Über
            <i>p</i>
            ‐Oxy‐ und
            <i>p</i>
            ‐Amino‐phenyl‐lutidine

Emmert, Bruno; Diefenbach, Ernst; Eck, Reinhard

doi:10.1002/cber.19270600931

Cited by 12 publications

(3 citation statements)

References 5 publications

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“…Antiviral Evaluation Method. The anti-EMC virus activity of compounds in this study was determined in CF-1 male mice, [15][16][17] g each, at the several dose levels indicated in Table I. Ten mice were used for each dose level of a compound, and the control group for each compound was 20-30 untreated mice.…”

Section: Methodsmentioning

confidence: 99%

Bis-basic-substituted polycyclic aromatic compounds. New class of antiviral agents. 5. Bis-basic ethers of anthraquinone and bisalkamine esters of anthraquinonedicarboxylic acids

Ad¹,

Er²,

Fw³

et al. 1974

J. Med. Chem.

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Section: Methodsmentioning

confidence: 99%

Bis-basic-substituted polycyclic aromatic compounds. New class of antiviral agents. 5. Bis-basic ethers of anthraquinone and bisalkamine esters of anthraquinonedicarboxylic acids

Ad¹,

Er²,

Fw³

et al. 1974

J. Med. Chem.

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“…During discovery of Nifedipine, Loev and co-worker [1] reported that the N-phenyl-1,4-dihydropyridine is also formed by reaction of benzalaniline and acetoacetic ester [2,3]. In addition to the dihydropyridine obtained in small yields, another substance also obtained as the major product, which had previously been assigned the incorrect sructure [4].…”

Section: Introductionmentioning

confidence: 93%

Synthesis and structural conformation of N‐substituted 1,4‐dihyropyridine derivatives

Mahendra

Doreswamy

Sridhar

et al. 2005

Cryst. Res. Technol.

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“…The oxidation of 4-(4-hydroxyphenyl) Hantzsch ester 17 23 with 1 was carried out on 5 mmol scale for a period of 2 h as described above.…”

Section: Diethyl 4-(4-hydroxy-5-nitrophenyl)-26-dimethylpyridine-35mentioning

confidence: 99%

Bismuth Nitrate Pentahydrate: A Convenient Reagent for the Oxidation of Hantzsch 1,4-Dihydropyridines

Mashraqui

Karnik

1998

Synthesis

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Bi(NO 3 ) 3 ·5 H 2 O (1), an inexpensive crystalline solid readily oxidises several 4-substituted Hantzsch 1,4-dihydropyridines in acetic acid medium at room temperature. The reaction conditions are mild, easy to execute and the isolated yields of the oxidised products are fair to excellent. However, oxidation of 4-isopropyl-1,4 DHP 16 with 1 afforded the dealkylated pyridine 9, whereas the oxidation of 4-(4-hydroxyphenyl) Hantzsch ester 17 was accompanied by the nitration at the phenolic ring to form 18 in good yield.Hantzsch 1,4-dihydropyridines (Hantzsch 1,4-DHP) have been extensively utilised as the analogs of NAD(P)H coenzymes to study the mechanism and synthetic potential of various redox processes. 1,2 In addition, several 1,4-DHP based drugs, such as Nifedipine and Niguldipine have been recognised as calcium entry blockers for the treatment of cardiovascular diseases. 3-5 Both during the redox processes 2 and in the course of drug metabolism, 3 1,4-DHP systems are oxidatively transformed into the corresponding pyridine derivatives. Furthermore, the oxidation of readily accessible Hantzsch 1,4-DHP constitutes by far the easiest method to obtain pyridine derivatives. As a consequence, newer and improved methods to effect the oxidation of 1,4-DHP systems continued to be investigated. 6-14 However, many of the reported oxidation procedures either suffer from the use of strong oxidants (HNO 3 , 5 CrO 3 , 6 KMnO 4 7 ), require severe conditions (S 8 , and Pd/C dehydrogenations 9 ) or need excess of the oxidants (CAN, 10 PCC 11 ). In connection with our interest in the chemistry of dihydropyridines and related systems, 15,16 we became interested in developing a milder and convenient method to effect 1,4-DHP to pyridine conversion. We now report that Bi(NO 3 ) 3 · 5 H 2 O (1), a commercially available, inexpensive, crystalline solid, serves as an excellent oxidant for a variety of 4-substituted Hantzsch 1,4-DHP systems as shown in the generalised Scheme 1. Our results are collected in the Table. Our initial attempts to effect the oxidation of the simple Hantzsch 1,4-DHP 2 20 (R = H, Table) as a test case with 1 in CH 3 OH, CH 3 CN, or CH 3 COCH 3 solvents at ambient or thermal conditions produced none or insignificant amount of the corresponding pyridine (9, entry 1). However, to our delight, the oxidation of 2 with a stoichiometric amount of 1 in acetic acid occurred smoothly at room temperature to afford the expected pyridine 9 in 75% isolated yield (quantitative conversion by TLC). The success of this reaction prompted us to study the oxidation of several 4-alkyl, aryl and alkenyl Hantzsch 1,4-DHP under the above conditions. All reactions were stirred at room temperature until the substrates were completely consumed. The crude products obtained upon extractive workup are purified by short silica gel column chromatography or crystallisation, and the isolated yields of the oxidised products are fair to excellent (50-90%). The unique role of acetic acid in promoting these oxidations may be tentatively attributed ...

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Über p ‐Oxy‐ und p ‐Amino‐phenyl‐lutidine

Cited by 12 publications

References 5 publications

Bis-basic-substituted polycyclic aromatic compounds. New class of antiviral agents. 5. Bis-basic ethers of anthraquinone and bisalkamine esters of anthraquinonedicarboxylic acids

Bis-basic-substituted polycyclic aromatic compounds. New class of antiviral agents. 5. Bis-basic ethers of anthraquinone and bisalkamine esters of anthraquinonedicarboxylic acids

Synthesis and structural conformation of N‐substituted 1,4‐dihyropyridine derivatives

Bismuth Nitrate Pentahydrate: A Convenient Reagent for the Oxidation of Hantzsch 1,4-Dihydropyridines

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