- An improved one-pot synthesis of N-(2,3-dihydrobenzo[1,4]dioxin-2-carbonyl) piperazine - Useful intermediate for anti-hypertensive drug - Doxazosin
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An improved process for the preparation of N-(2,3-dihydrobenzo[1,4]dioxin- 2-carbonyl)piperazine 2 and its hydrochloride from ethyl-2,3-dihydro-1,4- benzodioxin-2-carboxylate 3 and piperazine in a single step has been described. The compound 2 is an important intermediate in the preparation of anti-hypertensive agent, Doxazosin.
- Ramesh, Chakka,Reddy, Reguri Buchi,Reddy, Ghanta Mahesh
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- Efficient monoacylation of symmetrical secondary alkanediamines and synthesis of unsymmetrical diacylated alkanediamines. A new L-proline-based organocatalyst
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A simple procedure was developed for the monoacylation of several unprotected alkanediamines with carboxylic acids by using PyBOP-HOBt as coupling agent in the presence of DIEA at room temperature. Yields were moderate with primary alkanediamines and good to excellent with linear or cyclic secondary ones. To illustrate the utility of these monoacylated products, six unsymmetrical diacylated alkanediamines were synthesized. In addition, one of these compounds was evaluated as organocatalyst in an asymmetric aldol reaction. R' R' NHR O R N O R N PyBOP, HOBt PyBOP, HOBt DIEA, DMF DIEA, DMF NHR NHR O N O 10 equiv O R 11 exemples R' R = H, alkyl R'' OH 67-95% yield R'' OH 6 exemples
- Moulat, Laure,Martinez, Jean,Salom-Roig, Xavier J.
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p. 336 - 349
(2020/02/13)
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- Method for synthesizing doxazosin
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The invention discloses a method for synthesizing doxazosin and belongs to the technical field of chemical synthesis. According to the method, the doxazosin is synthesized by adopting a synthesis route, represented by formulae shown in the description, different from the conventional technologies, and thus a novel synthesis route is provided for preparing the doxazosin; and the method has the advantages of moderate conditions, simple and convenient steps and high yield, and the doxazosin can be obtained simply and efficiently.
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- PREPARATION AND UTILITY OF SUBSTITUTED QUINAZOLINE COMPOUNDS WITH ALPHA-ADRENERGIC BLOCKING EFFECTS
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The present disclosure is directed to modulators of alpha-adrenergic receptors and pharmaceutically acceptable salts and prodrugs thereof, the chemical synthesis thereof, and the use of such compounds for the treatment and/or management of hypertension, cardiac failure, prostatitis, and benign prostatic hyperplasia, and any other condition in which it is beneficial to modulate an alpha-adrenergic receptor.
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Page/Page column 71
(2008/06/13)
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- Direct synthesis of N-acylalkylenediamines from carboxylic acids under mild conditions
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Monoacylated piperazine derivatives were prepared directly from carboxylic acids and piperazine using triphenylphosphine (TPP) and N-bromosuccinimide (NBS) in dichloromethane. Inexpensive and readily available reagents, excellent yields, short reaction times and mild reaction conditions are important features of this method.
- Bandgar,Bettigeri
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p. 2917 - 2924
(2007/10/03)
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- Process for the preparation of N-(2,3-dihydrobenzo 1,4 dioxin-2-carbonyl) piperazine
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The present invention provides a process for the preparation of N-(2,3-Dihydrobenzo[1,4]dioxin-2- carbonyl)piperazine which comprises heating a reaction mixture of 2,3-dihydrobenzo[1,4]dioxin-2-carboxylate and piperazine with a molar ratio of carboxylate to piperazine in the range of 1:2 to 2:1, under nitrogen atmosphere, at a temperature in the range of 70-90 °C for a period of 3-15 hrs, cooling the above said reaction mixture to a temperature of 25-30 °C and dissolving it in chloroform followed by washing with saturated sodium bi-carbonate solution and water respectively, acidifying the organic layer by about 10% HCl to a pH ranging between 1 to 4, separating the organic layer and washing the aqueous layer with chloroform, basifying the aqueous layer with sodium bi-carbonate to a pH ranging between 7 to 9 followed by extracting with chloroform and evaporating the chloroform to obtain the final desired product in amorphous solid form.
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- Highly rapid and direct synthesis of monoacylated piperazine derivatives from carboxylic acids under mild conditions
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A series of monoacylated piperazine derivatives were obtained by the reaction of carboxylic acids with 2-chloro-4,6-dimethoxy-1,3,5-triazine in dichloromethane at room temperature. Good to excellent yields, short reaction times and mild reaction conditions are important features of this methodology.
- Bandgar,Pandit
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p. 3855 - 3858
(2007/10/03)
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- Process for preparing amides
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The present invention provides a process for preparing an amide, which comprises reacting an amine with an ester in a molten form in the absence of a solvent.
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- HMDS-promoted in situ amidation reactions of carboxylic acids and amines
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A number of N-acylalkylenediamines were synthesized in high yields by in situ monoamidation of carboxylic acids with diamines. The amidation reactions were carried out simply by heating the substrates at 110 °C for 5-24 h in the presence of HMDS.
- Chou, Wen-Chih,Chou, Ming-Chen,Lu, Yann-Yu,Chen, Shyh-Fong
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p. 3419 - 3422
(2007/10/03)
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