Pyrimidine series intermediates
Pyrimidine, also known as 1,3-diazepine, is a heterocyclic compound with the chemical formula C4H4N2. Pyrimidine is formed by replacing 2 carbons in the meta-position of benzene with 2 nitrogen atoms, and is a diazine. Like pyridine, pyrimidine retains its aromaticity.
Introduction
Name: Pyrimidine
Molecular formula: C4H4N2
Molar mass: 80.09 g/mol
Density: 1.016 g/ml
Melting point: 20 - 22 °C
Boiling point: 123 - 124 °C
CAS Number: 289-95-2
EINECS Number: 206-026-0
SMILES: C1=NC=NC=C1
Application
(1) Anticancer drugs. In the selection of anticancer substances, it is crucial that there are significant differences between tumor tissues and normal tissues, that is, they have a certain ability to recognize target cells. Porphyrin compounds have special affinity for cancer cells due to their unique structures, and they can selectively stay in cancer tissues. The research of it as a localizing agent and a drug for diagnosis and treatment of cancer has already aroused great interest of chemists, medical scientists and biologists. 5-Fluorouracil is a widely used anti-metabolite and anti-tumor drug in clinic. It has inhibitory effect on various tumors. It has good clinical effect in the treatment of colorectal cancer, gastric cancer, breast cancer and other cancers. Polyesters, polyester hydrocarbons, polyester amides, deoxyribonucleic acid, furans, 5-fluorouracil derivatives linked to nitroxide radicals all have antitumor effects.
(2) Anti-AIDS drugs. Viral diseases have become one of the most harmful diseases to human beings, especially the spread of AIDS, which has aroused widespread concern. There are many kinds of anti-AIDS drugs that have been approved by the US Food Administration (FDA), many of which are nucleoside compounds. In order to reduce the toxicity of drugs and improve their efficacy, scientists have begun to turn their attention to the study of non-nucleoside compounds, and such compounds have become the focus of antiviral drug research.
Synthetic method
Pyrimidines and various substituted pyrimidines are synthesized in a variety of ways. For example, barbituric acid (2,4,6-trihydroxypyrimidine) can be obtained by the condensation of urea and diethyl malonate under the action of sodium alkoxide. Barbituric acid and phosphorus oxychloride are heated together to obtain 2,4,6-trichloropyrimidine, which reacts with sodium methoxide to obtain trimethoxypyrimidine. Chloropyrimidines react with ammonia or primary and secondary amines to generate the corresponding aminopyrimidines. The derivatives of pyrimidine, cytosine, uracil and thymine, are the constituent parts of nucleic acid and deoxynucleic acid, and the pyrimidine part in the vitamin B1 molecule is a 4-amino-2-methyl-5-pyrimidine methyl group. Many oral long-acting sulfa drugs are derivatives of pyrimidine and its isomers.
The 2,4-dichloropyrimidine is prepared by reduction reaction in the presence of palladium, magnesium oxide and activated carbon.
Pyrimidine Series Intermediates,2-Chloro-5-Methylpyrimidine,5-Bromo-2-chloropyrimidine,2 4-Dichloro-5-Methylpyrimidine Fuxin Custchem Fine Chemical Co., Ltd. , https://www.custchemvip.com
Hygienic diaphragm valve introduction
Sanitary diaphragm valve is a special form of cut-off valve. Its opening and closing pieces is a piece of diaphragm made of soft material, the valve cavity and the valve cavity and drive components separated, it said the diaphragm valve. Diaphragm valve features are as follows: the most prominent feature is the diaphragm to the lower part of the valve body cavity and the upper valve cover cavity, so that located above the diaphragm stem, valve and other parts of the medium from corrosion, eliminating the need for packing seal structure, and No media leakage will occur. 1, the use of rubber or plastic, such as the production of the diaphragm seal, sealing better. As the diaphragm is wearing parts, depending on the characteristics of the media and regular replacement. 2, subject to diaphragm material, diaphragm valve for low pressure and temperature is not high occasions. 3, the diaphragm valve can be divided according to the structure of the form: house diaphragm valve, DC diaphragm valve, diaphragm valve cut-off, straight diaphragm valve, gate diaphragm valve and rectangular diaphragm valve; the connection is usually flanged (Quick connection); According to the drive can be divided into manual, electric and pneumatic three, of which pneumatic drive is divided into normally open, normally closed and reciprocating three. Sanitary diaphragm valve is the use of the valve stem to squeeze the elastomer film on the seat to cut off the gas circuit. Turn the hand wheel to move the valve stem up and down, so that the diaphragm leaves the valve seat to open the valve or press the diaphragm against the valve seat to close the valve. Such valves such as nitrile rubber diaphragm (silica membrane, EPDM, etc.) for pre-and pre-pumping pipe and the temperature of -25 ~ 80 ℃ non-corrosive gases. Such as the use of fluorine rubber diaphragm, can be used for high vacuum system, the use of temperature range -30 ~ 150 ℃. Search Keyword: More Valve Technical Articles