Cyclopropane structure. The meaning of the word cyclopropane in the reference book of medicines

In a cyclopropane molecule, all carbon atoms are located in the same plane.

With this arrangement of carbon atoms in the cycle, the bond angles should be equal to 60 0, and the magnitude of their deviation from the normal bond angle (109 0 28) should be: α = (109 0 28 – 60 0): 2 = 24 0 44. This is the most intense cyclic system.

However, in reality, the bond angles between carbon atoms in the cyclopropane ring are 106 0. This is explained by the fact that σ bonds between carbon atoms in cyclopropane differ from ordinary σ bonds formed when sp 3 hybrid orbitals overlap in alkanes.

When carbon-carbon bonds are formed in the cyclopropane ring, only partial overlap of sp 3 -hybrid orbitals occurs, directed not along the straight line connecting the centers of bonded carbon atoms, but outside the cyclopropane plane, which leads to the formation of bent orbitals or so-called banana or τ- (Greek “tau”) bonds.

The formation of banana (or τ-) bonds in cyclopropane leads to a decrease in the angular stress in the cycle, since the angle between the axes of two electron clouds increases from 60 0 to 106 0, and the τ-bonds themselves become partially unsaturated and occupy an intermediate position in strength between σ- and π-bonds.

This explains the tendency of cyclopropane to undergo addition reactions. The partially unsaturated nature of the carbon atoms in the cyclopropane molecule is also evidenced by the increased proton mobility of hydrogen atoms.

Structure of cyclobutane and cyclopentane

In cyclobutane and especially in cyclopentane, the angular stress associated with the deviation of the bond angles of carbon atoms from the normal bond angle (109 0 28) is significantly lower.

When all carbon atoms of four- and five-membered rings are located in the same plane, the deviation of bond angles is respectively:

For cyclobutane - (109 0 28 - 90 0) : 2 = 9 0 44

For cyclopentane - (109 0 28 - 108 0) : 2 = 0 0 44

However, in reality, the molecules of cyclobutane and cyclopentane are not flat, since in flat structures all hydrogen atoms are in an obscured state, which leads to the appearance of torsional stress and a decrease in the stability of the molecules.

To reduce torsional stress, the molecules of cyclobutane and cyclopentane adopt non-planar conformations in which, due to the repulsive forces between hydrogen atoms, one of the carbon atoms in cyclobutane or two carbon atoms in cyclopentane continuously move out of the plane of the cycles.

Therefore, the rings of cyclobutane and cyclopentane seem to be in constant wave-like motion, during which a rapid transformation of one conformation into another occurs:

For cyclobutane:

For cyclopentane:

In the “chair” conformation, 6 hydrogen atoms are perpendicular to the average plane of the ring and are called axial (a-), and 6 others are close to this conditional plane and are called equatorial (e-). If one of the hydrogens is replaced by an alkyl or some functional group, it can be in an equatorial or axial position. At room temperature there is a single cyclohexane, rather than two isomers. The reason for this is the rapid inversion of the cycle, as a result of which the methyl group becomes equatorial from axial.

Rice. 16.3. Methylcyclohexane inversion

According to Bayer, cyclopentane has virtually no angular stress. However, even it does not exist in planar form, because in a flat molecule, all hydrogen atoms will be in an eclipsed conformation, which will lead to noticeable torsional stress. It is energetically more favorable for cyclopentane to exist in the form of a so-called “envelope”, in which 4 carbon atoms are in one plane, and the fifth comes out of it.

Rice. 16.4. Conformational changes of cyclopentane

Cyclobutane is also non-planar; it consists of two equilateral triangles connected along one side and located in different planes. The reason for the exit of two carbon atoms from the plane is still in the same obscured conformation of methylene groups, which is energetically unfavorable.

Rice. 16.5. Conformational changes of cyclobutane

In cyclopropane, carbon atoms cannot be in different planes (the geometric location of three points is a plane). The molecule can be represented as regular triangle. However, experimental data show that cyclopropane behaves as if the angle between C-C connections was 102 o. It is impossible to imagine a regular triangle with internal corners not equal to 60 o.

The overlap of atomic hybridized orbitals in the cyclopropane molecule is shown in Fig. 16.6. As you can see, the bond is not formed along the line connecting the centers of the atoms. Such bonds are called “banana” or curved. According to their characteristics, they occupy an intermediate position between s- and p-bonds. This fact explains the partial unsaturation of cyclopropane.

Rice. 16.6. Overlapping atomic orbitals in a cyclopropane molecule

As a result, in the molecules of cyclobutane and cyclopentane, the “overshadowing” of hydrogen atoms at neighboring carbon atoms decreases, which leads to a decrease in torsional stress due to the appearance of a small angular (angular) stress.

Orange steel cylinders with a volume of 1 l and 2 l under a pressure of 5 atm. The inscription is written in black.

Pharmacological action

General anesthetic , a means for inhalation anesthesia .

Pharmacodynamics and pharmacokinetics

Pharmacodynamics

Cyclopropane is a colorless gas with high analgesic and anesthetic activity.

Chemical properties

Cyclopropane is a representative of hydrocarbons with closed chains. Structural formula Cyclopropane:

When carbon atoms are closed into a ring, the severity of the narcotic effect increases significantly. And the proof of this is the great toxicity cyclopropane (and also cyclohexane , cyclopentane ) compared to methane hydrocarbons. The cyclopropane molecule contains weak bonds and is characterized by addition reactions. For example, the interaction between Cyclopropane and HBr. Below is the chain Cyclopropane - 1-bromopropane:

Cyclopropane has a pronounced narcotic effect (7 times stronger than nitrous oxide). Inhalation of 10% of its mixture with oxygen causes the surgical stage of anesthesia. There is a rapid induction of anesthesia and rapid awakening. The anesthesia is well controlled.

Also renders muscle relaxant effect . At the same time, it does not irritate the mucous membranes, does not have a toxic effect on the liver, and slightly reduces . It has a pronounced vagotropic effect, therefore for prevention bradycardia must be entered .

During anesthesia, short-term hyperglycemia occurs, which is not as pronounced as when using ether. In this connection, it can be used when , respiratory diseases And parenchymal organs . However, anesthesia with its use has not found widespread use due to respiratory depression, development arterial hypotension .

Possesses cardiotoxic effect - increases the sensitivity of the myocardium to (norepinephrine ) and when used in combination causes pronounced , development various violations rhythm and ventricular fibrillation.

Its mixtures with nitrous oxide And oxygen may explode in the presence of an electric spark. Currently rarely used.

Pharmacokinetics

Introduction to anesthesia - 3-5 minutes, without excitation stage. Quickly induces a stage of deep anesthesia.

It is not destroyed in the body and is excreted almost completely unchanged within 10 minutes.

Indications for use

introductory and basic during obstetric and gynecological operations in combination with oxygen , other anesthetics and muscle relaxants ;
short-term interventions for “minor” operations;
operations in old age.

Contraindications

Diseases accompanied disturbance of atrioventricular conduction .

Side effects

Headache, vomiting in the postoperative period, and intestinal paresis are common.

Instructions for use (Method and dosage)

Use only in mixture with oxygen in various systems (closed and semi-closed, less often semi-open) of anesthesia machines with dosimeters.

Inhalation of this agent at a concentration of 20-30 vol.% causes deep anesthesia . To maintain anesthesia, 15 vol.% is sufficient. Inhaling it through an anesthesia mask does not cause discomfort. Patients fall asleep without arousal. Oxygen is supplied continuously, and for another 5 min. after stopping the anesthesia.

To reduce the negative effects of this anesthetic and achieve optimal pain relief, a mixture is used: - part 1, cyclopropane - 0.4 parts, oxygen — 2 parts, which is served in a semi-closed manner after induction of anesthesia thiopental sodium . To avoid hypoxia, oxygen supply is stopped last. The use of such a mixture reduces post-anesthesia complications. Due to the rapid awakening, even before the end of the operation, analgesic .

-32.86 °C T. svspl. 555 °C Kr. dot 397,80 Chemical properties Solubility in water 0.502 g/100 ml Classification Reg. CAS number 75-19-4 PubChem 6351 SMILES Safety Toxicity slightly toxic, has narcotic properties NFPA 704 Data are based on standard conditions (25 °C, 100 kPa) unless otherwise stated.

Cyclopropane (trimethylene) - chemical compound with the formula C 3 H 6, the simplest hydrocarbon of the alicyclic (carbocyclic) series; belongs to cycloalkanes and is their first member of the homologous series.

Physical properties

A colorless flammable gas with a characteristic odor reminiscent of petroleum ether and a pungent taste. Relative density 1.879. At a temperature of 4 - 20 °C and a pressure of 5 atm it turns into liquid state; melting point −127 °C, boiling point of cyclopropane at atmospheric pressure −33 °C. Slightly soluble in water (one volume of gas at + 20 °C is soluble in 2.85 volumes of water). Easily soluble in alcohol, petroleum ether, chloroform and fatty oils. Highly flammable, mixtures with air, oxygen or nitrous oxide are explosive.

Cyclopropane has a stimulating effect on the body's cholinoreactive systems and causes a slight slowdown in the pulse, and arrhythmias are possible. Under the influence of cyclopropane, the sensitivity of the myocardium to adrenaline greatly increases; administration of epinephrine during cyclopropane anesthesia can cause ventricular fibrillation.

Cyclopropane anesthesia can be used for short-term surgical interventions.

Cyclopropane is used in a mixture with oxygen in a closed and semi-closed system (sometimes semi-open) using anesthesia machines with dosimeters. To maintain anesthesia, 15-18% cyclopropane is used. Induction of anesthesia is carried out with higher concentrations of cyclopropane. By the time the operation is completed, the supply of cyclopropane is stopped, and after 2 - 5 minutes. inhalation pure oxygen the patients wake up.

The oxygen supply must be continuous. It is necessary to ensure that sufficient ventilation of the lungs is maintained and the body is freed from carbon dioxide.

Cyclopropane is sometimes used as part of the Shane Ashman mixture. After induction of intravenous anesthesia with sodium thiopental, a mixture of gases is supplied (using a semi-closed method) in the following ratio: nitrous oxide - 1 part, oxygen - 2 parts, cyclopropane - 0.4 parts.

When using this mixture, after the end of anesthesia, it is necessary to exclude the narcotic components in a certain sequence (to avoid the development of hypoxia): first stop the supply of cyclopropane, after 2 - 3 minutes - nitrous oxide and after the same period - oxygen.

With the correct dosage of cyclopropane, anesthesia proceeds without complications, patients quickly wake up after the end of inhalation. In case of overdose, respiratory arrest and cardiac depression may occur, including cardiac arrest.

Due to the rapid awakening after cessation of anesthesia, patients may experience severe pain after surgery, so it is recommended to administer an analgesic before the end of the operation. After anesthesia, headache is relatively common, and in some cases, postoperative vomiting and intestinal paresis. Therefore, patients after awakening from anesthesia need careful monitoring.

Only medical personnel who have undergone appropriate training are allowed to use cyclopropane.

Contraindications

During cyclopropane anesthesia, the administration of adrenaline and norepinephrine is contraindicated.

Toxic effects of cyclopropane

When inhaling cyclopropane at a concentration of 15-20% and a mixture with oxygen in rats, after an hour the amount of glycogen and total proteins in the liver decreases, the activity of SH groups of liver cells increases and the content of ribonucleic acid in them increases. With chronic exposure to cyclopropane, bone marrow production, mainly granulocytes, is inhibited.

Release form

Release form: in seamless steel cylinders with a capacity of 1 and 2 liters of liquid cyclopropane under a pressure of 5 atm; the cylinders are painted orange and have the inscription<Осторожно. Циклопропан. Огнеопасен>.

Storage

Storage: in a cool place away from sources of fire.

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Notes



Alkanes

Alkenes

Alkynes

Dienes

Other unsaturated

Cycloalkanes

Aromatic

Polycyclic

Excerpt characterizing Cyclopropane

Princess Marya was left alone. She did not fulfill Lisa’s wishes and not only did not change her hairstyle, but also did not look at herself in the mirror. She, powerlessly lowering her eyes and hands, sat silently and thought. She imagined a husband, a man, a strong, dominant and incomprehensibly attractive creature, suddenly transporting her into his own, completely different, happy world. Her child, the same as she had seen yesterday with the nurse’s daughter, appeared to her at her own breast. The husband stands and looks tenderly at her and the child. “But no, this is impossible: I’m too bad,” she thought.
- Please come to tea. The prince will come out now,” the maid’s voice said from behind the door.
She woke up and was horrified by what she was thinking. And before going down, she stood up, entered the image and, looking at the black face of the large image of the Savior illuminated by the lamp, stood in front of it with her hands folded for several minutes. There was a painful doubt in the soul of Princess Marya. Is the joy of love, earthly love for a man possible for her? In her thoughts about marriage, Princess Mary dreamed of family happiness and children, but her main, strongest and hidden dream was earthly love. The feeling was the stronger the more she tried to hide it from others and even from herself. “My God,” she said, “how can I suppress these thoughts of the devil in my heart? How can I renounce evil thoughts forever, so that I can calmly fulfill Your will? And as soon as she made this question, God already answered her in her own heart: “Do not desire anything for yourself; don't search, don't worry, don't envy. The future of people and your destiny should be unknown to you; but live in such a way that you are ready for anything. If God pleases to test you in the responsibilities of marriage, be ready to do His will.” With this calming thought (but still with the hope of fulfilling her forbidden, earthly dream), Princess Marya, sighing, crossed herself and went downstairs, not thinking about her dress, or her hairstyle, or how she would enter and what she would say. What could all this mean in comparison with the predestination of God, without whose will not a single hair will fall from a human head?

When Princess Marya entered the room, Prince Vasily and his son were already in the living room, talking with the little princess and m lle Bourienne. When she entered with her heavy gait, stepping on her heels, the men and m lle Bourienne rose up, and the little princess, pointing at her to the men, said: Voila Marie! [Here is Marie!] Princess Marya saw everyone and saw them in detail. She saw the face of Prince Vasily, who stopped seriously for a moment at the sight of the princess and immediately smiled, and the face of the little princess, who read with curiosity on the faces of the guests the impression that Marie would make on them. She also saw M lle Bourienne with her ribbon and beautiful face and her gaze, more animated than ever, fixed on him; but she could not see him, she only saw something large, bright and beautiful, moving towards her when she entered the room. First, Prince Vasily approached her, and she kissed the bald head bending over her hand, and answered his words that she, on the contrary, remembered him very well. Then Anatole approached her. She still hasn't seen him. She only felt a gentle hand take her firmly and lightly touched her white forehead, above which her beautiful brown hair was anointed. When she looked at him, his beauty struck her. Anatopia with his thumb right hand by the buttoned button of his uniform, with his chest arched forward and his back arched back, shaking one outstretched leg and slightly bowing his head, silently, cheerfully looking at the princess, apparently not thinking about her at all. Anatole was not resourceful, not quick and not eloquent in conversations, but he had the ability of calm and unchangeable confidence, precious for the world. If a person who is not self-confident is silent at the first acquaintance and shows an awareness of the indecency of this silence and a desire to find something, and it will not be good; but Anatole was silent, shaking his leg, cheerfully observing the princess’s hairstyle. It was clear that he could remain silent so calmly for a very long time. “If anyone is uncomfortable with this silence, then talk, but I don’t want to,” his appearance seemed to say. In addition, in dealing with women, Anatole had that manner that most of all inspires curiosity, fear and even love in women - a manner of contemptuous consciousness of his superiority. It was as if he was telling them with his appearance: “I know you, I know you, but why bother with you? And you would be glad!” It may be that he did not think this when meeting women (and it is even likely that he did not, because he did not think much at all), but that was his appearance and such a manner. The princess felt this and, as if wanting to show him that she did not dare think about keeping him busy, turned to the old prince. The conversation was general and lively, thanks to the little voice and the sponge with a mustache that rose above the white teeth of the little princess. She met Prince Vasily with that method of joking, which is often used by talkatively cheerful people and which consists in the fact that some long-established jokes and funny, partly not known to everyone, funny memories are assumed between the person who is being treated like that and oneself, then as there are no such memories, just as there were none between the little princess and Prince Vasily. Prince Vasily willingly succumbed to this tone; The little princess involved Anatole, whom she hardly knew, in this memory of funny incidents that had never happened. M lle Bourienne also shared these common memories, and even Princess Marya felt with pleasure that she was drawn into this cheerful memory.
“At least now we’ll make full use of you, dear prince,” said the little princess, in French, of course, to Prince Vasily, “it’s not like at our evenings at Annette’s, where you always run away; remember cette chere Annette? [dear Annette?]
- Oh, you can’t talk to me about politics like Annette!
– What about our tea table?
- Oh, yes!
- Why have you never been to Annette? – the little princess asked Anatole. “And I know, I know,” she said with a wink, “your brother Ippolit told me about your affairs.” - ABOUT! “She shook her finger at him. - Even in Paris I know your pranks!
- And he, Hippolytus, didn’t tell you? - said Prince Vasily (turning to his son and grabbing the princess by the hand, as if she wanted to run away, and he barely had time to hold her), - but he didn’t tell you how he himself, Hippolyte, wasted away for the dear princess and how she le mettait a la porte? [kicked him out of the house?]
- Oh! C "est la perle des femmes, princesse! [Ah! this is the pearl of women, princesse!] - he turned to the princess.
For her part, m lle Bourienne did not miss the opportunity, when she heard the word Paris, to also enter into a general conversation of memories. She allowed herself to ask how long ago Anatole left Paris, and how he liked this city. Anatole very willingly answered the Frenchwoman and, smiling, looking at her, talked to her about her fatherland. Having seen the pretty Bourienne, Anatole decided that here, in Bald Mountains, it would not be boring. “Very pretty! - he thought, looking at her, - this demoiselle de compagn is very pretty. [companion.] I hope she will take it with her when she marries me,” he thought, “la petite est gentille.” [little one is cute.]

Cyclopropane

CYCLOPANUM (Cyclopropanum).

Synonym: Cyclopropane.

A colorless flammable gas with a characteristic odor reminiscent of petroleum ether and a pungent taste. Relative density 1.879. At a temperature of 4 - 20 C and a pressure of 5 atm it turns into a liquid state; The boiling point of cyclopropane at atmospheric pressure is 347 C. It is slightly soluble in water (one volume of gas at + 20 C is soluble in 2.85 volumes of water). Easily soluble in alcohol, petroleum ether, chloroform and fatty oils.

Cyclopropane has a strong general analgesic effect. Extremely flammable; its mixtures with oxygen, nitrous oxide and air may explode if in contact with flame, electrical spark and other sources that can cause ignition. When using cyclopropane, it is necessary to take all measures to prevent the possibility of an explosion, including precautions related to the use of electrical and X-ray equipment and to prevent the formation static electricity. Due to these features, as well as the advent of new methods and means of general anesthesia, cyclopropane is now extremely rarely used as an anesthetic. Cyclopropane acts quickly. At a concentration of 4 vol. % causes analgesia, 6 vol. % - turns off consciousness, 8 - 10 vol. % - causes anesthesia (stage III), in a concentration of 20 -30 vol. % - deep anesthesia.

In the body, cyclopropane is not destroyed and is released unchanged almost completely 10 minutes after stopping inhalation.

Cyclopropane does not have a pronounced effect on the functions of the liver and kidneys; slightly reduces diuresis. Sometimes, during anesthesia with cyclopropane, short-term hyperglycemia occurs, associated with excitation of adrenoreactive systems. This effect is less pronounced than when using ether.

Cyclopropane has a stimulating effect on the body's cholinoreactive systems and causes a slight slowdown in the pulse, and arrhythmias are possible. Under the influence of cyclopropane, the sensitivity of the myocardium to adrenaline greatly increases; administration of adrenaline during cyclopropane anesthesia can cause ventricular fibrillation.

Blood pressure increases slightly during anesthesia, which can lead to some increased bleeding.

Cyclopropane is used for introductory and basic anesthesia (cyclopropane with oxygen); It is often used in combination with other anesthetics (nitrous oxide, ether) and muscle relaxants. Indicated for patients with lung diseases, as it does not cause irritation of the mucous membranes of the respiratory tract. It can be prescribed for liver diseases and diabetes.

Cyclopropane anesthesia can be used for short-term surgical interventions.

The oxygen supply must be continuous. It is necessary to ensure that sufficient ventilation of the lungs is maintained and the body is freed from carbon dioxide.

Sometimes cyclopropane is used as a component. After induction of intravenous anesthesia with sodium thiopental, a mixture of gases is supplied (using a semi-closed method) in the following ratio: nitrous oxide - 1 part, oxygen - 2 parts, cyclopropane - 0.4 parts.

During cyclopropane anesthesia, the administration of adrenaline and norepinephrine is contraindicated.

Release form: in seamless steel cylinders with a capacity of 1 and 2 liters of liquid cyclopropane under a pressure of 5 atm; the cylinders are painted orange and have an inscription.

Only medical personnel who have undergone appropriate training are allowed to use cyclopropane.

Storage: in a cool place away from sources of fire.

Directory of medicines. 2012





General
Chem. formula	C3H6
Physical properties
State	colorless gas with a specific oil odor
Molar mass	42.0797 ± 0.0028 g/mol
Density	1.879 g/l (at normal conditions)
Thermal properties
T. float.	-127.62 °C
T. kip.	-32.86 °C
T. svspl.	555 °C
Kr. dot	397,80
Chemical properties
Solubility in water	0.502 g/100 ml
Classification
Reg. CAS number	75-19-4
PubChem
Reg. EINECS number	200-847-8
SMILES
InChI
ChEBI
ChemSpider
Safety
Toxicity	slightly toxic, has narcotic properties
NFPA 704
Data are based on standard conditions (25 °C, 100 kPa) unless otherwise stated.

Physical properties

A colorless flammable gas with a characteristic odor reminiscent of petroleum ether and a pungent taste. Relative density 1.879. At a temperature of 4 - 20 °C and a pressure of 5 atm it turns into a liquid state; melting point −127 °C, boiling point of cyclopropane at atmospheric pressure −33 °C. Slightly soluble in water (one volume of gas at + 20 °C is soluble in 2.85 volumes of water). Easily soluble in alcohol, petroleum ether, chloroform and fatty oils. Highly flammable, mixtures with air, oxygen or nitrous oxide are explosive.

Cyclopropane anesthesia can be used for short-term surgical interventions.

The oxygen supply must be continuous. It is necessary to ensure that sufficient ventilation of the lungs is maintained and the body is freed from carbon dioxide.