Minerals and Organic Nitrogen Present in Grape Marc Hydrolyzates Enhance Xylose Consumption by <Emphasis Type="Italic">Lactobacillus pentosus</Emphasis>

This work deals with the nutritional evaluation of grape marc hydrolyzates as fermentation medium for Lactobacillus pentosus. Usually, the fermentation of xylose and arabinose in the presence of glucose remains a primary obstacle for economical biomass conversion. The few microorganisms that can grow simultaneously on both pentose and hexose sugars contained in lignocellulosic feedstocks typically grow slowly and demonstrate marginal yields and productivities. Moreover, lignocellulosic hydrolyzates contain phenolic compounds and other components originated by the degradation of sugars that can inhibit lactic acid fermentation. However, in this case, grape marc hydrolyzates not only did not need a detoxification stage, but it also improved the xylose consumption by Lactobacillus pentosus with a faster and more efficient conversion of hemicellulosic sugars compared with synthetic media. After analysis of grape marc hydrolyzates, it was observed that minerals such as K (2,707 mg/L), Ca (3,681 mg/L), and Mg (198.5 mg/L) are present in higher concentration than those found in the general medium of Lactobacillus (1,705 mg/L of K, 58.3 mg/L of Ca, and 27.0 mg/L of Mg). Moreover, grape marc hydrolyzates contain an additional source of nitrogen (9.2 g/L) which, together with their elevated mineral concentration, improved lactic acid fermentation compared with synthetic media.     

HRGC and GC–MS analysis of essential oil from colombian ylang-ylang (Cananga odorata Hook fil. et Thomson,forma genuina)

Samples of essential oil from Colombian ylang-ylang trees were analyzed by means of HRGC, HRGC–MS, IR and ¹H- and ¹³C-NMR. 57 components were detected, 51 of which were positively identified. Camphene and anethol were identified in ylang-ylang essential oil for the first time. Among the composition-determining variables studied (extraction time, part of the flower, and flower freshness), the extraction time and the flower condition (fresh versus dry) were found to have the largest incidence in the quality of the essential oil.     

Synthesis of substituted 1-benzyl-2,4,6-triphenyl-2,3-dihydro-pyrazolo [3,4-b] [1,4]diazepines

The acid catalyzed condensation of 4,5-diaminopyrazoles and chalcones gave the hitherto unknown 1-benzyl-2,4,6-triphenyl-2,3-dihydropyrazolo[3,4-b][1,4]diazepines derivatives. The structure of all products was supported by ir, ¹H and ¹³C-nmr and mass spectra.     

Analysis of volatile secondary metabolites from Colombian Xylopia aromatica (Lamarck) by different extraction and headspace methods and gas chromatography

Hydrodistillation (HD), simultaneous distillation-solvent extraction (SDE), microwave-assisted hydrodistillation (MWHD), and supercritical fluid (CO2) extraction (SFE), were employed to isolate volatile secondary metabolites from Colombian Xylopia aromatica (Lamarck) fruits. Static headspace (S-HS), simultaneous purge and trap (P&T) in solvent (CH2Cl2), and headspace (HS) solid-phase microextraction (SPME) were utilised to obtain volatile fractions from fruits of X. aromatica trees, which grow wild in Central and South America, and are abundant in Colombia. Kováts indices, mass spectra or standard compounds, were used to identify more than 50 individual components in the various volatile fractions. beta-Phellandrene was the main component found in the HD and MWHD essential oils, SDE and SFE extracts (61, 65, 57, and ca. 40%, respectively), followed by beta-myrcene (9.1, 9.3, 8.2 and 5.1%), and alpha-pinene (8.1, 7.3, 8.1 and 5.9%). The main components present in the volatile fractions of the X. aromatica fruits, isolated by S-HS, P&T and HS-SPME were beta-phellandrene (53.8, 35.7 and 39%), beta-myrcene (13.3, 12.3 and 10.1%), p-mentha-1(7),8-diene (7.1, 10.6 and 10.4%), alpha-phellandrene (2.2, 5.0 and 6.4%), and p-cymene (2.2,4.7 and 4.4%), respectively.     

Complete assignment of 1H and 13C NMR data for three aryltetralin lignan lactones

We describe the complete 1H and 13C NMR analysis of three aryltetralin lignan lactones (polygamain, morelensin and 4,5-dimethoxymorelensin) using modern NMR techniques such as COSY, HMQC, HMBC, 2D-J-resolved and NOE experiments. The relative stereochemistry of these compounds, which is very important with regard to their biological activity, was completely determined.     

Cathodic stripping determination of halides in mixtures

Cathodic stripping voltammetry is evaluated for the simultaneous determination of chloride, bromide and iodide in mixtures. Results are similar to those obtained with ion-selective electrodes. Detection limits are 177 μg l^?1 for chloride, 40 μg l^?1 for bromide, and 8 μg l?1 for iodide. Dam water and human spinal fluid were analyzed satisfactorily.     

(E)‐3‐{2‐Amino‐4‐ethoxy‐6‐[N‐(4‐methoxyphenyl)‐N‐methylamino]pyrimidin‐5‐yl}‐1‐phenylprop‐2‐en‐1‐one: a boat‐shaped pyrimidine ring and a chain of hydrogen‐bonded R42(8) and R22(20) rings

In the title compound, C₂₃H₂₄N₄O₃, the pyrimidine ring adopts an almost perfect boat conformation, and the bond distances provide evidence for some polarization of the molecular–electronic structure. Two independent N—H...O hydrogen bonds link the molecules into chains of edge‐fused R²₄(8) and R²₂(20) rings.     

Comparison of different extraction methods for the analysis of volatile secondary metabolites of Lippia alba (Mill.) N.E. Brown, grown in Colombia, and evaluation of its in vitro antioxidant activity

Hydrodistillation (HD), simultaneous distillation solvent extraction (SDE), microwave-assisted hydrodistillation (MWHD), and supercritical fluid (CO2) extraction (SFE) were employed to isolate volatile secondary metabolites from fresh leaves and stems of Colombian Lippia alba (Mill.) N.E. Brown. Kovàts indices, mass spectra or standard compounds were used to identify around 40 components in the various volatile fractions. Carvone (40-57%) was the most abundant component, followed by limonene (24-37%), bicyclosesquiphellandrene (5-22%), piperitenone (1-2%), piperitone (ca. 1.0%), and beta-bourbonene (0.6-1.5%), in the HD, SDE, MWHD, and SFE volatile fractions. Static headspace (S-HS), simultaneous purge and trap in solvent (CH2Cl2) (P&T), and headspace solid-phase microextraction (HS-SPME) were used to sample volatiles from fresh L. alba stems and leaves. The main components isolated from the headspace of the fresh plant material were limonene (27-77%), carvone (14-30%), piperitone (0.3-0.5%), piperitenone (ca. 0.4%), and beta-bourbonene (0.5-6.5%). The in vitro antioxidant activity of L. alba essential oil, obtained by hydrodistillation was evaluated by determination of hexanal, the main carbonyl compound released by linoleic acid subjected to peroxidation (1 mm Fe2+, 37 degrees C, 12 h), and by quantification of this acid as its methyl ester. Under the same conditions, L. alba HD-essential oil and Vitamin E exhibited similar antioxidant effects.     

Natural (5-oxoheptene-1E,3E-dienyl)-5,6-dihydro-2H-pyran-2-one: total synthesis and revision of its absolute configuration

The synthesis of (5^′-oxoheptene-1^′E,3^′E-dienyl)-5,6-dihydro-2H-pyran-2-one has been performed in seven steps using four key steps: a ring-closing metathesis reaction to build up the unsaturated lactone, a Wittig reaction to control the C6-C7 (E) double bond, a cross-metathesis reaction to control the (E) double bond at C8-C9, and an enantioselective allyltitanation to control the absolute configuration at C5. Spectroscopic data (IR, MS, ¹H, and ¹³C NMR) were identical to those of the natural compound except for the optical rotation, which led us to re-assign the absolute configuration of the natural product.     

2,5‐Dimethyl‐6,7‐dihydrobenzo[h]pyrazolo[1,5‐a]quinazoline and 2‐tert‐butyl‐5‐methyl‐6,7‐dihydrobenzo[h]pyrazolo[1,5‐a]quinazoline

In both 2,5‐dimethyl‐6,7‐dihydrobenzo[h]pyrazolo[1,5‐a]quinazoline, C₁₆H₁₅N₃, (I), and 2‐tert‐butyl‐5‐methyl‐6,7‐dihydrobenzo[h]pyrazolo[1,5‐a]quinazoline, C₁₉H₂₁N₃, (II), which crystallizes with Z′ = 2 in the space group P, the non‐aromatic carbocyclic rings adopt screw‐boat conformations. The molecules of (I) are linked into chains of rings by a combination of C—H...N and C—H...π(arene) hydrogen bonds, while in (II) there are no hydrogen bonds of any kind.