Photoredox Synthesis of Silicon-Containing Isoindolin-1-ones and Deuterated Analogues Through Hydrosilylation and Deuterium-silylation.

An efficient, practical, and metal-free protocol for the synthesis of silicon-containing isoindolin-1-ones and deuterated analogues via the synergistic combination of an organic photoredox and hydrogen atom transfer process is described. This strategy features mild reaction conditions, high atom economy, and excellent functional group compatibility, delivering a myriad of structurally diverse and valuable products with good to excellent yields.

Photocatalytic synthesis of alkyl-alkyl sulfones via direct C(sp3)-H bond functionalization.

We report a highly efficient one-pot, three-component strategy for the construction of alkyl-alkyl sulfones through a photoinduced TBADT-catalyzed C(sp3)-H sulfonylation of unactivated hydrocarbon compounds. A wide range of commercially available hydrocarbon compounds and bioactive molecules can be successfully applied to the catalytic system, affording the corresponding alkyl-alkyl sulfones in good to excellent yields (>50 examples, up to 87% yield).

Photocatalytic Synthesis of Diarylmethyl Silanes via 1,6-Conjugate Addition of Silyl Radicals to p-Quinone Methides.

A novel photocatalytic method for the preparation of diarylmethyl silanes was reported through silyl radicals addition strategy to p-QMs (p-quinone methides). This protocol could tolerate a variety of functional groups affording the corresponding silylation products with moderate to excellent yields. The resulting silylation products could be easily converted into a series of bioactive GPR40 agonists and useful p-QMs precursors for the synthesis of compounds possessing both quaternary carbon centers and silicon substituents through simple operation. A plausible mechanism of silyl radicals to p-QMs was proposed on the basis of experimental results and previous literature.

Silylation and (Hetero)aryl/alkenylation of Unactivated Alkenes via Radical-Mediated Distal 1,4-Migration with Hydrosilanes under Organophotocatalysis.

We report a novel organic photoredox catalysis to achieve unprecedented γ-(hetero)aryl/alkenyl-δ-silyl aliphatic amines via silyl-mediated distal (hetero)aryl/alkenyl migration of aromatic/alkenyl amines bearing unactivated alkenes with hydrosilanes. This protocol features mild and metal-free reaction conditions, high atom economy, excellent selectivity, and functional group compatibility. Mechanistic studies suggest that silylation and (hetero)aryl/alkenylation involve photoredox hydrogen atom transfer catalysis and subsequent 1,4-migration of a remote (hetero)aryl/alkenyl group from nitrogen to carbon.

[Hyperspectral remote sensing image classification based on SVM optimized by clonal selection].

Model selection for support vector machine (SVM) involving kernel and the margin parameter values selection is usually time-consuming, impacts training efficiency of SVM model and final classification accuracies of SVM hyperspectral remote sensing image classifier greatly. Firstly, based on combinatorial optimization theory and cross-validation method, artificial immune clonal selection algorithm is introduced to the optimal selection of SVM (CSSVM) kernel parameter a and margin parameter C to improve the training efficiency of SVM model. Then an experiment of classifying AVIRIS in India Pine site of USA was performed for testing the novel CSSVM, as well as a traditional SVM classifier with general Grid Searching cross-validation method (GSSVM) for comparison. And then, evaluation indexes including SVM model training time, classification overall accuracy (OA) and Kappa index of both CSSVM and GSSVM were all analyzed quantitatively. It is demonstrated that OA of CSSVM on test samples and whole image are 85.1% and 81.58, the differences from that of GSSVM are both within 0.08% respectively; And Kappa indexes reach 0.8213 and 0.7728, the differences from that of GSSVM are both within 0.001; While the ratio of model training time of CSSVM and GSSVM is between 1/6 and 1/10. Therefore, CSSVM is fast and accurate algorithm for hyperspectral image classification and is superior to GSSVM.

[A method of hyperspectral quantificational identification of minerals based on infrared spectral artificial immune calculation].

Rapid identification of minerals based on near infrared (NIR) and shortwave infrared (SWIR) hyperspectra is vital to remote sensing mine exploration, remote sensing minerals mapping and field geological documentation of drill core, and have leaded to many identification methods including spectral angle mapping (SAM), spectral distance mapping (SDM), spectral feature fitting(SFF), linear spectral mixture model (LSMM), mathematical combination feature spectral linear inversion model(CFSLIM) etc. However, limitations of these methods affect their actual applications. The present paper firstly gives a unified minerals components spectral inversion (MCSI) model based on target sample spectrum and standard endmember spectral library evaluated by spectral similarity indexes. Then taking LSMM and SAM evaluation index for example, a specific formulation of unified MCSI model is presented in the form of a kind of combinatorial optimization. And then, an artificial immune colonial selection algorithm is used for solving minerals feature spectral linear inversion model optimization problem, which is named ICSFSLIM. Finally, an experiment was performed to use ICSFSLIM and CFSLIM to identify the contained minerals of 22 rock samples selected in Baogutu in Xinjiang China. The mean value of correctness and validness identification of ICSFSLIM are 34.22% and 54.08% respectively, which is better than that of CFSLIM 31.97% and 37.38%; the correctness and validness variance of ICSFSLIM are 0.11 and 0.13 smaller than that of CFSLIM, 0.15 and 0.25, indicating better identification stability.

Photoredox Metal-Free Synthesis of Unnatural ß-Silyl-α-Amino Acids via Hydrosilylation.

An efficient, practical and metal-free methodology for the synthesis of ß-silyl-α-amino acid motifs via photoredox and hydrogen atom transfer (HAT) process is described. This protocol enables the direct hydrosilylation of dehydroalanine derivatives and tolerates a wide array of functional groups and synthetic handles, leading to valuable ß-silyl-α-amino acids with moderate to good yields.

Photoredox Metal-Free Allylic Defluorinative Silylation of α-Trifluoromethylstyrenes with Hydrosilanes.

We report an efficient strategy that combines organic photoredox and hydrogen atom transfer to deliver gem-difluoroallylsilanes via defluorinative silylation of α-trifluoromethylstyrenes using hydrosilanes as silicon sources. This protocol provides an environmentally friendly approach for the preparation of structurally diverse gem-difluoroallylsilanes with excellent functional group compatibility and renders it suitable for late-stage modification of bioactive and complex molecules.

1,3-Bis(2-quinolylcarbon-yl)-1H,3H-2,1,3-benzothia-diazole 2-oxide.

In the title compound, C(26)H(16)N(4)O(3)S, the thia-diazole ring adopts an envelope conformation, with the S atom occupying the flap position. The dihedral angle between the two quinoline ring systems is 55.32 (8)°. In the crystal, the mol-ecules are linked into chains along [010] by C-H⋯O hydrogen bonds. The chains are connected via π-π inter-actions involving one of the pyridine rings [centroid-centroid distance = 3.5558 (18) Å].

N,N'-Bis(4-chloro-phen-yl)naphthalene-1,4-dicarboxamide N,N-dimethyl-formamide disolvate.

In the title compound, C(24)H(16)Cl(2)N(2)O(2)·2C(3)H(7)NO, the two C=O groups adopt an anti orientation. The two amide groups are twisted away from the naphthalene ring system by 59.10 (4) and 68.22 (4)°. The crystal packing is stabilized by N-H⋯O and C-H⋯O hydrogen bonds.

(E)-1-(4-Nitro-phen-yl)-3-phenyl-prop-2-en-1-one.

In the title compound, C(15)H(11)NO(3), the configuration of the keto group with respect to the olefinic double bond is s-cis. The two benzene rings form a dihedral angle of 5.00 (5)°. The mol-ecules are linked into a two-dimensional network parallel to (04) by C-H⋯O hydrogen bonds.

(E)-3-(4-Fluoro-phen-yl)-1-phenyl-2-propen-1-one.

In the title compound, C(15)H(11)FO, the configuration of the keto group with respect to the olefinic double bond is s-cis. The dihedral angle between the planes of the two benzene rings is 10.61 (10)°. The crystal packing is stabilized by C-H⋯π inter-actions involving both benzene rings.

(E)-1-(2-Nitro-ethen-yl)naphthalene.

The title mol-ecule, C(12)H(9)NO(2), adopts a trans configuration about the olefinic double bond. The dihedral angle between the naphthalene ring system (r.m.s. deviation = 0.012 Å) and the nitro-ethenyl group (r.m.s. deviation = 0.032 Å) is 12.66 (5)°. The mol-ecules are linked into a two-dimensional network parallel to the bc plane by C-H⋯O hydrogen bonds. The substituted benzene rings in adjacent networks are stacked with a centroid-centroid distance of 3.6337 (11) Å, indicating π-π inter-actions.

Bis{[1-(tert-butoxy-carbonyl)-pyrrolidin-2-yl]meth-yl} carbonate.

The asymmetric unit of the title compound, C(21)H(36)N(2)O(7), consists of two independent half-mol-ecules, the other halves being generated by twofold rotational axes. The two independent half-mol-ecules are related by a pseudo-inversion center. In one, the pyrrolidine ring adopts a twist conformation whereas in the other it is in an envelope conformation. The crystal packing is stabilized by C-H⋯O hydrogen bonds.

(E)-1-Nitro-4-(2-nitro-ethen-yl)benzene.

The asymmetric unit of the title compound, C(8)H(6)N(2)O(4), consists of two independent mol-ecules with similar geometries, each adopting a trans configuration about the olefinic double bond. The two mol-ecules are both almost planar (r.m.s. deviations = 0.034 and 0.035 Å) and form a dihedral angle of 83.62 (2)°. Short N⋯O contacts [2.834 (3)-2.861 (3) Å] are observed between the nitro groups of neighbouring mol-ecules, with the O atom located directly atop the p orbital of the N atom. In the crystal, the mol-ecules are linked into a three-dimensional network by the N⋯O inter-actions and by C-H⋯O hydrogen bonds.

N,N'-Bis(4-bromo-phen-yl)naphthalene-1,4-dicarboxamide N,N-dimethyl-acetamide disolvate.

The title compound, C(24)H(16)Br(2)N(2)O(2)·2C(4)H(9)NO, crystallizes in an anti C=O orientation. The two amide groups are twisted away from the naphthalene ring system by 62.67 (8) and 75.93 (7)°. The crystal packing is stabilized by N-H⋯O and C-H⋯O hydrogen bonds. Each of the dimethyl-acetamide solvent mol-ecules is disordered over two positions, with occupancy ratios of 0.556 (7):0.444 (7) and 0.654 (7):0.346 (7).

N,N'-Bis(4-methyl-phen-yl)naphthalene-1,4-dicarboxamide N,N-dimethyl-acetamide disolvate.

The title compound, C(26)H(22)N(2)O(2)·2C(4)H(9)NO, crystallizes in an anti C=O orientation. The two amide groups are approximately perpendicular to the naphthalene ring system [dihedral angles = 88.89 (1) and 89.08 (1)°]. Each of the dimethyl-acetamide solvent mol-ecules are disordered over two positions, with occupancies of 0.655 (12):0.345 (12) and 0.531 (13):0.469 (13). The crystal packing is stabilized by N-H⋯O and C-H⋯O hydrogen bonds.

2-Nitro-N-(8-quinolyl)benzamide.

In the title compound, C(16)H(11)N(3)O(3), the amide group is twisted away from the quinoline ring system and nitro-benzene ring by 8.02 (1)° and 54.92 (1)°, respectively. The crystal packing is stabilized by inter-molecular C-H⋯O hydrogen bonds, and π-π inter-actions between the quinoline ring systems of inversion-related mol-ecules, with a centroid-centroid distance of 3.4802 (13) Å.

3-Nitro-N-(8-quinol-yl)benzamide.

The title compound, C(16)H(11)N(3)O(3), crystallizes with two independent mol-ecules which are almost identical to each other in the asymmetric unit. The dihedral angle between the quinoline ring system and the nitro-benzene ring is 51.04 (9)° in one of the mol-ecules and 48.91 (9)° in the other. The crystal packing is stabilized by C-H⋯O hydrogen bonds and π-π inter-actions, with a centroid-centroid distance of 3.6010 (15) Å.

4-Nitro-N-(8-quinol-yl)benzamide.

In the title compound, C(16)H(11)N(3)O(3), the amide group is twisted away from the plane of the quinoline benzene ring by 3.93 (5)°, but is twisted away from the nitro-benzene ring by 22.68 (4)°. A weak intra-molecular C-H⋯O hydrogen bond is observed. In the crystal structure, mol-ecules are linked into a chain along the a axis by inter-molecular C-H⋯O hydrogen bonds.