alleles were defined as distinct combinations of the presence or absence of polymorphic restriction sites within each locus. The 28 loci included 13 genes encoding proteins, 10 genes specifying tRNAs, 2 genes specifying rRNAs, and 3 noncoding regions consisting of the D loop, the light strand origin of replication, and the 5' noncoding sequence. In 35 comparisons of allele frequency distributions to expected distributions predicted by neutral mutation theory (assuming an infinite alleles model), the results revealed that most genetic diversity values (71%) fell within the range predicted by the neutral model; however, excesses in the frequencies of common alleles and in the number of singleton alleles within populations were observed at specific loci. Departures from the neutral mutation model are most readily explained by the effects of the recent expansion of the human population and the action of purifying selection. Coefficients of population differentiation suggest that gene flow of mtDNA types between certain geographic regions may be limited.

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“…The non-Mendelian inheritance of organelle genes (reviewed in refs. 4 and 5) is also expected to influence both the diversity and the subdivision of populations (6)(7)(8)(9)(10).…”

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Chloroplast DNA diversity is low in a wild plant, Lupinus texensis.

Banks¹,

Birky²

1985

Proc. Natl. Acad. Sci. U.S.A.

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Chloroplast DNA diversity was measured in an annual flowering plant, Lupinus texensis. Individual plants were collected from 21 local populations throughout the range of the species in Texas. Chloroplast DNA was isolated separately from each plant and digested with seven restriction enzymes. The most common form of the 150-kilobase-pair genome was cut at 134 sites, so that about 0.5 % ofthe base pairs in the genome were sampled. Of the 100 plants examined, 88 had identical restriction fragment patterns. Three variant forms were found in different local populations. Two, represented in single plants, differed from wild type in the presence or absence ofsingle restriction sites. The third variant was fixed in one of the local populations; it had lost a restriction site and also had a deletion of 4100 base pairs. The data suggest that chloroplast DNA in this plant is much less polymorphic than mitochondrial DNA from animals and is probably less polymorphic than nuclear genes in the same plant or in animals.One of the tasks of experimental population genetics is to measure the levels of genetic variability within species and populations. These data are important not only for understanding evolutionary mechanisms but also for the development of plant and animal breeding programs and of conservation programs aimed at conserving the gene pools of endangered species. For all these purposes, it is important to know the variability of genes in mitochondria and chloroplasts as well as that of nuclear genes. Although the organelle genes are relatively few in number, they play indispensable roles in the key processes of respiration and photosynthesis. Moreover, each genome may contain different levels or kinds of variability. This variability can be measured at the molecular level by using restriction endonucleases. The technique has been used principally for mitochondrial DNA (mtDNA) in animals (reviewed in refs. 1, 2) although it has been applied to a few specific nuclear genes. These studies have shown that (i) mtDNA nucleotide diversity within a species is very high and (ii) population subdivision (i.e., genotypic differences between local groups) is striking. There is a strong impression that overall genetic diversity and population subdivision may be greater for mitochondrial than for nuclear genes in animals. This is probably due in part to a higher mutation rate (3). The non-Mendelian inheritance of organelle genes (reviewed in refs. 4 and 5) is also expected to influence both the diversity and the subdivision of populations (6-10).Here we present a large-scale evaluation of genetic variability in the organelle genes of a wild plant. Chloroplast DNA (cpDNA) was studied because it is smaller, easier to isolate, and simpler in structure than mtDNA. The annual plant species, Lupinus texensis, was chosen for several reasons: nuclear gene (allozyme) variability has been investigated and is extremely high (11); parameters that may affect the genetic structure of populations, especially gene flow and life history...

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Ketene-S,N-acetals as synthetic intermediates for heterocycles. Reaction of ketene-S,N-acetals with aryl isocyanates.

Cited by 16 publications

References 0 publications

Chemistry of Ketene N,S-Acetals: An Overview

Chemistry of Ketene N,S-Acetals: An Overview

Allelic variation in human mitochondrial genes based on patterns of restriction site polymorphism.

Chloroplast DNA diversity is low in a wild plant, Lupinus texensis.

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