Isolation and reactivity of a model for the carbodiimide-carboxylic acid adduct. O-Benzoyl-N,N-dimethyl-N'-(N-methyl-2,4-dinitroanilino)isourea

Hegarty, A. F.; McCormack, Margaret T.; Ferguson, G. A.; Roberts, Patrick D.

doi:10.1021/ja00448a075

Cited by 37 publications

(6 citation statements)

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“…It is also noteworthy that, whether the substituent is electron‐releasing (methyl) or electron‐withdrawing (Cl), on the 1‐aza‐2‐azoniaallene cation or the carbodiimide, the substituent on the exocyclic CN double bonds of product 4 and imino‐hydrogen inside of the ring are cis ‐oriented with respect to each other. Such configuration is indeed observed in the experiment6 and was verified by other similar theoretical work29, 30.…”

Section: Resultssupporting

confidence: 87%

The cellular composition of neurogenic periventricular zones in the adult zebrafish forebrain

Lindsey

Darabie

Tropepe

2012

J of Comparative Neurology

116

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A central goal of adult neurogenesis research is to characterize the cellular constituents of a neurogenic niche and to understand how these cells regulate the production of new neurons. Because the generation of adult-born neurons may be tightly coupled to their functional requirement, the organization and output of neurogenic niches may vary across different regions of the brain or between species. We have undertaken a comparative study of six (D, Vd, Vv, Dm, Dl, Ppa) periventricular zones (PVZs) harboring proliferative cells present in the adult forebrain of the zebrafish (Danio rerio), a species known to possess widespread neurogenesis throughout life. Using electron microscopy, we have documented for the first time the detailed cytoarchitecture of these zones, and propose a model of the cellular composition of pallial and subpallial PVZs, as well as a classification scheme for identifying morphologically distinct cell types. Immunolabeling of resin-embedded tissue confirmed the phenotype of three constitutively proliferating (bromodeoxyuridine [BrdU]+) cell populations, including a radial glial-like (type IIa) cell immunopositive for both S100β and glutamine synthetase (GS). Our data revealed rostrocaudal differences in the density of distinct proliferative populations, and cumulative labeling studies suggested that the cell cycle kinetics of these populations are not uniform between PVZs. Although the peak numbers of differentiated neurons were generated after ~2 weeks among most PVZs, niche-specific decline in the number of newborn neurons in some regions occurred after 4 weeks. Our data suggest that the cytoarchitecture of neurogenic niches and the tempo of neuronal production are regionally distinct in the adult zebrafish forebrain.

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Section: Resultssupporting

confidence: 87%

The cellular composition of neurogenic periventricular zones in the adult zebrafish forebrain

Lindsey

Darabie

Tropepe

2012

J of Comparative Neurology

116

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“…In spite of the wide use of DCC as a condensation agent in the preparation of amides (particularly in the peptide field), to our knowledge there have been no previous reports on the isolation of IV-cyclohexylamides as byproducts in this type of reaction, DCC was verified not to contain any detectable amount of cyclohexylamine prior to its addition to the reaction mixture. We speculate that the O-acylurea-postulated as the primary reaction product from the interactions of the carboxylic acid and the diimide (Hegarty at al., 1977)-rearranges to an IV-acylurea, which in turn can be cleaved by the nucleophilic species of the medium, affording either the normal acyl derivative or the IV-cyclohexylamide depending on the reaction conditions (see also Avramovici-Grisaru and Sarel, 1982). In this context, work is in progress to clarify the origins and scope of these processes.…”

Section: Resultsmentioning

confidence: 98%

Byproduct identification in the carbodiimide-assisted synthesis of fatty acid anilides related to Spanish Toxic Oil Syndrome

Freixa¹,

Casas²,

Messeguer³

et al. 1986

J. Agric. Food Chem.

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Results are presented on the comprehensive analytical identification of the N-cyclohexylamides obtained as unexpected reaction byproducts in the synthesis of N-phenyloleamide (NPOA) and N-phenyllinoleamide (NPLA) by reaction of anilide with either oleic or linoleic acid. The data presented prove that these N-cyclohexylamide impurities (5-25%) are due to the MN'-dicyclohexylcarbodiimide used as dehydrating agent. The synthesis of both phenylamides was required for toxicological testing in relation to the Spanish Toxic Oil Syndrome. Purification of the reaction crudes by silica gel column chromatography followed by subsequent TLC and HPLC assay of the presumably pure amides did not eliminate the cyclohexylamides, which had not been detected by either technique. Unequivocal identifications were achieved by a combined analytical approach involving packed and capillary GC and GC-MS, chemical ionization MS, IR and NMR spectroscopy, and elemental analysis. On the basis of the above results, an alternative procedure is suggested, leading to the desired amides in high purity and good yields.

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“…Dicyclohexylcarbodiimide (DCC) has been reported to proceed via a similar O-N acyl rearrangement from the O-acylisourea intermediate to form N-acylurea, which does not have an acylating ability. 11,12) Several acylating reagents possessing an amide moiety such as N-acylimidazoles, 13) N-acylureas, 14) N-acylsuccinimides, 15,16) and N-acylbenzotriazoles 17) have also been reported. However, it is necessary to activate a carboxylic acid by using a condensing reagent to introduce each leaving group.…”

Section: Inroductionmentioning

confidence: 99%

<i>N</i>-Acyltriazinedione; a Novel Acylating Reagent Synthesized from a Triazinone-Type Condensing Reagent

Yamada

Lee

Kota

et al. 2021

CHEMICAL & PHARMACEUTICAL BULLETIN

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Isolation and reactivity of a model for the carbodiimide-carboxylic acid adduct. O-Benzoyl-N,N-dimethyl-N'-(N-methyl-2,4-dinitroanilino)isourea

Cited by 37 publications

References 0 publications

The cellular composition of neurogenic periventricular zones in the adult zebrafish forebrain

The cellular composition of neurogenic periventricular zones in the adult zebrafish forebrain

Byproduct identification in the carbodiimide-assisted synthesis of fatty acid anilides related to Spanish Toxic Oil Syndrome

<i>N</i>-Acyltriazinedione; a Novel Acylating Reagent Synthesized from a Triazinone-Type Condensing Reagent

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