Synthesis of paracetic pain (Benorylate).

. Objective: Objective: 1. Through the preparation of acetyl salimyl chlorine, to understand the selection of
reagents
chlorinated and operational precautions.
2. Through this experiment, we understand the application of the flattening principle in chemical structure modification.
3. Through this experiment, we understand the principle of Schotten-Baumann esterification reaction. 2, experimental principle paracetamotic pain as a new anti-heat analgesic anti-inflammatory drug, is made by aspirin and paracetamotic pain by flattening principle, it not only retains the anti-heat analgesic function of the original medicine, but also reduces the toxic side effects of the original drug, and has synergies.
for acute, chronic rheumatoid arthritis, rheumatoid pain, cold fever, headache and nerve pain. Paracetamol chemistry is called 2-acetyloxybenzene-acetylamide, chemical structure is:
paracetamol pain for white crystalline powder, odorless and odorless. mp.174 to 178 degrees C, insoluble in water, slightly soluble in ethanol, soluble in chloroform, acetone.iii, experimental method(i) preparation of acetyl salimyl chloride
in the
drying
100 mL round bottom
samk
, in turn added 2 drops of radon , aspirin 10 g, chlorpyridine 5.5 mL, quickly press on the spherical condenser (with calcium chloride drying tube attached to the top, dry pipe connected to the air-conductive tube, the other end of the catheter through the water tank mouth).
the oil bath slowly
heat
to 70 degrees C (about 10 to 15 min), maintain the oil bath temperature at 70±2 degrees C reaction 70 min, cool, add waterless acetone 10 mL, pour the reaction fluid into the dry 100 mL drop
funnel
, mix well, close spare.
(ii) preparation for paraceliitis pain
in a 250 mL three-neck bottle with a mixing rod and
thermometer
, add paracelione pain 10 g and water 50 mL. Ice water bath cold to about 10 degrees C, in the stirring drop of sodium hydroxide solution (sodium hydroxide 3.6 g plus 20 mL water distribution, with dropper drops added).
drops are added, between 8 and 12 degrees C, in a strong stirring, slowly add the second experimentally made acetyl sulphate ketamine solution (at about 20 min drop finished). Drops are added, adjusted to pH≥10, control temperature between 8 to 12 degrees C to continue stirring reaction 60 min, filtration, washing to neutral, rough, calculated yield.
(iii) refined
take 5 g of crude 5 g placed in a 100 mL round bottom bottle equipped with a spherical condenser, add 10 times the amount (w/v) 95% ethanol, heat and dissolve on the water bath. Slightly cold, add activated carbon decoloration (the amount of activated carbon depends on the color of the rough), heating back 30 min, while hot pumping filter (Breitling funnel, filter bottle should be preheated).
Transfer the filter liquid while hot to the
Berries
, natural cooling, to be crystallized after complete analysis, filtration, pressure drying;
(4) structure confirms the
. 1. Infrared absorption
spectral
, standard TLC control method.
2. Mr. Spectroscopy.note:
1. Dichloroacetylamide is the most commonly used chlorinated reagent for the preparation of acetate, which is not only cheap but also has a low boiling point, and produces by-products that are volatile gases, so the resulting acetyl chloride products are easy to purify.
water can be broken down into sulfur dioxide and hydrogen chloride, so the instruments used need to be dried; Aspirin for reaction needs to be dried at 60 degrees C 4 h. As a catalyst, the amount should not be too much, otherwise affect the quality of the product. The chlorine made should not last long.
2. Paracetamol preparation is esterified using the Schotten-Baumann method, i.e. acetyl salimide chlorine and sodium acetaminophen.
Because paracetamol hydroxygen and benzene ring conjugate, coupled with the benzene ring and electron-absorbing acetylamide base, so the phenol hydroxyl electronic cloud density is lower, the pro-nuclear reaction is weak; .