A Heterocyclic Compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s).[1] Heterocyclic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and applications of these heterocycles
Examples of heterocyclic compounds include all of the nucleic acids, the majority of drugs, most biomass (cellulose and related materials), and many natural and synthetic dyes.
Although heterocyclic compounds may be inorganic, most contain at least one carbon. While atoms that are neither carbon nor hydrogen are normally referred to in organic chemistry as heteroatoms, this is usually in comparison to the all-carbon backbone. But this does not prevent a compound such as borazine (which has no carbon atoms) from being labelled "heterocyclic". IUPAC recommends the Hantzsch-Widman nomenclature for naming heterocyclic compounds.
Heterocyclic Compound Heterocyclic Compound,Cas 49609-15-6 In Stock,2-Chloro-7-Methoxy-Quinoline,Cas 49609-15-6 2-Chloro-7-Methoxy-Quinoline Jinan Meigao Biopharmaceutical Technology Co., Ltd. , http://www.meigaobiopharma.com
From January to May 2009, China imported a total of 26,609 metal processing machine tools, a year-on-year decrease of 31.4%; the import value was 2.49 billion US dollars, a year-on-year decrease of 15.8%; the average import unit price was 93,731 US dollars / Taiwan, an increase of 24.6%.
From the above data, after the import volume fell by 52% in April, the import volume of metal processing machine tools in May fell by more than 50% year-on-year. However, the average import unit price is still rising, which indicates that China's metal processing machine tool imports are still mainly dominated by medium and high-end products.
According to analysis, the main reasons for the decline in machine tool imports are: the negative impact of the financial crisis on China's economy is still continuing, which has led to a sharp drop in demand for machine tool products in the domestic market; the cancellation of preferential policies for foreign-invested equipment has led to a reduction in import power, making China generally Trade methods and foreign-invested enterprises have become “one-up and one-off†in the import of machine tools and equipment. The quality and technical level of domestically produced machine tools have been greatly improved, and the independent innovation of enterprises has made breakthroughs, and the ability to innovate has been greatly improved. Play an important role.
China's metal processing machine tool imports fell another 50% in May
According to the latest statistics released by the customs, in May 2009, China imported 3,337 sets of metal processing machine tools, down 60.2% year-on-year and 23.9% month-on-month; the import value was 437 million US dollars, a year-on-year decrease of 33.6%, a decrease of 19.7% from the previous month; The unit price was US$130,954 per unit, an increase of 67% year-on-year and a 5.5% increase from the previous month.