Synthesis of azaanthraquinones: homolytic substitution of pyridines

1982 ◽  
Vol 35 (7) ◽  
pp. 1451 ◽  
Author(s):  
DW Cameron ◽  
KR Deutscher ◽  
GI Feutrill ◽  
DE Hunt
Keyword(s):  
Ring Closure ◽  
Pyridine Derivatives ◽  
Derivatives Of ◽  
Substituted 1 ◽  
Homolytic Substitution

Synthesis of specific di- and tri-hydroxyazaanthraquinones by Friedel-Crafts procedures is limited by orientational ambiguity and by the lack of reactivity of pyridine derivatives in electrophilic acylation processes; however, suitable pyridines have been made to undergo radical benzoylation and benzylation at unsubstituted positions 2, 4 and 6. In particular, derivatives of pyridine-3-carbo-nitrile have been benzoylated at positions 2 and 4. Ring closure by intramolecular Houben-Hoesch reaction has then led to specifically substituted 1-and 2-azaanthraquinones and thence to the antibiotic bostrycoidin (1).

One-pot, Three-component Synthesis of 7H-[1,3,4]Thiadiazolo[ 3,2-a]pyridines from 2-Phenacyl-[1,3,4]thiadiazole Derivatives and Arylmethylene-cyanoacetic Acid Derivatives

2007 ◽  
Vol 62 (10) ◽  
pp. 1298-1304 ◽  
Author(s):  
Imran Ali Hashmi ◽  
Wolfgang Frey ◽  
Ivo C. Ivanovc ◽  
Willi Kantlehner
Keyword(s):  
Ring Closure ◽  
The Novel ◽  
Pyridine Derivatives ◽  
Cyanoacetic Acid ◽  
One Pot ◽  
X Ray ◽  
Thiadiazole Ring ◽  
Thiadiazole Derivatives ◽  
Hydroxy Compounds ◽  
Derivatives Of

Generally, arylmethylene-cyanoacetic acid derivatives react with enols and aromatic or heteroaromatic hydroxy compounds to afford 2-amino-4H-pyran derivatives of type 6. In contrast, a ring closure with the nitrogen atom of the thiadiazole ring occurs when 2-phenacyl-1,3,4-thiadiazoles (1a - d) act on derivatives of arylmethylene-cyanoacetic acid giving rise to the formation of 7H- [1,3,4]thiazolo[3,2-a]pyridine derivatives 5a - r. The same products are obtained if 2-phenacyl-1,3,4- thiadiazoles react with aromatic or heteroaromatic aldehydes and cyanoacetic acid derivatives. The constitution of the novel compounds 5 has been confirmed by an X-ray analysis of 5a.

Synthesis, characterization and biological activities of 1,3,4-oxadiazole derivatives of nalidixic acid and their copper complexes

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Nalidixic Acid ◽  
Copper Complexes ◽  
Biological Activities ◽  
Bidentate Coordination ◽  
Antibacterial And Antifungal Activities ◽  
Elemental Analyses ◽  
Oxadiazole Derivatives ◽  
Antibacterial And Antifungal ◽  
Derivatives Of ◽  
Substituted 1

A series of novel 1, 3, 4-oxadiazole analogues was synthesized from cyclization of hydrazones of substituted 1-ethyl-1,4-dihydro-7-methyl-4-oxo-1,8-naphthyridine-3-carbohydrazides were prepared from nalidixic acid. The structures of synthesized oxadiazole derivatives and their copper complexes were elucidated on the basis of FTIR, elemental analyses, 1H-NMR and atomic absorption spectral analysis. It was observed from spectral data that metal ligand ratio was 1:1 in all copper complexes and they were bidentate, coordination was found to be done through oxygen of 4-oxo group and nitrogen of oxadiazole ring. The synthesized compounds were further evaluated with biological activities and compared with parent hydrazones. Copper complexes possess antibacterial and antifungal activities better than the oxadiazoles while they have better antioxidant activity then copper complexes. Parent hydrazones were better in all biological activities than synthesized oxadiazoles.

New 4-Hydroxypyridine and 4-Hydroxyquinoline Derivatives as Inhibitors of NADH-ubiquinone Reductase in the Respiratory Chain

1989 ◽  
Vol 44 (7-8) ◽  
pp. 609-616 ◽  
Author(s):  
Kun Hoe Chung ◽  
Kwang Yun Cho ◽  
Yasuko Asami ◽  
Nobutaka Takahashi ◽  
Shigeo Yoshida
Keyword(s):  
Electron Transport ◽  
Respiratory Chain ◽  
Side Chain ◽  
Pyridine Derivatives ◽  
Transport Function ◽  
Optimal Length ◽  
Structure Activity ◽  
Membrane Effect ◽  
Relationship Of ◽  
Derivatives Of

Many derivatives of 2,3-dim ethoxy-4-hydroxypyridine, which were designed from examination of the structure-activity relationship of piericidins, were tested for inhibition of NADH-UQ reductase. The lipophilic side chain of those compounds was indicated to be a key part for activity and its optimal length was conjectured. By the use of two different phases of assay material, intact mitochondria and submitochondria, the size of a membrane effect was shown to depend on the structure of the side chain. 4-Hydroxyquinoline derivatives were also tested for an analogous role in relation to the electron transport function of menaquinone, and they were proven to be inhibitors of NADH-UQ reductase as good as the pyridine derivatives.

scholarly journals Synthesis, Oral Bioavailability and in vivo Activity of Acetal Derivatives of the Selective Antiherpesvirus Agent 9-(3-hydroxypropoxy) Guanine (BRL 44385)

1994 ◽  
Vol 5 (3) ◽  
pp. 147-154
Author(s):  
M. R. Harnden ◽  
R. J. Ashton ◽  
M. R. Boyd ◽  
L. J. Jennings ◽  
D. Sutton ◽  
...  
Keyword(s):  
Oral Administration ◽  
Oral Bioavailability ◽  
Oral Delivery ◽  
Ring Closure ◽  
Guanine Derivatives ◽  
Derivatives Of ◽  
Lesion Severity ◽  
Hsv 1

Acyclic acetal derivatives of the selective antiherpesvirus agent 9-(3-hydroxypropoxy) guanine (BRL44385) and of its 2-aminopurine congener (BRL46720) have been prepared and evaluated in mice for oral delivery of BRL 44385. Guanine derivatives (6 a-c) were prepared via Mitsunobu condensation of an alcohol with a 9-hydroxy-6-methoxypurine (Harnden and Wyatt, 1990). Synthesis of derivatives of 2-aminopurine (10 a-d) was achieved by hydrogenolysis of 9-alkoxy-6-chloropurines, which were obtained either by reaction of an alkoxyamine with 4,6-dichloro-2,5-diformamidopyrimidine and subsequent ring closure or by Mitsunobu condensation of an alcohol with a 6-chloro-9-hydroxypurine. Following oral administration, 2-amino-9-[3-(iso-propoxymethyl)propoxy]-purine (10b, BRL 55792) was very well absorbed and provided high and prolonged concentrations of BRL44385 in the blood. In a cutaneous HSV-1 infection in the ear pinna of mice, orally dosed BRL 55792 was at least 3-fold more potent than both BRL44385 and Acyclovir in reduction of lesion severity.

Synthesis of 1-Hydroxypyrrolidin-2,5-dione Derivatives of the Phosphonic - Hydroxamic Acid Antibiotic SF-2312

2006 ◽  
Vol 59 (4) ◽  
pp. 283 ◽  
Author(s):  
Wamuyu Owotoki ◽  
Detlef Geffken ◽  
Thomas Kurz
Keyword(s):  
Hydroxamic Acid ◽  
Phosphonic Acids ◽  
Trialkyl Phosphites ◽  
Derivatives Of ◽  
Substituted 1 ◽  
Ring Position

Analogues of the antibiotic SF-2312 with a 3-substituted 1-hydroxypyrrolidine moiety have been prepared from 1-benzyloxy-3-bromopyrrolidin-2,5-dione (1) through Michaelis–Arbusov reaction with various trialkyl phosphites and subsequent alkylation of ring position 3. Cleavage of phosphonic esters 3 by TMSBr afforded the corresponding phosphonic acids 7, which were treated with ethanolamine to give the monosalts 8. Finally, hydrogenolysis furnished 1-hydroxypyrrolidin-2,5-diones 9.

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