A New Synthesis of Pyridoxine.

Elming, Niels; Clauson-Kaas, Niels; Virtanen, Artturi I.

doi:10.3891/acta.chem.scand.09-0023

Cited by 25 publications

(9 citation statements)

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“…These results are of interest in view of the fact that mitomycins 10 bear a Me group at Structural Analyses. ~ The unsubstituted products 6a-9a are known compounds; their physical properties agree with those reported in the literature: [19-211 for 6a, [22] for 7a, [9], and [23] for 8a, [8] for 9a. Interestingly, the NMR data of 9a proved to be strictly identical with those reported in [23].…”

Section: ' )supporting

confidence: 75%

Cascade Reactions. A Simple One‐pot Synthesis of the Mitomycin Skeleton

Defoin

Geffroy

Nouën

et al. 1989

Helvetica Chimica Acta

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~ ~Nitroso-arene dienophiles 1 react regiospecifically with the conjugated dienals 2 and 3a/3b, and lead thereby to the unstable Dzels-Alder cycloadducts 4 and 5 These undergo two types of cascade reactions which give pyridmium betaines 6 and pyrrolo-indoles 8 as the major reaction products The one-pot syntheses of pyrroloindoles 8 represent a new and easy access to the basic skeleton of mitomycins 10 The scope and limitations of the cascade reactions were investigated Diels-Alder Cycloadditions of Nitroso-arene Dienophiles with Conjugated Dienals and their Cascade Reactions'). -We shall describe herein some cascade-reaction sequences which we observed, when conjugated dienals were treated with nitrosoarene dienophiles 1. To our knowledge, no cycloaddition reactions have been described so far between nitroso dienophiles and linear conjugated dienals. Nevertheless, some oximeand dimethylacetal derivatives of these dienals are known to undergo Diels-Alder reactions with nitroso dienophiles [2-71.The reaction of nitrosobenzene with pentadienal2 or with the commercially available mixture of hexadienals 3a (80 YO) and 3b (20 YO) occurred rapidly leading, in each instance, to four heterocyclic products, none of which being the expected primary Diels-Alder adduct. For example, the reaction of pentadienal 2 with PhNO gave the betaine 6a, trace amounts of the pyrrole-2-carbaldehyde 7a, the tricyclic alcohol 8a, and the corresponding ketone 9a (Scheme I). It should be noted that the preparation of the tricyclic products 8a and 9a, via a different multistep approach, had already been described as part of a synthetic plan for the mitomycins [8-lo].Mitomycins 10 represent a class of well-known natural products [l 11 which exhibit antibiotic and antitumor properties [12].Since our procedure for the synthesis of pyrrolo-indoles 8a/8b and 9a/9b represents a new one-pot process, using easily available starting materials, we decided to investigate the scope and limitations as well as the mechanism of these obviously complex cascade reactions (see below), our ultimate goal being the synthesis of some mitomycin derivatives.

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Section: ' )supporting

confidence: 75%

Cascade Reactions. A Simple One‐pot Synthesis of the Mitomycin Skeleton

Defoin

Geffroy

Nouën

et al. 1989

Helvetica Chimica Acta

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“…Chloro-2-methylaniline (80.3 g) and 2,5-dimethoxytetrahydrofuran (75 g) were heated to reflux in glacial acetic acid (120 mL) (Elming and Clauson-Kaas, 1952). After 3 h the mixture was diluted with water and extracted with diethyl ether to give, after washing with saturated aqueous potassium carbonate and removal of the solvent in vacuo, 1-(3-chloro-2-methylphenyl)pyrrole (98.8 g, 91 %): NMR 6 2.20 (s, 3 H, CH3), 6.27-6.33 (m, 2 H, -N=CH-), 6.67-6.75 (m, 2 H, -N=CH-CH=), 7.07-7.43 (m, 3 H, aromatic H's).…”

Section: -Methyl-3-(1h-pyrrol-l-yl)benzenemethanol 3-mentioning

confidence: 99%

“…The benzyl bromide was converted to (2-bromo-3-nitropheny1)methyl acetate with potassium acetate in acetonitrile in the presence of tetrabutylammonium chloride (Normant et al, 1975). Catalytic reduction of this nitro compound in the presence of platinum oxide and morpholine (Kosak, 1980) gave (3amino-2-bromopheny1)methyl acetate, which was converted to [2-bromo-3-(1H-pyrroI-l-yl)phenyl]methyl acetate (64%) by the method of Elming and Clauson-Kaas (1952). Hydrolysis with potassium hydroxide in methanol gave 2-bromo-3-(1H-pyrrol-l-yl)benzenemethanol (90% ):…”

Section: -Bromo-3-(lh-pyrrol-l-yl)benzenemethanolmentioning

confidence: 99%

“…This was reduced (platinum oxide catalyst and morpholine) and the resultant amine converted to 2,6-difluoro-3-(1H-pyrrol-l-yl)benzoic acid (43%) by the method of Elming and Clauson-Kaas (1952). This was then reduced to 2,6-difluoro-3-( 1H-pyrrol-l-y1)benzenemethanol as described in method A NMR 6 at 2.65 (br s, l H, OH), 4.85 (br s, 2 H, CH2), 6.33-6.43 (m, 2 H, -N=CH-), 6.97-7.03 (m, 2 H, -N=CH-CH=), 6.77-7.53 (m, 2 H, phenyl H's).…”

Section: 6-difluoro-3-(1h-pyrro1-l-yl)benzenemethanol 26-mentioning

confidence: 99%

“…(3-Amino-2,6-dimethylphenyl)methyl acetate was converted to [2,6-dimethyl-3-( 1H-pyrrol-l-y1)phenyllmethyl acetate (63%) by the method of Elming and Clauson-Kaas (1952). (3-Amino-2,6-dimethylphenyl)methyl acetate was converted to [2,6-dimethyl-3-( 1H-pyrrol-l-y1)phenyllmethyl acetate (63%) by the method of Elming and Clauson-Kaas (1952).…”

Section: -(2346-tetrafluorophenyl)pyrrole (92%) Was Prepared By Tmentioning

confidence: 99%

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Heterocyclic analogs of substituted [1,1'-biphenyl]-3-methylpyrethroid insecticides

Plummer¹,

Stewart²

1984

J. Agric. Food Chem.

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Application of the AAA Reaction to the Synthesis of the Furanoside ofC-2-epi-Hygromycin A: A Total Synthesis ofC-2-epi-Hygromycin A

2002

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A strategy for stereocontrolled syntheses of furanoside type of natural products is developed for a glycosyl aryl ether. This strategy resolves the issue of low diastereoselectivity typical of normal glycosidation methods for furanosides. All the stereochemistry ultimately derives from a desymmetrization of a 2,5-diacyloxy-2,5-dihydrofuran using Pd catalyzed asymmetric allylic alkylation which sets both the absolute stereochemistry and 1,4-relative stereochemistry. Diastereo-controlled elaboration of the 3,4-double bond then completes the synthesis. A new conjunctive reagent, 1-nitro-1-phenylsulfonyl-ethane, is developed to serve as an acyl anion equivalent. The utility of a phenol as a nucleophile in the Pd catalyzed glycosylation is demonstrated. From this strategy emerged a short, practical synthesis of C-2-epi-hygromycin A.

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A New Synthesis of Pyridoxine.

Cited by 25 publications

References 0 publications

Cascade Reactions. A Simple One‐pot Synthesis of the Mitomycin Skeleton

Cascade Reactions. A Simple One‐pot Synthesis of the Mitomycin Skeleton

Heterocyclic analogs of substituted [1,1'-biphenyl]-3-methylpyrethroid insecticides

Application of the AAA Reaction to the Synthesis of the Furanoside ofC-2-epi-Hygromycin A: A Total Synthesis ofC-2-epi-Hygromycin A

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