[Energy-saving and Emission Reduction Path for Road Traffic in Key Coastal Cities of Guangdong, Fujian and Zhejiang].

The rapid development of society and economy has resulted in a substantial increase in energy consumption, consequently exacerbating pollution issues. Current research predominantly focuses on energy-saving and emission reduction in road transportation within individual cities or the three major economic regions of China:the Yangtze River Delta, the Pearl River Delta, and the Beijing-Tianjin-Hebei Region. However, there is a dearth of studies addressing the southeastern coastal economic region.

Divergent Synthesis of Highly Substituted Tetrahydroquinolines and Cyclopentenes via Lewis Base Catalyzed Switchable [4 + 2] and [3 + 2] Annulations of MBH-Carbonates with Activated Olefins.

A highly selective and divergent synthesis which enabled access to various complex compounds is highly attractive in organic synthesis and medicinal chemistry. Herein, we developed an effective method for divergent synthesis of highly substituted tetrahydroquinolines via Lewis base catalyzed switchable annulations of Morita-Baylis-Hillman carbonates with activated olefins. The reaction displayed switchable [4 + 2] or [3 + 2] annulations via catalyst or substrate control, providing a diverse range of architectures which contained highly substituted tetrahydroquinolines or cyclopentenes with three contiguous stereocenters bearing a quaternary carbon center in high yields with excellent diastereoselectivities and regioselectivities.

Highly regioselective synthesis of lactams cascade reaction of α,β-unsaturated ketones, ketoamides, and DBU as a catalyst.

Herein, the aldol/Michael cascade reaction on the β,γ-positions of α,β-unsaturated ketones with ketoamides to construct bicyclic lactams DBU catalysis has been developed. The substrates were well-tolerated with high regio- and diastereoselectivities in moderate to good yields (32 examples). The control experiments revealed that the hydrogen of the amide was the key factor.

[3 + 2] cycloaddition of nonstabilized azomethine ylides and 2-benzothiazolamines to access imidazolidine derivatives.

A simple and practical method for the construction of 1,3,5-trisubstituted imidazolidine derivatives [3 + 2] cycloaddition reaction has been developed. This reaction could smoothly proceed between nonstabilized azomethine ylides generated and 2-benzothiazolamines to deliver a wide scope of differently substituted imidazolidines in high yields (up to 98%). The structure of one example was confirmed by X-ray single-crystal structure analysis.

Substrate-Controlled Regioselectivity Switchable [3 + 2] Annulations To Access Spirooxindole Skeletons.

The additive-free [3 + 2] annulation from isatins, amino acids with 2-styrylbenzoxazoles, was described, providing a series of functional and structurally complex 3,3'-pyrrolidinyl-spirooxindole derivatives containing four contiguous and two quaternary stereogenic centers in high yields (up to 95%) and excellent diastereoselectivities (up to >25:1 dr). Interestingly, the reaction exhibits switchable regioselectivity depending on the substrate of amino acids. With proline or thioproline as the substrate, the reaction afforded α-regioselective spirooxindole skeletons.

A copper iodide-catalyzed coupling reaction of benzofuran-3(2H)-ones with amines: an approach to α-ketoamides.

A CuI-catalyzed coupling reaction of benzofuran-3(2H)-ones with amines has been well established for the direct synthesis of α-ketoamides. This process involves C-O bond cleavage and C[double bond, length as m-dash]O/C-N bond formation. Mechanism studies indicated that this α-ketoamide formation reaction may involve a free radical process.

Dearomative [3 + 2] cycloaddition reaction of nitrobenzothiophenes with nonstabilized azomethine ylides.

A highly diastereoselective dearomative [3 + 2] 1,3-dipolar cycloaddition reaction of nitrobenzothiophenes with an -generated nonstabilized azomethine ylides has been developed. The transformation provides a series of functionalized fused tricyclic benzo[4,5]thieno[2,3-]pyrroles in good yields (up to 92%) under mild reaction conditions. In addition, a gram-scale experiment and the synthetic transformation of the cycloadduct further highlighted the synthetic utility.

1,3-Dipolar cycloaddition of isatin ,'-cyclic azomethine imines with α,β-unsaturated aldehydes catalyzed by DBU in water.

A simple and green procedure was established by [3 + 3] cycloaddition reaction of isatin derived cyclic imine 1,3-dipoles with α,β-unsaturated aldehydes, giving the desired spiro heterocyclic oxindoles with aza-quaternary centers in good yields and diastereoselectivities. It should be noted that water can be employed as a suitable solvent for the improvement of diastereoselectivity.

Synthesis of γ-Lactones by TBAI-Promoted Intermolecular Carboesterification of Carboxylic Acids with Alkenes and Alcohols.

A novel tetrabutylammonium iodide (TBAI)-promoted three-component reaction of carboxylic acid with alkene and alcohol has been developed, which represents facile and straightforward access to polysubstituted γ-lactone skeletons in moderate-to-good yields. This methodology is distinguished by the use of a commercial catalyst and readily available starting materials, wide substrate scope, and operational simplicity. Mechanistic studies suggested that this transformation went through a radical process.

Cross 1,3-dipolar cycloadditions of C,N-cyclic azomethine imines with an N-benzyl azomethine ylide: facile access to fused tricyclic 1,2,4-hexahydrotriazines.

A cross 1,3-dipolar cycloaddition of two different ylides between C,N-cyclic azomethine imines with an in situ-generated nonstabilized azomethine ylide from an N-benzyl precursor was realized. The reactions afforded a clean and facile access to diverse fused tricyclic 1,2,4-hexahydrotriazines in high yields (up to 96%). The chemical structures of the typical compounds were confirmed by X-ray single-crystal structure analysis.

N-Heterocyclic Carbene/Lewis Acid Dual Catalysis for the Divergent Construction of Enantiopure Bridged Lactones and Fused Indenes.

The chiral triazole carbene and Ti(OPr-i) cocatalyzed reaction between α,β-unsaturated aldehydes and 2-(aroylvinyl)benzaldehydes was systematically studied. A divergence in reaction pathways was observed under different reaction conditions. In benzene solvent and at ambient temperature, the reaction produced 4,5-dihydro-1,4-methanobenzo[c]oxepin-3-ones, the bridged caprolactones, as the major products in moderate yields with excellent enantioselectivity.

The Reaction of 2-Aroylvinylcinnamaldehydes with Aromatic Aldehydes by Dual Catalysis with a Chiral N-Heterocyclic Carbene and a Lewis Acid: Enantioselective Construction of Tetrahydroindeno[1,2-c]furan-1-ones.

The cooperative chiral N-heterocyclic carbene and Lewis acid catalyzed reactions between 2-aroylvinylcinnamaldehydes and various aromatic aldehydes produced multifunctional tetrahydroindeno[1,2-c]furan-1-ones with excellent enantioselectivity. This work developed a versatile and efficient method for highly enantioselective construction of chiral tetrahydroindeno[1,2-c]furan-1-one, which are not easily prepared by other synthetic methods.

Chiral N-heterocyclic carbene/Lewis acid cooperative catalysis of the reaction of 2-aroylvinylcinnamaldehydes: a switch of the reaction pathway by Lewis acid activation.

The chiral N-heterocyclic carbene/Lewis acid co-catalyzed reaction of 2-aroylvinylcinnamaldehydes produced good yields of indeno[1,2-c]furan-1-one derivatives with excellent enantioselectivity and diastereoselectivity. A switch of intramolecular cyclization to intermolecular dimerization was achieved by the cooperative catalysis of chiral triazole carbene and Ti(OPr-i)4 catalysts.

N-Heterocyclic Carbene-Catalyzed Oxidative Annulations of α,β-Unsaturated Aldehydes with Hydrazones: Selective Synthesis of Optically Active 4,5-Dihydropyridazin-3-ones and Pyridazin-3-ones.

A novel and efficient method for the highly enantioselective synthesis of chiral 4,5-dihydropyridazin-3-one derivatives has been developed based on the chiral N-heterocyclic carbene-catalyzed oxidative annulation between α,β-unsaturated aldehydes and hydrazones. Meanwhile, the selective synthesis of either 4,5-dihydropyridazin-3-ones or pyridazin-3-one derivatives from the same reactants has been achieved by simply varying catalytic and reaction conditions.

N-heterocyclic carbene-catalyzed diastereoselective and enantioselective reaction of 2-aroylvinylcinnamaldehydes with α,β-unsaturated imines: complete control and switch of diastereoselectivity by N-substituents of catalysts.

Highly diastereoselective and enantioselective reactions between 2-aroylvinylcinnamaldehydes and α,β-unsaturated imines were achieved under asymmetric catalysis of chiral triazole carbene catalysts. In the presence of N-anisylindeno[2,1-b]triazolo[4,3-d][1,4]oxazinium salt, the reaction of 2-aroylvinylcinnamaldehydes with α,β-unsaturated imines afforded indeno[2,1-c]pyran-1-one derivatives 4 with 90%-99% ee, while enantiopure indenocyclopentan-1-ones 5 (>99% ee) were obtained under the catalysis of N-mesitylindeno[2,1-b]triazolo[4,3-d][1,4]oxazinium salt. A slight variation of an N-substituent on triazole carbenes was found to switch completely the diastereoselectivity of the reaction for the formation of indeno[2,1-c]pyran-1-ones.

Palladium-catalyzed Suzuki-Miyaura coupling of aryl sulfamates with arylboronic acids.

Readily available NHC-Pd(II)-Mp complexes 2 showed efficient catalytic activity toward the Suzuki-Miyaura coupling of aryl sulfamates with arylboronic acids or potassium phenyltrifluoroborate, giving the expected coupling products in good to high yields. It should be noted that this is the first example so far of the phosphine-free, NHC-Pd(II) complexes catalyzed Suzuki-Miyaura coupling of aryl sulfamates with arylboronic acids.

Quantitative detection of Streptococcus mutans and bacteria of dental caries and no caries groups in permanent teeth from a north China population.

Background: Streptococcus mutans (S. mutans) is the prime pathogen of dental caries. There are few reports that studied the relationship between S.

N-heterocyclic carbene-palladium(II)-1-methylimidazole complex-catalyzed Suzuki-Miyaura coupling of aryl sulfonates with arylboronic acids.

A well-defined NHC-Pd(II)-Im complex 1 was found to be an effective catalyst for the Suzuki-Miyaura coupling of aryl sulfonates including tosylates and phenylsulfonates with arylboronic acids, giving the desired coupling products in good to high yields. Acceptable yields can also be achieved even by using the less reactive mesylates as the substrates. It is worthy of noting here that this is the first example of NHC-Pd(II) complex-catalyzed Suzuki-Miyaura coupling of aryl sulfonates with arylboronic acids, enriching an inexpensive, convenient, and alternative method for the synthesis of biaryl compounds.

[A family associated outbreak of Mycoplasma pneumoniae infection in a hospital ward].

Objective: To describe the epidemiological and serological features on a family associated outbreak caused by Mycoplasma pneumoniae (MP) infection occurred in Beijing in August 2007.

Methods: Mutual exposure of the family members was investigated and retrospective medical record was reviewed for the hospitalized patients. Serum antibodies to MP were measured and chest X-rays were taken for all the family members.

[Quantitative detection of Streptococcus mutans in different people with dental caries by real-time polymerase chain reaction].

Objective: To establish a quantity detection method of Streptococcus mutans (Sm) and bacteria and compare the relationship between the number of these bacteria and the prevalence of dental caries in different people.

Methods: With specific primers for a unique sequence in a 14 kb HaeIII restriction fragment consistently presenting during detecting Sm by chromosomal DNA fingerprints, the total number of Sm and bacteria of 99 saliva samples were detected by real-time polymerase chain reaction (PCR) and statistically analyzed.

Results: The primers were specific for Sm and the minimum detectable level by real-time PCR was 0.

Molecular prenatal diagnosis of alpha-thalassemia using real-time and multiplex polymerase chain reaction methods.

Molecular analysis of two fetuses at high risk of alpha-thalassemia (alpha-thal), and their family members, was performed using real-time polymerase chain reaction (PCR) with SYBR Green 1 (SYBR-PCR) dye combined with dissociation curve analysis and multiplex PCR (m-PCR) and DNA sequencing techniques. The genotype of the fetus from one family was --SEA/--SEA (Southeast Asian deletion), which produces hydrops fetalis syndrome. The genotype of the parents was --SEA/alphaalpha.

[Prenatal diagnosis for fetus with hemophilia A].

Objective: To study the prenatal genetic diagnostic methods for hemophilia A fetus.

Methods: From 2002 to 2006, 19 hemophilia A families were diagnosed either by long distance-polymerase chain reaction (LD-PCR) for factor VIII intron 22 inversion or by the DNA polymorphism genetic linkage analysis of factor VIII in the Beijing Chaoyang Hospital.

Results: (1) Totally 19 women, with 22 pregnancies received the prenatal diagnosis of fetal hemophilia A.

[Rapid diagnosis of Down's syndrome by multiplex real-time fluorescence relative quantitative PCR].

To establish a multiplex real-time fluorescence relative quantitative PCR method for diagnosis of Down's syndrome. The fragment from Down's syndrome critical region gene 3 (DSCR3) on chromosome 21 was used as the target gene, and the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene on chromosome 12 was used as the control gene. The two genes were amplified in the same tube.

[Improvement of gene analysis method in hemophilia A and its application of prenatal diagnosis].

Objective: To establish a simple and rapid system for carrier detection and prenatal diagnosis in hemophilia A (CHA) family.

Methods: Long distance-polymerase chain reaction (LD-PCR) was selected for detection factor VIII intron 22 inversion. Polymorphism of factor VIII intragenic restriction fragment length polymorphism (RFLP) of Xba I and Hin d III, short tandem repeat (STR) within intron 13 and 22, as well as extragenic DXS52 (ST 14) variable number of tandem repeat (VNTR) were assayed by PCR and linkage analysis.