An expedient protocol of the Biginelli dihydropyrimidine synthesis using carbonyl equivalents
作者:Kamaljit Singh、Jasbir Singh、Prasant K. Deb、Harjit Singh
DOI:10.1016/s0040-4020(99)00760-7
日期:1999.10
A one - pot condensation of perhydro-1,3 heterocycles - aldehyde equivalents with ethyl acetoacetate and ureas provides a convenientsynthesis of the title compounds with a variety of substituents at C-4. Yields are equivalent or significantly higher than the conventional methods.
Novel process for producing 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate-3-methyl ester-5-beta-(N-benzyl-N-methylamino)ethyl ester
申请人:HIGASHIKAWA, Tetsuro
公开号:EP0445987A2
公开(公告)日:1991-09-11
Nicardipine hydrochloride, i.e. 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate 3-methyl ester-5-β-(N-benzyl-N-methylamino)ethyl ester, is prepared in a short time at a high yield by reacting, in a non-aqueous system, m-nitrobenzaldehyde or another compound of formula (1)
wherein either R₁ and R₂ are taken together and represent =O or =N-lower alkyl, or R₁ represents -O-, R₂ represents -NH-, and R₁ and R₂ are linked via C₂₋₄ straight or branched-chain alkylene to form a saturated heterocyclic ring which may be substituted, simultaneously or sequentially, in either order, with methyl 3-aminocrotonate and (N-methyl-N-benzylamino)ethyl 3-aminocrotonate.
Modified Pictet–Spengler reaction. A highly diastereoselective approach to 1,2,3-trisubstituted-1,2,3,4-tetrahydro-β-carbolines using perhydro-1,3-heterocycles
作者:Kamaljit Singh、Prasant K Deb、P Venugopalan
DOI:10.1016/s0040-4020(01)00763-3
日期:2001.9
A flexible variant of the Pictet-Spengler reaction employing oxazinanes as synthetic equivalents of several carbonyl compounds has been developed. Using acid catalyzed one pot condensation of perhydro-1,3-heterocycles various 1,3-disubstituted and 1,2,3-trisubstituted-1,2,3,4-tetrahydro-beta -carbolines (THBCs) have been synthesized diastereoselectively. (C) 2001 Elsevier Science Ltd. All rights reserved.
Efficient and versatile single pot approach to dipyrromethanes and bis(heterocyclyl)methanes
An efficient single pot route is presented involving the use of 0, N-perhydro 1,3-heterocycles as carbonyl equivalents for the synthesis of 5-substituted dipyrromethanes, 5,10-disubstituted tripyrranes and bis(heterocyclyl)methanes. (c) 2005 Elsevier Ltd. All rights reserved.
SINGH, HARJIT;SINGH, KAMALJIT, TETRAHEDRON, 45,(1989) N2, C. 3967-3974