A Mild Transesterification Method

Mori, Kazuo; Tominaga, Mineko; Takigawa, Tadahiro; Matsui, Michiko

doi:10.1055/s-1973-22304

Cited by 105 publications

(39 citation statements)

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“…JH titers were analyzed on a Trace 2000 series gas chromatograph (GC) coupled to a Finnigan Polaris mass spectrometer detector (MS). An internal standard, JH III ethyl ester, was made from synthetic JH III (Sigma, St. Louis, MO) by using a mild transesteriÞcation method (Mori et al 1973, Liu et al 2004) and quantiÞed on the same GC-MS system (Liu et al 2004). The GC was equipped with a DB-5MS column (30 m by 0.25 mm by 0.25 m, J & W ScientiÞc, Folsom, CA).…”

Section: Methodsmentioning

confidence: 99%

Formosan Subterranean Termite (Isoptera: Rhinotermitidae) Soldiers Regulate Juvenile Hormone Levels and Caste Differentiation in Workers

Mao

Henderson

Liu

et al. 2005

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A caste structure is maintained in termite societies and juvenile hormone (JH) is generally regarded as the most important regulator in these termite colonies. Here, we demonstrate that the soldier caste regulates JH in workers of Coptotermes formosanus Shiraki. Worker termites (80 Ð100 individuals) were placed in petri dishes with 0, 5, 10, or 20% soldiers. JH III titers of groups of these workers were monitored at 14, 28, 42, and 56 d. Any changes in soldier caste proportions also were noted at each sample date. On the Þrst sample date, the JH levels in workers were similar among treatments with different initial soldier proportions, and no new soldiers were formed. Over the next three sample dates, the worker JH levels were higher for low initial soldier proportion treatments and vice versa. Concurrently, soldier formation increased with lower initial soldier proportions. JH titers in workers showed a positive and statistically signiÞcant relationship to soldier numbers until a certain soldier proportion was reached. These results provide evidence that soldier caste proportions regulate JH levels and thereby caste differentiation in workers. The means by which this regulatory mechanism may proceed is discussed.

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Section: Methodsmentioning

confidence: 99%

Formosan Subterranean Termite (Isoptera: Rhinotermitidae) Soldiers Regulate Juvenile Hormone Levels and Caste Differentiation in Workers

Mao

Henderson

Liu

et al. 2005

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“…4 ) This transesterification is mild enough to prevent the equilibration of the geometry of the C-2 double bond due to enolization of the ester carbonyl group. These ethyl esters (VII) were epoxidized as usual to give another set of JH Tables I and II as expressed in termes of the percentages of larvae molted into larva.…”

Section: Synthesis and Biological Activity Of Jh Analogs With Carbomementioning

confidence: 99%

Effect of the Molecular Chain Length on Biological Activity of Juvenile Hormone Analogs

Mori

Takigawa

Manabe

et al. 1975

Agricultural and Biological Chemistry

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“…The methyl (12), cyclopentyl (16), and benzyl (17) acetate derivatives were prepared via transesterification [47], by refluxing the ethyl ester 13 in the suitable alcohol in the presence of a catalytic amount of sodium cyanide. The same catalyst was used for aminolysis [48] of 13 with an excess of pyrrolidine at 50 ± 558 to yield the amide 18.…”

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confidence: 99%

Lipophilicity Plays a Major Role in Modulating the Inhibition of Monoamine Oxidase B by 7‐Substituted Coumarins

Carotti

Altomare

Catto

et al. 2006

Chemistry & Biodiversity

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A series of coumarin derivatives (1-22), bearing at the 7-position ether, ketone, ester, carbamate, or amide functions of varying size and lipophilicity, were synthesized and investigated for their in vitro monoamine oxidase-A and -B (MAO-A and -B) inhibitory activities. Most of the compounds acted preferentially as MAO-B inhibitors, with IC(50) values in the micromolar to low-nanomolar range. A structure-activity-relationship (SAR) study highlighted lipophilicity as an important property modulating the MAO-B inhibition potency of 7-substituted coumarins, as shown by a linear correlation (n=20, r(2)=0.72) between pIC(50) and calculated log P values. The stability of ester-containing coumarin derivatives in rat plasma provided information on factors that either favor (lipophilicity) or decrease (steric hindrance) esterase-catalyzed hydrolysis. Two compounds (14 and 22) were selected to investigate how lipophilicity and enzymatic stability may affect in vivo MAO activities, as assayed ex vivo in rat. The most-potent and -selective MAO-B inhibitor 22 (=7-[(3,4-difluorobenzyl)oxy]-3,4-dimethyl-1-benzopyran-2(2H)-one) within the examined series significantly inhibited (>60%) ex vivo rat-liver and striatal MAO-B activities 1 h after intraperitoneal administration of high doses (100 and 300 mumol kg(-1)), revealing its ability to cross the blood-brain barrier. At the same doses, liver and striatum MAO-A was less inhibited in vivo, somehow reflecting MAO-B selectivity, as assessed in vitro. In contrast, the metabolically less stable derivative 14, bearing an isopropyl ester in the lateral chain, had a weak effect on hepatic MAO-B activity in vivo, and none on striatal MAO-B, but, surprisingly, displayed inhibitory effects on MAO-A in both peripheral and brain tissues.

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A Mild Transesterification Method

Cited by 105 publications

References 0 publications

Formosan Subterranean Termite (Isoptera: Rhinotermitidae) Soldiers Regulate Juvenile Hormone Levels and Caste Differentiation in Workers

Formosan Subterranean Termite (Isoptera: Rhinotermitidae) Soldiers Regulate Juvenile Hormone Levels and Caste Differentiation in Workers

Effect of the Molecular Chain Length on Biological Activity of Juvenile Hormone Analogs

Lipophilicity Plays a Major Role in Modulating the Inhibition of Monoamine Oxidase B by 7‐Substituted Coumarins

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