Chemoenzymatic Total Synthesis of ent-Oxycodone: Second-, Third-, and Fourth-Generation Strategies.

The stereoselective total synthesis of unnatural (+)-oxy­codone from phenethyl acetate is described. Absolute stereochemistry was established via microbial dihydroxylation of phenethyl acetate with the recombinant strain JM109 (pDTG601A) to the corresponding cis-cyclohexadienediol­ whose configuration provides for the absolute stereo­chemistry of the ring C of (+)-oxycodone. Intramolecular Heck cyclization was employed to establish the quaternary carbon at C-13, along with the dibenzodihydrofuran functionality. The C-14 hydroxyl was installed via SmI2-mediated radical cyclization. The synthesis of (+)-oxy­codone was completed in a total of 13 steps and an overall yield of 1.5%. Experimental and spectral data are provided for all new compounds.

The total synthesis of (+)-10-keto-oxycodone was attained from phenethyl acetate in a stereoselective manner. Absolute stereochemistry was established via enzymatic dihydroxylation of phenethyl acetate with the recombinant strain JM109 (pDTG601A) that furnished the corresponding cis-cyclohexadienediol whose configuration corresponds to the absolute stereochemistry of the ring C of (+)-10-keto-oxycodone. Intramolecular Heck reaction was utilized to establish the quaternary carbon at C-13, along with the dibenzodihydrofuran functionality. The C-14 hydroxyl and C-10 ketone were installed via SmI2-mediated radical cyclization, and oxidation of a benzylic alcohol (obtained from an intermediate nitrate azide), respectively. The synthesis of (+)-10-keto-oxycodone was completed in a total of 14 operations (21 steps) and an overall yield of ~2%. Experimental and spectral data are provided for key intermediates and new compounds.

The stereoselective total synthesis of unnatural (+)-galanthamine starting from phenethyl acetate is described. Chirality was introduced via microbial dihydroxylation of phenethyl acetate with the recombinant strain JM109 (pDTG601A) to the corresponding cis-cyclohexadi-enediol, configuration of which provided the absolute stereochemistry of the ring C of (+)-galanthamine. Intramolecular Heck cyclization was used to form the quaternary carbon and dibenzofuran functionality. The synthesis of (+)-galanthamine was completed in a total of ten steps and an overall yield of 5.5 %. Experimental and spectral data are provided for all new compounds.

An improvement in the stereoselective total synthesis of unnatural (+)‐oxycodone from phenethyl acetate is described. The total step count was reduced by conducting some chemical transformations in “one‐pot” and a change in the sequence of chemical operations was implemented, in comparison with the previously published first‐generation synthesis. The synthesis of (+)‐oxycodone was completed in a total of 12 operations (17 steps) and an overall yield of 1.6%, in comparison to our previous synthesis (13 operations, 19 steps, 1.5% yield) Experimental and spectral data are provided for all new compounds.

Z-Arg (Tos) -Pro-NHNHBoc (1) and Z-Arg (Tos) -Val-NHNHBoc (2) were prepared by the DCC, DCC-HOBt, DCC-DNp, mixed anhydride and DPPA methods. In each coupling reaction, lactam formation from the NG-tosylarginyl residue was observed, although the extent of formation was different depending not only on the carboxyl activation method but also on the kind of amino component. Addition of HOBt suppressed the formation of acylurea but did not suppress the formation of the lactam in the synthesis of 2. Addition of DNp suppressed the formation of the lactam slightly although it did not improve the yield of the target peptides. In the mixed anhydride method, a fairly large amount of the lactam was obtained in the synthesis of Z-Arg (Tos) -Pro-NHNHBoc, and a urethan-type derivative, Nα-isobutyloxycarbonyl-Pro-NHNHBoc, was also formed. However, in the case of synthesis of Z-Arg (Tos) -Val-NHNHBoc, lactam formation was suppressed compared with other activation methods and a small amount of urethan-type derivative was obtained. In both cases, the DPPA method gave a fairly good yield of the target peptide with only a trace amount of lactam formation.

From the Publisher: Frequency spectrum is a limited and valuable resource for wireless communications. A good example can be observed among network operators in Europe for the prices to pay for UMTS-frequency bands. Therefore, the first goal when designing future wireless communication systems (e.g. 4G - fourth generation) has to be the increase in spectral efficiency. The development in digital communications in the past years has enabled efficient modulation and coding techniques for robust and spectral efficient data, speech, audio and video transmission. These are the multi-carrier modulation (e.g. OFDM) and the spread spectrum technique (e.g. DS-CDMA), where OFDM was chosen for broadcast applications (DVB, DAB) as well as for broadband wireless indoor standards (ETSI HIPERLAN-II, IEEE-802.11) and the DS-CDMA was selected in mobile communications (IS-95, third generation mobile radio systems world wide, UMTS/IMT 2000). Since 1993 various combinations of multi-carrier (MC) modulation and the spread spectrum (SS) technique have been introduced and the field of MC-SS communications has become an independent and important research topic with increasing activities. New application fields have been proposed such as high rate cellular mobile, high rate wireless indoor and LMDS. It has been shown that MC-SS offers the high spectral efficiency, robustness and flexibility that is required for the next generation systems. Meanwhile, different alternative hybrid schemes such as OFDM/OFDMA, MC-TDMA, etc. have been deeply analysed and adopted in different international standards (ETSI-BRAN, IEEE-802 & MMAC). Multi-Carrier & Spread-Spectrum: Analysis of Hybrid Air Interfaces draws together all ofthe above mentioned hybrid schemes therefore providing a greatly needed resource for system engineers, telecommunication designers and researchers in order to enable them to develop, build and deploy several schemes based on MC-transmission for the next generation systems (which will be an integration of broadband multimedia services covering both 4G mobile and fixed wireless systems). Offers a complete treatment of multi-carrier, spread-spectrum (SS) and time division multiplexing (TDM) techniquesProvides an in-depth insight into hybrid multiple access techniques based on multi-carrier (MC) transmissionPresents numerous hybrid multiple access and air interface architectures including OFDM/CDMA, MC-CDMA, MC-DS-CDMA and MT-CDMACovers new techniques such as space-time coding and software radio Telecommunications engineers, hardware & software system designers and researchers as well as students, lecturers and technicians will all find this an invaluable addition to their bookshelf.

Abstract: The study aimed to investigate the fast and nondestructive method for detecting carbon and nitrogen content in citrus canopy. The multispectral imagery of Tarocco blood orange (Citrus sinensis L. Osbeck) plant canopy was obtained by a multispectral camera array mounted at an eight-rotor unmanned aerial vehicle (UAV) flying at an altitude of 100 m above the canopy in Wanzhou District of Chongqing Municipality, China. Average spectral reflectance data of the whole canopy, mature leaf areas and young leaves areas were extracted from the imagery. Two spectral pre-processing methods, multiplicative scatter correction (MSC) and standard normal variable (SNV), and two modeling methods, the partial least squares (PLS) and the least squares support vector machine (LS-SVM), were adopted and compared for their prediction accuracy of total content of nitrogen, soluble sugar and starch in the leaves. The results showed that, based on the spectral data extracted from the mature leaves in the multispectral imagery, the PLS model based on the original spectrum obtained a Rp (correlation coefficient) of 0.6469 and RMSEP (root mean squares error of prediction ) of 0.1296, suggested that it was the best for the prediction of total nitrogen content; the PLS model based on MSC (multiplicative scatter correction) spectrum pre-processing was the best for predicting total soluble sugar content (Rp=0.6398 and RMSEP=8.8891); and the LS-SVM model based on MSC was the best for the starch content prediction (Rp=0.6822 and RMSEP=14.9303). The prediction accuracy for carbon and nitrogen contents based on the spectral data extracted from the whole canopy and the young leaves were lower than that from the mature leaves. The results indicate that it is feasible to estimate the carbon and nitrogen contents by low-altitude airborne multispectral images. Keywords: citrus canopy, low-altitude remote sensing, carbon and nitrogen contents, soluble sugar, starch, estimation DOI: 10.3965/j.ijabe.20160905.2246 Citation: Liu X F, Lyu Q, He S L, Yi S L, Hu D Y, Wang Z T, et al. Estimation of carbon and nitrogen contents in citrus canopy by low-altitude remote sensing. Int J Agric & Biol Eng, 2016; 9(5): 149－157.

New series of copper(II), nickel(II), cobalt(II), zinc(II), cadmium(II), iron(III) and oxovanadium(IV) complexes of hydrazone, H 3 L, ligand derived from the condensation of S -methyldithiocarbazate and 4,6-diacetylresorcinol, in the molar ratio 1:1, has been synthesized. All the metal complexes are dimmers. The structures of the ligand and its transition metal complexes were characterized by elemental analyses, spectral (Infrared, electronic, Mass, 1 H NMR and ESR) data and magnetic susceptibility, molar conductivity measurements and thermal gravimetric analysis. The structure of the ligand is dibasic tridentate with ONS sites. The bonding sites, in all cases, are the azomethine nitrogen, phenolic oxygen and thiol sulfur atoms, as illustrated from the spectral data. The metal complexes exhibit different geometrical arrangements such as square planar, tetrahedral, square pyramidal and octahedral arrangements. Kinetic parameters (D G , D H , D S and D E ) of the metal complexes were calculated from the thermal behaviour of the metal complexes using Coats-Redfern method. The ligand and its metal complexes were screened for its antimicrobial activity against Staphylococcus aureus and Staphylococcus pyogenes as Gram-positive bacteria, Pseudomonas phaseolicola and Pseudomonas fluorescens as Gram-negative bacteria and the fungi Fusarium oxysporum and Aspergillus fumigatus .

Synthesis and structural characterisation of new iron(III) complexes with biologically relevant pyrazolyl thiosemicarbazones

Deep learning (DL) is one of the fastest-growing topics in materials data science, with rapidly emerging applications spanning atomistic, image-based, spectral, and textual data modalities. DL allows analysis of unstructured data and automated identification of features. The recent development of large materials databases has fueled the application of DL methods in atomistic prediction in particular. In contrast, advances in image and spectral data have largely leveraged synthetic data enabled by high-quality forward models as well as by generative unsupervised DL methods. In this article, we present a high-level overview of deep learning methods followed by a detailed discussion of recent developments of deep learning in atomistic simulation, materials imaging, spectral analysis, and natural language processing. For each modality we discuss applications involving both theoretical and experimental data, typical modeling approaches with their strengths and limitations, and relevant publicly available software and datasets. We conclude the review with a discussion of recent cross-cutting work related to uncertainty quantification in this field and a brief perspective on limitations, challenges, and potential growth areas for DL methods in materials science.

Thermodynamic properties of liquid-crystalline carbosilane dendrimers of the second and the fourth generation with methoxyphenylbenzoate terminal groups

A field experiment was conducted to study the response of individual leaf spectral reflectance to five levels of nitrogen fertilizer treatments in rice (Oriza sativa L.) plants. Sampling was combined through a rice canopy at upper, medium and low levels for biomass, nitrogen and water content measurements with spectral signals from the leaves. The vertical gradients of leaf biomass, nitrogen and water contents were associated with the nitrogen availability during tillering, panicle formation, initial heading and heading. Rice plants treated with the lowest rate of N could be characterized with the lowest value of gradient in leaf biomass and leaf water content and the highest value of gradient in leaf N concentration. A spectral gradient of single reflectance (R), ratio (RVI) and normalized difference (ND) of two individual reflectances was defined as this yielded a better relationship between the spectral data and leaf nitrogen concentration. The results suggested the spectral gradients may be used as an improved diagnostic tool for nitrogen status.

Available and effective methods of tetrahydroindol-4-one derivatives transformation are described, which include functionalization of the nitrogen atom, carbonyl group, side chains in positions 1,2,3,7 of the bicycle, as well as aromatization of the cyclohexene fragment in the presence of dehydrogenating agents. Original preparative approaches to the synthesis of [4,5]-fused indole derivatives (pyrroles, thiophenes, pyrazoles, isoxazoles, thiazoles, 1,2,3-triazoles, pyridazinones), implemented by introducing functional groups in the α-position to the carbonyl group with subsequent cyclocondensations (Hanch, Paal-Knorr, [4+2] and [3+2]-cyclization reactions) are reviewed. Beckman and Schmidt rearrangements in the chemistry of tetrahydroindolones are accompanied by a cycle expansion with the formation of lactams or their transformation products. The Fischer reaction allows to obtain polyheterocycles with a new indole ring at the same time as the Dimrot rearrangement allows to synthesize pyrroloquinolones. Among the ways of modifying side chains of tetrahydroindolone, the three-component Passerini reaction is the most promising one, which provides quick access to indolone-N-amino acid derivatives.

Extents of Reaction and Mass Transfer in the Analysis of Chemical Reaction Systems

Eddy diffusivities for the convective boundary layer derived from LES spectral data