- 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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p. 373 - 376
(2007/10/03)
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- Process for the manufacture of intermediates suitable to make doxazosin, terazosin, prazosin, tiodazosin and related antihypertensive medicines
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A process is provided for the manufacture of: where R is: STR1 comprising reacting: STR2 wherein R1 may be selected from H, Methyl, Ethyl and suitable lower alkyl groups, Cn H2n+1 (where n is from 3 to 5) or any other suitable group and thereafter if desired converting the resultant product to a salt thereof.
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- Alkoxy-substituted-6-chloro-quinazoline-2,4-diones
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2,4-Diaminoquinazolines of the formula STR1 wherein Y1 is hydrogen or chloro, Y2 is OR, Y3 is hydrogen or OR such that when Y1 is hydrogen, Y3 is OR and when Y1 is chloro, Y3 is hydrogen or OR, and the pharmaceutically acceptable salts thereof; R represents an alkyl group having from one to three carbon atoms; taken separately, R1 and R2 are each hydrogen, alkyl having from one to five carbon atoms, cycloalkyl having from three to eight carbon atoms, alkenyl or alkynyl each having from three to five carbon atoms or hydroxy substituted alkyl having from two to five carbon atoms, when taken together with the nitrogen atom to which they are attached R1 and R2 form a substituted or unsubstituted heterocyclic group optionally containing an atom of oxygen, sulfur or a second atom of nitrogen as a ring member; their use as antihypertensive agents, pharmaceutical compositions containing them and intermediates for their production.
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- Antihypertensive 4-amino-2-[4-(1,4-benzodioxan-2-carbonyl) piperazin-1-yl or homopiperazin-1-yl]quinazolines
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Compounds having the formula STR1 and pharmaceutically acceptable salts thereof wherein R represents 6,7-di(lower alkoxy) or 6,7,8-tri(lower alkoxy); m is 1 or 2, X is --CHR1 -- or --CH2 CH2 --; each R1 and R0 may be the same or different and is hydrogen or lower alkyl; each of R2 and R3 is hydrogen, lower alkoxy, lower alkyl, halogen, lower alkanoyl, lower alkoxycarbonyl, --CONR4 R5 or --SO2 NR4 R5 wherein each of R4 and R5 is hydrogen or lower alkyl; processes for their preparation; and their use as regulators of the cardiovascular system, and particularly in the treatment of hypertension.
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