Listar Ciencias básicas por procedencia "UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Química"
Mostrando ítems 1-20 de 276
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1,1-Diphenyl-4-(thiophen-2-yl)but-3-yn-1-ol
(2018-11)The asymmetric unit of the title homopropargyl alcohol, C20H16OS, contains two independent molecules comprising a hydroxy group, a 3-(2-thiophenyl)- propargylic moiety and two aromatic rings linked to a central carbon atom. ... -
1,3-Bis{[(2,6-dimethylphenyl)sulfanyl]methyl}benzene
(2019)The structure of the title compound, C24H26S2, an example of a pincer ligand with an SCS-chelation motif, illustrates the steric effects of the methyl groups in the thiophenyl rings at the 2- and 6-positions, forcing a ... -
1-Nitro-4-(1-propyn-1-yl)benzene
(2019)The title compound, C9H7NO2, was prepared by alkynylation of 4-iodonitrobenzene with 1,3-dilithiopropyne in the presence of 1 equivalent of CuI and catalytic amounts of Pd(PPh3)2Cl2. The complete molecule is generated ... -
(1S,3R)-N-{(3S,10S,12S,13R,17R)-12-Hydroxy-17- [(R)-5-hydroxypentan-2-yl]-10,13-dimethylhexa- decahydro-1H-cyclopenta[a]phenanthren-3-yl}- adamantane-1-carboxamide 0.25-hydrate
(2022-10-12)The title compound, C 35H 57 NO 3 0.25H 2O, was synthesized from deoxycholic acid followed by a protection, a Mitsonobu substitution, a Staudinger reduction, formation of an amide and final reduction in the lateral chain. ... -
5,5-Diphenyl-cis-penta-2,4-dienoic acid
(2019)In the title compound, C17H14O2, the dihedral angle between the phenyl rings is 76.52 (7)°. In the crystal, pairwise O—H⋯O hydrogen bonds link the molecules into carboxylic acid inversion dimers. -
A Chronoamperometric Screen Printed Carbon Biosensor Based on Alkaline Phosphatase Inhibition for W(VI) Determination in Water, Using 2-Phospho-l-Ascorbic Acid Trisodium Salt as a Substrate
(2015)This paper presents a chronoamperometric method to determine tungsten in water using screen-printed carbon electrodes modified with gold nanoparticles and cross linked alkaline phosphatase immobilized in the working ... -
A facile method for the preparation of bishomopropargylic alcohols from acyl chlorides
(2014)Controlled dilithiation of propargyl bromide with two equivalents of n-butyllithium, in the presence of TMEDA, produces the operational equivalent of the dianion 1,3-dilithiopropyne. The latter reacts efficiently with ... -
A Facile Method for the Titration of Organolithium Reagents using Naphtylamine or Naphtylmethylamine as Indicators
(2019)A simple method for the titration of alkyllithiums with sec-butanol, using naphtylamine or naphtylmethylamine as color indicator, is reported. Both amines gave sharp-end points, easily determined by color changes from ... -
A High-Throughput Screen Identifies a New Natural Product with Broad-Spectrum Antibacterial Activity
(2012)Due to the inexorable invasion of our hospitals and communities by drug-resistant bacteria, there is a pressing need for novel antibacterial agents. Here we report the development of a sensitive and robust but low-tech and ... -
A new and efficient synthesis of (3E,8Z,11Z)-tetradeca-3,8,11-trienyl acetate, the major sex pheromone component of the tomato leafminer Tuta absoluta
(2018)An efficient synthesis of (3E,8Z,11Z)-tetradeca-3,8,11-trienyl acetate, the major sex pheromone component of the tomato leafminer moth, Tuta absoluta, was accomplished. The synthesis started with but-3-yn-1-ol and gave an ... -
A new method for the preparation of 1,3-dilithiopropyne: an efficient synthesis of homopropargyl alcohols
(2001)Controlled dilithiation of propargyl bromide with two equivalents of n-butyllithium, in the presence of TMEDA, produces the operational equivalent of the dianion 1,3-dilithiopropyne. The latter reacts efficiently with ... -
A New Method for the Preparation of 1,5-Diynes. Synthesis of (4E,6Z,10Z)-4,6,10-Hexadecatrien-1-ol, the Pheromone Component of the Cocoa Pod Borer Moth Conopomorpha cramerella
(2004)A new method for the synthesis of 1,5-diynes, from the reaction of 1,3-dilithiopropyne and propargyl chlorides, was developed. This new methodology was used to prepare (4E,6Z,10Z)-4,6,10-hexadecatrien-1-ol, one of the ... -
A New Method for the Preparation of 1-Ethynyl Ethers
(1994)During our study of the stannylcupration of acetylenic ethers we required [2-13C]-1 for mechanistic studies. Existing methods for the synthesis of acetylenic ethers involve dehydrohalogenation of 2-halo, ... -
A new methodology for the synthesis of δ-substituted α,β-unsaturated δ-lactones
(2020)A new protocol for the synthesis of δ-substituted-α,β-unsaturated δ-lactones was developed. Selective reaction of 1,3-dilithiopropyne with ketones, followed by addition of ethyl chloroformate formed ethyl 5-[(ethoxycarbo ... -
Aceites esenciales, fenología e interacciones bióticas de la planta invasora Crassocephalum crepidioides (Asteraceae) en Costa Rica
(2022-12)Crassocephalum crepidioides (Asteraceae) es una especie herbácea con notables usos etnobotánicos en África y otras áreas, que se extendió como invasora en varias regiones tropicales y subtropicales del mundo. Objetivo: ... -
Adipostatins E-J, new potent antimicrobials identified as inhibitors of coenzyme-A biosynthesis
(2020-01)Phosphopantetheine is a key structural element in biological acyl transfer reactions found embedded within coenzyme A (CoA). Phosphopantothenoylcysteine synthetase (PPCS) is responsible for installing a cysteamine group ... -
Aggregation Pheromone of Palm Weevil, Dynamis borassi
(1997)4-Methyl-5-nonanol (1) is the male-produced aggregation pheromone of the palm weevil, Dynamis borassi (F.) from Colombia. The pheromone was identified by coupled gas chromatographic–electroantennographic detection (GC-EAD) ... -
Aggregation pheromone of palmetto weevil, Rhynchophorus cruentatus (F.) (Coleoptera: Curculionidae)
(1994)5-Methyl-4-octanol is the major aggregation pheromone of the palmetto weevil,Rhynchophorus cruentatus (F.). The pheromone (cruentol) was identified by coupled gas chromatographic-electroantennographic (GC-EAD) analysis of ... -
Aggregation Pheromone of the African Rhinoceros Beetle, Oryctes monoceros (Olivier) (Coleoptera: Scarabaeidae)
(1994)Coleoptera, Oryctes monoceros, African Rhinoceros Beetle, Aggregation Pheromone, Ethyl 4-M ethyloctanoate Ethyl 4-m ethyloctanoate is a male-produced aggregation pheromone of the African rhinoceros beetle, Oryctes monoceros ... -
Aggregation Pheromones and Host Kairomones of West Indian Sugarcane Weevil, Metamasius hemipterus sericeus
(1997)Coupled gas chromatographic–electroantennographic detection (GC-EAD) analyses and coupled GC-mass spectrometry (MS) of volatiles produced by male and female West Indian sugarcane weevils (WISW), Metamasius hemipterus ...