Asymmetric Total Synthesis of Alstrostine G Utilizing a Catalytic Asymmetric Desymmetrization Strategy.

A highly effective enantioselective monobenzoylation of 1,3-diols has been developed for the synthesis of 1,1-disubstituted tetrahydro-ß-carbolines. The chemistry has been successfully applied to the asymmetric total synthesis of (+)-alstrostine G, which also features a cascade Heck/hemiamination reaction enabling facile construction of the pivotal pentacyclic core.

Concise Synthesis of (±)-Myrioneurinol Enabled by Sequential [2+2] Cycloaddition/Retro-Mannich Fragmentation/Mannich Reaction.

A concise total synthesis of (±)-myrioneurinol has been achieved in 14 steps. An efficient AgSbF6 /t-BuCl-catalyzed intramolecular [2+2] cycloaddition reaction of the alkynone-tethered enamine was developed to prepare the highly strained cyclobutene. It was used in combination with a subsequent retro-Mannich fragmentation/Mannich reaction to efficiently construct the tricyclic core of myrioneurinol.

Divergent Synthesis of Skeletally Distinct Arboridinine and Arborisidine.

A divergent synthesis of skeletally distinct arboridinine and arborisidine was achieved. The central divergent strategy was inspired by the divergent biosynthetic cyclization mode of arboridinine and arborisidine and their hidden topological connection. The branch point was reached through a Michael and Mannich cascade process. A site-selective intramolecular Mannich reaction was developed to construct the tetracyclic core of arboridinine, while a site-selective intramolecular α-amination of ketone was used to access the tetracyclic core of arborisidine. A strategic Peterson olefination through intramolecular nucleophile delivery was able to set up the exocyclic olefin of arboridinine.

[Application of microscopic spectroscopy in quality control of Niuhuang Qingxin pills].

Application of microscopic spectroscopy in quality control of Niuhuang Qingxin pills was discussed. First, microscopic characteristics specified by the statutory standard of Niuhuang Qingxin pills were summarized. Then new identification method was established for Dioscoreae Rhizoma, Saigae Tataricae Cornu, Cinnamomi Cortex and Saposhnikoviae Radix. Finally, microscopic spectroscopy was used for test of Dioscoreae Rhizoma's adulterant Dioscoreae Fordii Rhizoma.It was the first time for this technology being applied in adulteration test of Chinese patent medicine.The results showed that Saigae Tataricae Cornu was not detected in 2 batches of Niuhuang Qingxin pills from 1 manufacturer while Dioscoreae Fordii Rhizoma was detected in 3 batches of samples from 2 manufacturers. The proposed methods were accurate, simple, rapid, objective and economic, which offered a more comprehensive approach for quality control of Niuhuang Qingxin pills. It was indicated that conventional technology such as microscopic spectroscopy could play an important role in identification of traditional Chinese medicine whose index ingredient was deficient or tiny.

[Identication of pearl powder and conch powder from different origins by differential scanning calorimetry].

The paper is aimed to establish a methods for identication of pearl powder and conch powder from different origins. Hermetic aluminum pan was used to encapsulate samples. The optimal testing conditions were: heating rate 10 degrees C x min(-1), sample weight 3 mg and nitrogen gas flow rate 40 mL x min(-1). The enthalpy values of pearl powder and conch powder was obvious different. Identication of pearl powder and conch powder by DSC is a practical method for its accuracy, convenience and practificality.

High performance liquid chromatography characteristic spectrum of artificial musk.

OBJECTIVE: To determine the high performance liquid chromatography(HPLC)characteristic spectrum of artificial musk. METHODS: HPLC was performed on a HiQ Sil C18 analytical column(4.6 mm×250 mm)with the mobile phase of methanol/water(90:10 v/v);the detection wavelength was 254 nm and the column temperature was maintained at 25 ℃. The similarities among 10 batches of artificial musk samples were anlysised in accordance with the System for Evaluating the Similarities among the Chromatographic Fingerprints of Traditional Chinese Drugs,which is recommended by Chinese Pharmacopoeia Commission. RESULT: The similarities among these 10 batches of artificial musk ranged between 0.999 and 1.000. CONCLUSION: HPLC is a convenient,accurate and reliable technique for establishing the specific spectum of artificial musk and therefore can be used for the quality control of this product.

A Novel Method to Identify Three Quality Grades of Herbal Medicine Ophiopogonis Radix by Microscopic Quantification.

Maidong, the root tuber of Ophiopogon japonicus (Thunb.) Ker Gawl., is a commonly used herbal medicine in China. There are three quality grades of Maidong according to traditional opinion and modern research studies: superior quality (Zhe-Maidong), medium quality (Chuan-Maidong), and poorest quality (Chuan-Maidong with paclobutrazol, which is a kind of plant growth regulator). However, no efficient way to distinguish the three quality grades of Maidong exists; thus, the herbal markets and botanical pharmacies are flooded with Chuan-Maidong with paclobutrazol. To ensure the safety and quality of Maidong, a comparative microscopic study was performed on three quality grades of Maidong. The result was to establish a microscopic quantification method based on the area ratio between xylem and pith to distinguish the three quality grades of Maidong. Subsequently, Maidong from regional markets was evaluated by this method. In this study, we developed a novel quantification method to identify the three quality grades of Maidong, which could in turn make efforts on the quality improvement of Maidong. Our study is the first to demonstrate that microscopic technology could be used to distinguish different quality grades of a specific herbal medicine.

Distinguishing the Chinese materia medica Tiepishihu from similar Dendrobium species of the same genus using histological and microscopic method.

The Chinese Materia Medica, Tiepishihu, used as a tonic for over one thousand years, is a well-known precious medicine in China. According to the Chinese Pharmacopoeia, its source is the species Dendrobium officinale Kimura et Migo, which is distinguished from other species in Dendrobium genus. However, these species from the same genus are similar with Tiepishihu and caused confusion in the market. To find a quick and simple method to distinguish Tiepishihu from other similar species, histologic and microscopic methods were combined together to investigate the transverse section of stem of Tiepishihu and other similar species. Phloroglucinol test solution with hydrochloric acid was used to reveal the lignified tissue by staining the transverse section of Tiepishihu and similar species. Results revealed the unique identification characteristics to distinguish Tiepishihu from similar species, which were difficult to distinguish by other methods. The identification characteristics of Tiepishihu include the cells of vascular bundle sheath were stained red, parenchyma cells were not stained red. What's more, other species can be distinguished from each other with microscopic and histological characteristics. These characteristics proved stable and can be easily observed by normal light microscopic examination. This method is rapid, accurate, stable, and inexpensive.

Grief processing and deliberate grief avoidance: a prospective comparison of bereaved spouses and parents in the United States and the People's Republic of China.

In this study, the authors measured grief processing and deliberate grief avoidance and examined their relationship to adjustment at 4 and 18 months of bereavement for 2 types of losses (spouse, child) in 2 cultures (People's Republic of China, United States). Three hypotheses were compared: the traditional grief work assumption, a conditional grief work hypothesis, and a view of grief processing as a form of rumination absent among resilient individuals. Although cultural differences in grief processing and avoidance were observed, the factor structure of these measures proved invariant across cultures. Consistent with the grief work as rumination hypothesis, both grief processing and deliberate grief avoidance predicted poor long-term adjustment for U.S. participants. Furthermore, initial grief processing predicted later grief processing in both cultures. However, among the participants in the People's Republic of China, neither grief processing nor deliberate avoidance evidenced clear psychological consequences.