Organic Oxidations by Iodic Acid

Evans, Theodore W.; Dehn, William M.

doi:10.1021/ja01372a031

Cited by 37 publications

(15 citation statements)

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“…2 Thermal decomposition of N-arylthioureas gives aryl isothiocyanates. 3 Oxidation of arylthioureas with lead tetraacetate 4 or iodic acid 5 affords arylcyanamides. Thioureas condense with a-halocarbonyl compounds to afford 2-amino-1,3-thiazoles.…”

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confidence: 99%

Synthesis of Mono- and N,N-Disubstituted Thioureas and N-Acylthioureas

Katritzky¹,

Kirichenko²,

Rogovoy³

et al. 2004

Synthesis

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1-Benzotriazole-1-carbothioamide (2), prepared from 1-cyanobenzotriazole (1) and hydrogen sulfide, reacts with amines to give thioureas 3a-e. Reactions of (benzotriazol-1-yl)carboximidamides 4a-d,f-j and acyl-5a-f,i-k or arylaminocarbonyl-5g,h (benzotriazol-1-yl)carboximidamides with hydrogen sulfide give the corresponding thioureas 3a-d,f-j, and N-acylthioureas 6a-f,i-k or N-carbamoylthioureas 6g,h, respectively.Thiourea moieties are important chemical building blocks that have numerous chemical and pharmaceutical applications. For example, recent reports describe thiourea derivatives as efficient guanylating agents both in solution 1 and on solid support. 2 Thermal decomposition of N-arylthioureas gives aryl isothiocyanates. 3 Oxidation of arylthioureas with lead tetraacetate 4 or iodic acid 5 affords arylcyanamides. Thioureas condense with a-halocarbonyl compounds to afford 2-amino-1,3-thiazoles. 6 Benzothiazoles can be prepared from arylthioureas in the presence of bromine. 7 Solid-phase Biginelli pyrimidine synthesis 8 and synthesis of imidazolone derivatives 9 using resin-bound thioureas have been reported. The uses of thioureas to make 1,3-thiazines, 10 1,3-diazines, 11 1,3-quinazolines 12 and 1,2,4-triazines 13 were also described recently.Synthetic approaches to thioureas have been long investigated. 14 Well-known routes to substituted thioureas (Scheme 1) involve reactions of (i) anilines with sodium 15 or ammonium thiocyanate 16 in the presence of strong acids (TFA or concentrated HCl); (ii) aroyl isothiocyanates with amines followed by basic hydrolysis; 17 (iii) silicon tetraisothiocyanate with primary and secondary amines; 18 (iv) unsubstituted thioureas with primary alkyl amines at 170-180°C; 19 (v) isothiocyanates with ammonia or amines; 20 (vi) primary amines with carbon disulfide in the presence of mercury acetate and aqueous ammonia; 21 and (vii) disubstituted cyanamides with hydrogen chloride and LiAlHSH 22 or hydrogen sulfide in the presence of ammonia. 23 Mono and N,N-disubstituted thioureas were also prepared on solid support from Fmoc-isothiocyanate with subsequent deprotection. 9 Scheme 1Acylthioureas are valuable starting materials for numerous transformations: acylthioureas were used for the preparation of four-, 24 five-, 25 six-25c,26 and seven-27 membered heterocyclic ring systems. N,N-Dialkyl-N¢-acyl(aroyl)thioureas are efficient ligands for the separation and refinement of platinum group metals (Pd, Rh, Ru, Ir, and Os). 28 Acylthiourea derivatives have been patented as antidiabetic, 29 antiarthritic, 30 antineoplastic, 31 and anticoagulant 32 agents and for treatment of cognitive problems 33 and prostate disorder. 34 Herbicidal, 35 fungicidal, 35 bactericidal, 35 insecticidal 36 and plant growth regulator activities have also been reported.Common routes to acylthioureas are presented in Scheme 2. Acylthioureas can be prepared by (i) reaction of aminothiocarbonylimidoyl chlorides with potassium thiocyanate followed by hydrolysis; 37 (ii) acylation of N,N-disubstituted thioureas; 38 (...

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confidence: 99%

Synthesis of Mono- and N,N-Disubstituted Thioureas and N-Acylthioureas

Katritzky¹,

Kirichenko²,

Rogovoy³

et al. 2004

Synthesis

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“…The absence of color in freshly prepared solutions showed that there was no oxidation of the crystals during storage or manipulation. Purpurogallin, prepared according to the methods of EVANS and DENN (5) and sublimed in vacuo, was bright orange and melted at 184-185~ (10~ heating rate). Aqueous solutions of purpurogallin were prepared by diluting 0.300 mg/ml methanolic stock solutions.…”

Section: Methodsmentioning

confidence: 99%

The interaction of oxidation products of pyrogallol with poly-L-lysine. A model oxidative beer haze

Abrash

1977

Carlsberg Res. Commun.

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OFKey words: beer haze, lysozyme, oxidation, poly-L-lysine, PVP, pyrogallol Iodate oxidation of pyrogallol at pH 4 produces an agent capable of precipitation poly-L-lysine and lysozyme. This substance is neither purpurogallin nor one of its oxidation products. The solubility of the poly-L-lysine precipitate in 6M-guanidine hydrochloride and in 1M-NaOH indicates that hydrogen bonding is responsible for precipitation. While the oxidized pyrogallol solutions do not contain tannins detectable by the method of CHAPON, polyvinylpyrollidone (PVP) does prevent precipitation. Once formed, the precipitate does not redissolve in PVP. The pyrogallol oxidation products have no effect on the lysine-free polypeptide poly-N(5) hydroxyethyl-L-glutamine.

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“…A purpurogalina (2,3,4,6-tetrahidroxibenzociclohepten-5-ona, 8) é uma benzotropolona natural, que desde o século XIX vem sendo sistematicamente estudada. 24 Ocorre naturalmente como uma aglicona associada a vários glicosídeos, 25 podendo também ser obtido em grande quantidade de várias espécies de carvalhos (Quercus spp) através da noz ou casca, 26 sendo também facilmente produzida através de reações sintéticas [27][28][29] e enzimáticas (catalase ou peroxidases). 30,31 Um dos primeiros relatos na literatura sobre esse composto é datado de 1869 no qual Aimé Girard tratou com agentes oxidantes o pirogalol e observou a formação de uma substância vermelha, a qual denominou de purpurogalina e cuja fórmula descreveu como sendo C 20 H 16 O 9 .…”

Section: Purpurogalina E Derivadosunclassified

Biological Activity of Purpurogallin and its Derivatives

Silva¹,

Câmara²

2021

Rev. Virtual Quim.

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Purpurogallin is an extensively functionalized compound with a benzotropolone nucleus attached to an 1,2,3-trihydroxylated-benzene of natural origin, found originally in the walnut of the species Quercus spp, responsible for several biological activities, including anticancer activities, anti-inflammatory, antioxidant, antimicrobial, enzyme inhibitor and cytoprotection. The present review intends to address the relevance for further biological studies of purpurogallin and its derivatives.A purpurogalina é um composto de origem natural encontrado na noz da galha de espécies de Quercus spp, que possui um núcleo benzotropolona, sendo extensivamente funcionalizada com estrutura 1,2,3-trihidroxiladabenzenóide, que pode ser a responsável por diversas atividades biológicas, dos quais tem-se as atividades anticancerígena, anti-inflamatória, antioxidante, antimicrobiana, inibidor enzimático e citoprotetora. A presente revisão pretende abordar a relevância para estudos biológicos mais aprofundados da purpurogalina e de seus derivados.

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Organic Oxidations by Iodic Acid

Cited by 37 publications

References 0 publications

Synthesis of Mono- and N,N-Disubstituted Thioureas and N-Acylthioureas

Synthesis of Mono- and N,N-Disubstituted Thioureas and N-Acylthioureas

The interaction of oxidation products of pyrogallol with poly-L-lysine. A model oxidative beer haze

Biological Activity of Purpurogallin and its Derivatives

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