Search results for "Synthesis"

Effect of allyl isothiocyanate on transcriptional profile, aflatoxin synthesis, and Aspergillus flavus growth.

2020

Abstract The goals of this study were to determine the efficacy of allyl isothiocyanate (AITC) against the growth of A. flavus and Aflatoxin B1 (AFB1) production as well as to evaluate changes in the transcriptome profile when colonizing maize. A. flavus was inoculated in potato dextrose agar (PDA), the plates were placed inside glass jars and the mycelial growth (MG) was monitored for 7 d. Likewise, maize grains were contaminated with A. flavus in glass jars of 1 L and treated with 0.125, 0.25, 0.5, 1 and 5 µL of AITC. The moisture content (MC) of grains was 15 and 21%. After 7 days of storage, the MG was significantly reduced in doses higher than 0.125 µL/L of AITC. All doses of AITC redu…

Intramuscular sex steroid hormones are associated with skeletal muscle strength and power in women with different hormonal status

2015

International audience; Estrogen (E2)-responsive peripheral tissues, such as skeletal muscle, may suffer from hormone deficiency after menopause potentially contributing to the aging of muscle. However, recently E2 was shown to be synthesized by muscle and its systemic and intramuscular hormone levels are unequal. The objective of the study was to examine the association between intramuscular steroid hormones and muscle characteristics in premenopausal women (n = 8) and in postmenopausal monozygotic twin sister pairs (n = 16 co-twins from eight pairs) discordant for the use of E2-based hormone replacement. Isometric skeletal muscle strength was assessed by measuring knee extension strength.…

Histaprodifens: synthesis, pharmacological in vitro evaluation, and molecular modeling of a new class of highly active and selective histamine H(1)-r…

2000

A new class of histamine analogues characterized by a 3, 3-diphenylpropyl substituent at the 2-position of the imidazole nucleus has been prepared outgoing from 4,4-diphenylbutyronitrile (4b) via cyclization of the corresponding methyl imidate 5b with 2-oxo-4-phthalimido-1-butyl acetate or 2-oxo-1,4-butandiol in liquid ammonia, followed by standard reactions. The title compounds displayed partial agonism on contractile H(1) receptors of the guinea-pig ileum and endothelium-denuded aorta, respectively, except 10 (histaprodifen; 2-[2-(3, 3-diphenylpropyl)-1H-imidazol-4-yl]ethanamine) which was a full agonist in the ileum assay. While 10 was equipotent with histamine (1), methylhistaprodifen (…

ATP and endogenous agonists inhibit evoked [3H]-noradrenaline release in rat iris via A1 and P2y-like purinoceptors.

1993

Effects of ATP, adenosine and purinoceptor antagonists on field stimulation-evoked (3 Hz, 2 min) [3H]-noradrenaline overflow were investigated in the rat isolated iris. ATP and adenosine inhibited the evoked overflow of [3H]-noradrenaline. 1,3-Dipropyl-8-cyclopentylxanthine (DPCPX) shifted the concentration-response curve of ATP to the right in a concentration-dependent manner, but with a potency (-log KB = 7.88) much lower than expected for an A1 adenosine receptor. In the continuous presence of DPCPX, the ATP-induced prejunctional inhibition was unaffected by suramin (100 mumol/l) and DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid, 50 mumol/l) but was antagonized by the P2Y-rece…

ChemInform Abstract: “One-Pot” Synthesis of Raumacline from Ajmaline.

2010

Tuning The Selectivity To Aldehyde Via Ph Regulation In The Photocatalytic Oxidation Of 4-Methoxybenzyl Alcohol And Vanillyl Alcohol By Tio2 Catalysts

2021

Abstract The influence of pH on the photocatalytic partial oxidation of 4-methoxybenzyl alcohol (MBA) and vanillyl alcohol (VA) to their corresponding aldehydes in aqueous suspension under UVA irradiation was investigated by using poorly crystalline home-prepared and crystalline commercial TiO2 (BDH, Merck and Degussa P25) photocatalysts. The results clearly show as tuning pH can strongly impart selectivity and activity to photocatalytic processes which are often quite unselective in aqueous suspensions. It was found that pH effect on reaction rate and product selectivity strongly depended on TiO2 crystallinity and substrate type. In the case of MBA oxidation, photoreactivity and selectivit…

One-pot synthesis of polysubstituted indolizines by an addition/cycloaromatization sequence.

2013

Indolizines carrying various substituents in positions 5-8 were obtained from readily available 2-(1H-pyrrol-1-yl)nitriles and α,β-unsaturated ketones or aldehydes in a one-pot procedure. Michael addition of the deprotonated aminonitriles to the acceptors followed by acid-catalyzed electrophilic cyclization produces 5,6-dihydroindolizine-5-carbonitriles. From these stable intermediates, substituted indolizines were obtained via base-induced dehydrocyanation.

Stereoselective anti aldol reactions of erythrulose derivatives. Functionalized chiral d3 and d4 synthons.

2004

An improved procedure for the synthesis of anti aldols from protected erythrulose derivatives is reported. The preparation of functionalized d3 and d4 synthons with various stereochemical arrays by means of this methodology is described and subsequently applied to a stereoselective formal synthesis of the natural metabolite goniothalesdiol.

Bis(oxazoline) Lewis Acid Catalyzed Aldol Reactions of PyridineN-Oxide Aldehydes—Synthesis of Optically Active 2-(1-Hydroxyalkyl)pyridine Derivatives…

2006

A new, short, and simplified procedure for the synthesis of optically active pyridine derivatives from pro-chiral pyridine-N-oxides is presented. The catalytic and asymmetric Mukaiyama aldol reaction between ketene silyl acetals and 1-oxypyridine-2-carbaldehyde derivatives catalyzed by chiral copper(II)-bis(oxazoline) complexes gave optically active 2-(hydroxyalkyl)- and 2-(anti-1,2-dihydroxyalkyl)pyridine derivatives in good yields and diastereoselectivities, and in excellent enantioselectivities-up to 99 % enantiomeric excess. As a synthetic application of the developed method, a full account for the asymmetric total synthesis of a nonnatural indolizine alkaloid is provided.

Catalytic Enantioselective Aza-Reformatsky Reaction with Cyclic Imines

2016

A catalytic highly enantioselective aza-Reformatsky reaction with cyclic aldimines and ketimines for the synthesis of chiral b-amino esters with good yields and excellent enantioselectivities is reported.Areadily available diaryl prolinol is used as a chiral ligand, ZnMe2 as a zinc source and ethyl iodoacetate as reagent in the presence of air atmosphere. The reaction with cyclic ketimines generates a quaternary stereocenter with excellent levels of enantioselectivity. Furthermore, five-membered N-sulfonyl ketimines were used as electrophiles with good enantiomeric excesses, under the optimized reaction conditions. Moreover, several chemical transformations were performed with the chiral b-…