Synthesis of Hydroxylated Naphthoquinone Derivatives

A concise synthesis of naphthalene compounds for incorporation into a synthetic sequence for the rubromycin family of natural products is presented. These highly substituted naphthalenes are generated in seven and nine steps, respectively, from 2,4,5-trimethoxybenzaldehyde. Three ring-forming methods were explored and the controlled oxygenation of different positions was investigated to yield differentially substituted/protected systems. Key steps to the final products include a Stobbe condensation to form the ring system and a novel series of regioselective oxidations to introduce the required oxygen functionality. These naphthalene products incorporate orthogonal protecting groups and are suitable for combination with a variety of coupling partners.

show abstract

“…Initially, direct generation of p -quinone ( 19 ) was attempted as there was precedent for this type of transformation …”

Section: Resultsmentioning

confidence: 99%

A Concise Synthesis of the Naphthalene Portion of Purpuromycin

2008

View full text Add to dashboard Cite

show abstract

“…A corresponding two‐step procedure allowed a direct allylation of carboxylic acids . We applied a more efficient process, using the modified Me 2 AlCl/MeONHMe·HCl reagent system for the preparation of Weinreb's amide 4 (74%) from homochinchomeric acid dimethyl ester 3 , readily obtained (89%) by microwave (MW) promoted mono‐decarboxylation of pyridyl malonate 2 (Scheme ) .…”

Section: Resultsmentioning

confidence: 99%

Studies on Reactive Pyridylketones Formed by Weinreb Transformations

Stockmann

Kaspersen

Nicolaisen

et al. 2012

Journal of Heterocyclic Chem

View full text Add to dashboard Cite

A method has been developed to allow the preparation of reactive pure vinylpyridylketones and activated vinylketones, in general, to be used in further reactions, such as cycloadditions. The process is based on the Weinreb's amide transformation and includes a quarternary ammonium intermediate and subsequent elimination. Additionally, based on our previous results on the malonate alkylation of 3-nitropyridines and subsequent synthetic applications, we present the studies on the transformation of pyridyl malonate derivative 3 via the Weinreb's amide 4 and reactive methylpyridyl-(17) and allylpyridyl-ketone (6) into bis-heterocyclic products 18 and 19, and 8, 20, and 21, respectively. J. Heterocyclic Chem., 49, 613 (2012). RESULTS AND DISCUSSIONWeinreb's amides, N-methoxy-N-methyl amides, formed by ester aminolysis [15], are useful intermediates © 2012 HeteroCorporation Scheme 2 Scheme 3 Scheme 1 Scheme 4

show abstract

“…Juglone [47] Juglone (5-hydroxy-1,4-naphthoquinone) (15), is a naturally occurring compound, isolated from leaves of Juglans regia (walnut leaves) [48,49]. It has been also prepared synthetically employing several approaches [50][51][52][53].…”

Section: Allicinmentioning

confidence: 99%

Natural Product-Based Phenolic and Nonphenolic Antimicrobial Food Preservatives and 1,2,3,4-Tetrahydroxybenzene as a Highly Effective Representative: A Review of Patent Literature 2000-2005

Galal

2006

PRI

View full text Add to dashboard Cite

Conventional chemical preservatives used in prevention of food spoilage caused by microorganisms have shown adverse effects and found to be of low effectiveness. This challenging situation stimulated research to find alternatives. As a result, numerous natural product-based compounds have been patented for use as antimicrobial food preservatives. These compounds comprise phenolic and non-phenolic ones. The phenolic agents include mainly those composed of a single aromatic ring and flavonoid-derived molecules. The phenolic compounds display multifunctional activities, while the nonphenolic do not. Polyhydroxybenzene derivatives exhibit high potential as effective antimicrobial or as antioxidants agents. Among the later category is 1,2,3,4-tetrahydroxybenzene (THB). THB has been recently patented as a highly effective antimicrobial and antioxidant agent. It showed significant and broad-spectrum antimicrobial activity versus a wide range of gram-positive, gram-negative bacteria, yeasts, and fungi, including pathogenic and non-pathogenic organisms. Its effectiveness as an antioxidant is equal or superior to commonly used antioxidants such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). Production of 1,2,3,4-tetrahydroxybenzene was accomplished efficiently by adopting a bioengineered synthesis, that is recently disclosed. In addition, there is also a patented simple chemical method.

show abstract

Synthesis of Hydroxylated Naphthoquinone Derivatives

Cited by 15 publications

References 44 publications

A Concise Synthesis of the Naphthalene Portion of Purpuromycin

A Concise Synthesis of the Naphthalene Portion of Purpuromycin

Studies on Reactive Pyridylketones Formed by Weinreb Transformations

Natural Product-Based Phenolic and Nonphenolic Antimicrobial Food Preservatives and 1,2,3,4-Tetrahydroxybenzene as a Highly Effective Representative: A Review of Patent Literature 2000-2005

Contact Info

Product

Resources

About