Synthesis and Reactions of Some Isoquinoline Derivatives

El‐Khawaga, Ahmed M.; El-Naggar, G. M.; Hassan, Kh. M.; El‐Dean, Adel M. Kamal

doi:10.1080/10426508908040610

“…IR: 1375, 1200 cm -' (S 0 2), and 3260cm "' (NH). (4)(5)(6)(7)(8)(9)(10)(11)(12)(13) An equim olar ratio of com pound 3 (0.05 mole) and hydrazine hydrate, saturated ethanolic solu tion of am m onia, arom atic amine or heterocyclic amine in (20 ml) ethanol was refluxed for 1/2 h, then allowed to cool. The solid product was col lected and recrystallized from suitable solvent to give com pounds 4 -13.…”

Section: -Chlorosulphonyl-46-dim Ethvl-1 [ H ] Pyrazolo-mentioning

confidence: 99%

“…For this reason and in continuation of our work, in the synthesis of het erocyclic com pounds containing pyridine fused with other heterocyclic systems [7][8][9][10][11][12][13]; this work is a trial for synthesis o f some pyrazolopyridine sulphonamide and some pyrazolopyridine sul phide derivatives. M ost of the synthesized com pounds were biologically screened against differ ent Gram positive and G ram negative strains of bacteria and most of them gave satisfactory re sults.…”

mentioning

confidence: 99%

Synthesis of Some Pyrazolopyridine Sulphonamide Derivatives

El‐Dean

¹

,

Atalla

²

,

Mohamed

³

et al. 1991

Zeitschrift Für Naturforschung B

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The diazonium salt o f 3-aminopyrazolopyridine when treated with SO: and CuCU produces the corresponding sulphonyl chloride. The sulphonyl chloride chloride easily reacts with hy drazine hydrate, amm onia, aromatic or heterocyclic amines to produce the corresponding sulphohydrazide, sulphonamide or N-sulphonam ide derivatives. Sulphohydrazide reacts with acetylacetone to produce pyrazoly pyrazolopyridinyl sulphone which is also obtained by reac tion o f sulphonyl chloride with dimethylpyrazole. The aminopyrazolopyridine can be converte into pyrazolopyridinthiole by its reacting with ethyl dithioxanthate. The pyrazolopyridinthiole reacts with alkyl halides or acrylonitrile to produce S-alkylated derivatives.

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“…while the C (8) =O (1) and C (7) -C (14) ≡N (2) groups in molecule B have cis orientation relative to the C (7) -C (8) bond (the O (1) -C (8) -C (7) -C (14) torsion angle is 9.1°), this torsion angle in molecule A is -104.6°. Only the cyclohexane ring in both independent molecules has identical chair conformation though the orientation of this ring relative to the bicyclic S (1) N (1) C (1) C (2) C (3) C (4) C (5) C (6) C (7) C (8) system in molecules A and B differs significantly: the C (10) C (11) C (12) cyclohexane "corner" is twisted toward the C (5) -C (15) ≡N (3) Thus, our X-ray diffraction structural analysis showed that two conformers exist in the crystal of 3a.…”

mentioning

confidence: 96%

“…

The reported methods for the synthesis of substituted pyrido[2,1-b] [1,3]thiazines are based on the reaction of 2-pyridinethiol with β-bromopropionic acid [1], reaction of tetrahydro-2-pyridinethione with benzylidenemalononitrile [2], reaction of 3,4-dihydropyridine-2(1H)-thione with epichlorhydrin [3], and acylation of 3,4-dihydro-2(1H)-pyridinethione with cinnamyl chloride [4].In the present work, we have found a simple and efficient method for preparing previously unreported substituted, partially hydrogenated pyrido[2,1-b][1,3]thiazines 1-4 consisting of the regioselective alkylation of 2-pyridinethiols 5-7 and 2-pyridinethiolate 8 by 1,3-dibromopropane in DMF in the presence of aqueous KOH.An X-ray diffraction structural analysis of 3a was carried out to establish the regioselectivity of the alkylation of 2-pyridinethiols 5-8 by 1,3-dibromopropane. We found that there are two symmetrically independent molecules A and B in the crystal of this compound.

…”

mentioning

confidence: 99%

“…The reported methods for the synthesis of substituted pyrido[2,1-b] [1,3]thiazines are based on the reaction of 2-pyridinethiol with β-bromopropionic acid [1], reaction of tetrahydro-2-pyridinethione with benzylidenemalononitrile [2], reaction of 3,4-dihydropyridine-2(1H)-thione with epichlorhydrin [3], and acylation of 3,4-dihydro-2(1H)-pyridinethione with cinnamyl chloride [4].…”

mentioning

confidence: 99%

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A simple and effective synthetic approach to pyrido[2,1-b]thiazines

Dyachenko

¹

,

Chernega

²

2007

Chem Heterocycl Comp

1

0

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The reported methods for the synthesis of substituted pyrido[2,1-b] [1,3]thiazines are based on the reaction of 2-pyridinethiol with β-bromopropionic acid [1], reaction of tetrahydro-2-pyridinethione with benzylidenemalononitrile [2], reaction of 3,4-dihydropyridine-2(1H)-thione with epichlorhydrin [3], and acylation of 3,4-dihydro-2(1H)-pyridinethione with cinnamyl chloride [4].In the present work, we have found a simple and efficient method for preparing previously unreported substituted, partially hydrogenated pyrido[2,1-b][1,3]thiazines 1-4 consisting of the regioselective alkylation of 2-pyridinethiols 5-7 and 2-pyridinethiolate 8 by 1,3-dibromopropane in DMF in the presence of aqueous KOH.An X-ray diffraction structural analysis of 3a was carried out to establish the regioselectivity of the alkylation of 2-pyridinethiols 5-8 by 1,3-dibromopropane. We found that there are two symmetrically independent molecules A and B in the crystal of this compound. The major geometrical parameters of these molecules are given in Table 1, while a general view of these molecules is given in Figs. 1 and 2. The bond lengths and bond angles in 3a(A) and 3a(B) are virtually identical. In particular, N (1) in both molecules has planar trigonal configuration: the sum of the bond angles at this atom is 359.0(6)° in 3a(A) and 359.9(6)° in 3a(B). In both molecules, the N (1) -C (4) and N (1) -C (8) bonds are markedly shortened relative to the standard value for the pure N(sp 2 )-C(sp 2 ) single bond (1.45 Å) [5] due to n(N (1) )-π(C (4) =C (5) ) and n(N (1) )-π(C (8) =O (1) ) conjugation. On the other hand, the conformations of these molecules differ considerably, as indicated both by the endocyclic torsion angles (Table 2) and the modified Kramer-Pople parameters, S, θ, and Ψ [6]. Thus, while the S (1) N (1) C (1) C (2) C (3) C (4) heterocycle in molecule A has chair conformation (S = 0.99, θ = 12.2°, ψ = 8.8°), this heterocycle in molecule B has twist-boat conformation (S = 0.82, θ = 65.0°, Ψ = 10.0°). The central N (1) C (4) C (5) C (6) C (7) C (8) ring in molecule A has close to half-boat conformation (S = 0.71, θ = 53.2°, Ψ = 24.2°), while this ring in molecule B has a conformation intermediate between half-boat and half-chair (S = 0.77, θ = 64.8°, Ψ = 15.7°). Furthermore, the arrangement of the endocyclic substituents differs significantly. Thus, __________________________________________________________________________________________

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