4,4'-DDT synthesis

8synthesis methods

Product Name:4,4'-DDT
CAS Number:50-29-3
Molecular formula:C14H9Cl5
Molecular Weight:354.49

DDT, 2,2-bis-(p-chloro-phenyl)-1,1,1-trichloroethane can be obtained by reacting one mol of chloral with two mols of chlorobenzene in the presence of sulfuric acid: All operations were carried out under a hood Fifteen and five-tenths grams (0.105 mol) of chloral was obtained by mixing the required amount of U. S. P. chloral hydrate with twice its weight d sulfuric acid, and distilling the chloral layer which readily separates. The chloral was dissolved in 22.5 Gm. (0.2 mol) of chlorobenzene (Eastman, Practical grade) and the solution was cooled to 5℃. under constant stirring. A temperature of from 5 to 10℃. was maintained, and to the solution, under constant stirring, were added dropwise twelve 1-cc. portions of chlorosulfonic acid (Eastman, Practical grade) at ten-minute intervals. The acid can be added safely with the use of a 5-cc. pipette. After about 8 cc. of the acid was added a solid began to separate, and within a few minutes the entire mixture became pasty. After the last portion of acid was added the stirring was continued for one hour at 10-15' C., and then for two hours at room temperature. At the end of this period the reaction mixture was mixed with chipped ice, and the crude DDT was filtered off with suction. The crude product was stirred into ten times its weight of boiling water to remove occluded acid. The product was again collected on a Biichner funnel, and washed with an equal weight of cold methanol or recrystallized once from a mixture of three parts of methanol and one part of diethyl ether. The washed product melted at 106-107℃. (uncorr.) and the recrystallized product melted at 107-108℃. (uncorr.). The yield of the purified compound was 65-70%.^[1]

79-37-8
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5471-77-2 Synthesis

3-Ethoxy-2,2-dimethyl-3-oxopropanoic acid

5471-77-2
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50-29-3
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Yield:-

Reaction Conditions:

with SiO₂ in dichloromethane;ethyl acetate;N,N-dimethyl-formamide;acetonitrile;Petroleum ether

Steps:

165.4 Step-4:
Step-4:
Compound 4
To a stirred solution of 3-ethoxy-2,2-dimethyl-3-oxopropanoic acid (10 g, 62.4 mmol) in dichloromethane (100 ml) at 0° C. was added oxalyl chloride (6.4 g, 75.6 mmol) followed by two drops DMF.
The reaction mixture was stirred at room temperature for 2 h and then concentrated under vacuum to obtain brown oil.
This was then added dropwise into a solution of 3 (15.5 g, 51.3 mmol) and DIPEA (36 ml, 206.7 mmol) in acetonitrile (100 ml) at 0° C. and stirred at room temperature for 16 h.
The reaction mixture was completely concentrated under vacuum to obtain a residue.
One more similar batch of reaction was carried out in parallel and both the residues were taken together in ethyl acetate.
The ethyl acetate layer was washed with 1.5 N HCl, 10% NaHCO₃ solution and brine, dried over anhydrous Na₂SO₄, filtered and concentrated.
The crude was purified using column chromatography (SiO₂, 15-20% ethyl acetate in petroleum ether) to yield compound 4 as white solid (25 g, 59.7%).

References:

Petter, Russell C.;Jewell, Charles F.;Lee, Kwangho;Medikonda, Aravind Prasad;Niu, Deqiang;Qiao, Lixin;Singh, Juswinder;Zhu, Zhendong US2011/269244, 2011, A1 Location in patent:Page/Page column

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