英语学习材料第20期

In the process of the total synthesis of chloramphenicol, reducing step selection stereoselectivity obtained reduction agent aluminum isopropoxide (+) threose type - on - Nitro phenyl 2 amino propylene glycol (amino). Then the induced crystallization method split, D (-) - threose amino compounds, finally get the chloramphenicol configuration for IR, 2R (-) d (-) threose type.

6) the structural characteristics of acid proof, anti - enzyme, broad-spectrum penicillin, and for example.

Answer: the side chain of the anti - acid penicillin are mostly electron withdrawing groups, such as non - and - resistant, - resistant, and the side chain of penicillin resistant, such as benzene, methyl - oxygen, etc..

7) why is it that the tetracycline antibiotics can not be used in foods such as milk and other foods rich in metal ions?

A: tetracycline drugs contain many hydroxyl groups, hydroxyl groups and carbonyl groups. In the near neutral condition, insoluble chelate can be formed with many kinds of metal ions. Therefore, tetracycline antibiotics can not be used with milk and other foods rich in metal ions.

Ninth chapter chemical treatment

1) quinolones can interfere with bone growth?

Answer: quinolone 3 carboxyl and four of the carbonyl can form complexes with metal ions, affecting calcium absorption, resulting in effects on bone growth. So this kind of drug instructions should not be marked, children under the age of 16 taking quinolone antibacterial drugs.

2) how to solve the adverse effects on the central of the quinolones?

Answer: quinolone antibacterial drugs toxic to the central is mainly by a piperazine moiety and GABA receptor binding induced. Therefore, we should in this part of the structural modification, the increase in the polarity of, drugs can not enter the blood brain barrier.

3) compared with ciprofloxacin norfloxacin synthesis route search, can draw those meaningful thoughts?

Answer: norfloxacin and ciprofloxacin in the structure difference is only one of the different substituents, but is completely using different synthetic routes, the diethyl sulfate can provide ethyl cation. But it is difficult to obtain cyclopropyl cation, so using different synthetic routes. In terms of bromination cyclopropane as electrophiles, due to instability in the SN2 nucleophilic

reaction in the formation of the transition state leading to the cyclopropane ring opening.

4) the research on the mechanism of the action of the drug is the contribution to the development of the chemical.

A: the mechanism of action of antibacterial drugs, the establishment of the theory of resistance to the development of chemical treatment of drugs to lay a solid foundation for the creation of basic theory of drug chemistry, its metabolism theory is still one of the important theory of drug design.

5) the general situation of the research on the anti malaria drugs, and the way and method to get the new drug from the structure of the natural medicine.

Answer: source of antimalarial drugs in natural products quinine through a series of anti malarial drugs on the modification of, especially from its discovery to the metabolic site. This site was closed to get better anti malarial drugs. In addition, the structure of the natural product can be simplified as well as the anti malaria drugs, such as artemisinin.

6) in the chemical treatment of drugs, the study of bacteria and fungi is ahead of the study of the virus, and how to further improve the speed of antiviral drugs

Answer: the role of antibacterial agents and antifungal agents are selected to the different bacteria and human cells metabolism, so the human body is relatively small. The virus is the use of the human body of the host cells, there is no way of its own metabolism. So the development speed is slow. The development of anti viral drugs depends on the difference between the virus and the human cells.

7) the relationship between the structure and activity of the drug from the perspective of anti - metabolism? Answer: sulfonamides as antimetabolites substitution of amino benzoic acid in bacteria of tetrahydrofolate synthesis, sulfa drugs in structure and electrical and p-aminobenzoic acid similar. If change the similarity, the antibacterial activity is decreased, and the similarity is maintained. The tenth chapter of the first generation and 1 generation of oral hypoglycemic agents in vivo metabolism of the first and second generation of oral hypoglycemic agents

A: the first generation of the degradation of the liver in the liver is a hydroxyl or carboxyl derivative and inactivated, mainly from the kidney.

The second generation is different from the first generation, which mainly consists of the oxidation of the lipid ring and the inactivation of the lipid.

2 starting from the structure of Spironolactone, the physical and chemical properties, metabolic characteristics and side effects of the body are described briefly.

Answer: Nature: insoluble in water, and sulfate appear red, and the smell of hydrogen sulfide,

and isoniazid in formic acid solution generate soluble yellow product, in formic acid and hydroxylamine hydrochloride, ferric chloride reaction to produce red complex

Metabolism: after oral administration of 70% immediately absorbed easily in liver metabolism, generation and canrenone canrenoic acid.

Disadvantages: the main side effects of hyperkalemia, anti androgen effect

Eleventh chapter hormones

1) cortisone and hydrocortisone have side effects? How to improve?

Answer: two have anti-inflammatory effects, can produce sodium retention of the side effect of potassium, causing swelling, which is the role of protein degradation caused by the reduction of body nitrogen and adrenal atrophy. These serious side effects affect the clinical application. So we hope to remove or reduce the side effects, and enhance the anti - inflammatory effect. Scientists were a lot of research, in cortisone and hydrocortisone molecular C1 or C2 position to introduce a double bond, respectively by prednisone and prednisolone. The anti-inflammatory effect of the two was increased by 3 to 4 times and the side effect was decreased. In the future, C16 is found in the C6 or the C9, the introduction of halogen, the introduction of hydroxyl or methyl group can enhance the anti-inflammatory effect and remove salt retention. For example 6. Methyl prednisolone, inflammation, and enhancing the role of liver glycogen is hydrogenated prednisone increased three fold; 6 alpha hydrogen fluoride throwing prednisone was increased by 3 ~ 4 times, and there is no sodium retention effect, suitable for long-term use. The effect of prednisone on fluorine hydrogenation on rheumatic arthritis and allergies are better than hydrocortisone, nor sodium retention effect. The acetonide acetate called triamcinolone acetonide, anti-inflammatory effect of hydrocortisone is 20 ~ 40 times, almost no sodium retention effect. Applies to rheumatoid arthritis, acute, and so on. In conclusion, the effect of anti - inflammation is improved, and the side effect of the structure is improved.

2) from the structure activity relationship, the role of the adrenal cortex hormone in the metabolism of glucose and electrolytes was explained. A: the physiological role of adrenal cortical hormone has a high structural specificity, the skeleton of the whole trans - type of activity is required. The structural characteristics of general 17- have a hydroxy methyl ketone, and has a 4-3- keto in ring A. In the 11- position, the cortical hormone is usually in the oxygen atom or in the ester ring (e.g., formaldehyde). And the glucocorticoid is a group of 17- (11-) with oxygen atom in the position of the group (a ketone group or a beta hydroxy group). The two type of action is not absolute, because of the most suitable and sub suitable for the receptor, it has a wide range of physiological functions, which can be strengthened or weakened by some groups. Therefore, the study on the structure activity relationship can be designed to reduce the side effects. Such as the C9 and C16 were replaced by fluoride and methyl group into dexamethasone and Batamison, not only a dozen times increase in the role of glucocorticoid metabolism, but almost completely eliminate the need for the salt of the corticosteroid side effects. The introduction of double bonds, only delta 1 enhanced activity, reduce side effects. Such as

prednisone and prednisolone activity of hydrocortisone 3 ~ 5 times. May be due to a delta 1 double bond to A ring due to changes in geometry. According to a report in the blood containing compounds of] 1 than hydrocortisone has a longer half-life. Because of its ring a part of metabolism is relatively slow. Through the above analysis, we can see that different groups are introduced into the framework of the adrenal cortex hormone, and have an effect on its activity, which affects the regulation of some metabolism.

3) scientists how to find more powerful oral progesterone? Answer: because of natural progesterone in the gastrointestinal tract is easy to damage and failure, invalid by oral administration, clinical can only for intramuscular injection. The world medical workers are on the pill research attaches great importance to in order to obtain long-lasting progesterone and progesterone made a structure activity relationship studies. Decrease in progesterone 17 alpha introducing hydroxyl, but the hydroxyl esterification effect is strong and lasting. And then the 6- position is introduced into the double bond, halogen or methyl group can enhance the role. Such as effectiveness 6 alpha methyl alpha - 17 hydroxy progesterone subcutaneous injection for 50 to 60 times of progesterone, and oral and medroxyprogesterone acetate, cyproterone, megestrol and hydroxyprogesterone caproate are powerful oral progesterone. Clinical and estrogen use as oral contraceptives.

4) in different parts of the male steroid, the introduction of different groups can enhance or decrease the activity of the androgen. For example, we should introduce the 3- or 3 - hydroxy group to enhance the activity of the male hormone. The 17 alpha position of the male has no effect on the activity of the androgen or the assimilation, and the 17 beta hydroxy is the strongest of the substituted group. 17 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -. It is considered that the 17 beta - oxygen atom is very important for the connection with the receptor site. 17 a-alkyl can prevent metabolic changes in this area, and therefore the compounds with oral activity. The introduction of the 17 alpha - position of the acetylene group showed that the activity of progesterone, such as pregnancy, was shown in the. In the 16 position of the introduction of large groups, it will produce an antagonistic effect, such as TSAA-291 is an anti androgen drugs. Danshion sterane ring expansion or shrinkage, generally the androgenic and assimilation weakened or destroyed. In a ring into a SP2 hybridized carbon atoms, the ring in a plane, so we can get a stronger assimilation, such as our Tan tebuconazole and hydroxy methylene dragon. The nature of matter is determined by the structure of the material.

5, the introduction of different groups of different parts of the male and the female nucleus can enhance or decrease the activity of the androgen.

A: according to the role of the drug in the structure of the drug is required to have the characteristics of 17- hydroxyl, it is envisaged in the appropriate position of the molecule to connect a large group, it will produce space, can affect the role of androgen. According to this design idea, a new kind of anti androgen drugs with little side effect was successfully synthesized. Such as TSAA-291 is one of the best anti androgen effects. Can be used for the treatment of prostate hypertrophy, hair and acne, etc..

6 estrogen and progesterone combined medication why can contraception

Answer: normal women's anterior pituitary secretion and promote