Oxidation of 3-carene with mercuric acetate

Summary The oxidation of 3-carene with mercuric acetate was studied. The oxidative acetylation of 3-carene with mercuric acetate leads to a less complex mixture of products than oxidation with lead tetraacetate. The main products are p-mentha-l,5-dien-8-ol and, in smaller amount, p-isopropenyltoluene.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 466–475, March, 1965     

Photosensitized Oxygenation of Abieta-7,9(11)-dien-13β-ol

Dehydration of abiet-8-ene-7β, 13β-diol (ibozol, 1 ) leads to abieta-7,9(11)-dien-13β-ol ( 2 ) which aromatizes slowly to the known abieta-8,11,13-triene ( 3 ). Photosensitized oxygenation of the heteroannular diene 2 yields a mixture from which three compounds were identified; abiet-7-ene-9α, 11α, 13β-triol ( 4 ), abieta-8,11,13-trien-7-one ( 5 ), and abieta-8,11,13-trien-7α-ol ( 6 ).     

Cyclization and rearrangement of diterpenoids. III. Synthesis of isoagatholactone and methyl spongia-13(16),-14-dien-19-oate

The synthesis of isoagatholactone has been effected by the successive oxidation of (14R)-isoagath-12-en-15-ol with selenium dioxide and manganese dioxide. Methyl spongia-13(16),14-dien-19-oate has been obtained by the cyclization of methyl lambertianate with 100% sulfuric or fluorosulfonic acid.     

Oxidation Reactions of Azines. 10. Synthesis, Structure, and Oxodihydroxylation of 3-Hydroxymethyl-1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine

It has been established that oxidation of a mixture of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and dicyanomethane or formaldehyde with manganese dioxide gives 3-hydroxymethyl-1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, the structure of which was confirmed by X-ray structural analysis. Some oxidative conversions by potassium permanganate of the product formed and its esters have been studied. These included lactamization, aromatization, and oxodihydroxylation.     

Selenium dioxide oxidations of dialkyl-3H-azepines: the first synthesis of 2-azatropone from oxidation of 2, 5-Di-tert-butyl-3H-azepine

Oxidation reactions of 2,5- and 3,6-di-tert-butyl-3H-azepines (1 and 2) with selenium dioxide (SeO(2)) were performed. The oxidation of 1 with SeO(2) gave 3-tert-butyl-7,7-dimethyl-4-oxo-octa-2,5-dienal 3 in 36% yield, 4-tert-butyl-5-(3,3-dimethyl-2-oxo-butylidene)-1, 5-dihydro-pyrrol-2-one 4 in 13% yield, 2, 6-di-tert-butyl-2-pyridinecarbaldehyde 5 in 12% yield, and 4, 7-di-tert-butyl-2H-azepin-2-one (2-azatropone) 6 in 6% yield, respectively. Oxidation of 2 with SeO(2) gave 2, 2-dimethyl-1-[2-(5-tert-butyl)-pyridyl]propanol 7 in 55% yield, and 3,6-di-tert-butyl-2H-azepine 8 in 5% yield, respectively. We found that selenium dioxide oxidation of 1 affords 4-oxo-octa-2,5-dienal 3 by a new ring cleavage reaction of 1, and we described the first synthesis of 2-azatropone 6 from this oxidation of 1. In the case of 2, pyridylpropanol 7 was obtained as the major product. We now report in detail result of these oxidation reactions, which have led to the synthesis of a novel azatropone derivative.     

Synthesis of 2-carbethoxybenzofuran derivatives

A mixture of 3-formyl and 3-acetoxymethyl derivatives is formed in the oxidation of 2-carbethoxy-3-methyl-7-ethylbenzofuran with selenium dioxide. Reduction with lithium aluminum hydride gives 2,3-dihydroxymethyl derivatives, which are converted to 2,3-diformyl derivatives by successive oxidation. A number of derivatives of 3-methyl-7-ethylbenzofurancarboxylic acid were obtained.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 756–759, June, 1987.     

Synthesis of 2,3-diformyl-5-ethylbenzofuran and its derivatives

A mixture of 3-formyl and 3-acetoxymethyl derivatives is formed in the oxidation of 2-carbethoxy-3-methyl-5-ethylbenzofuran with selenium dioxide. Reduction of the products with lithium aluminum hydride gives the corresponding 2,3-dihydroxymethyl derivatives, which are converted to 2,3-diformyl derivatives by successive oxidation by the Fetizon method and with manganese dioxide. The corresponding benzofuro[2, 3-d]pyridazines were synthesized by reaction of 2-carbethoxy-3-formyl-5-ethylbenzofuran with hydrazine hydrate.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 893–895, July, 1982.     

Free radicals: XXVIII. Reaction of 2,4,6-triphenylpyranyl with (diacetoxy-λ3-iodanyl)benzene

The major product of the reaction of 2,4,6-triphenylpyranyl with (diacetoxy-λ³-iodanyl)benzene in acetonitrile and acetone was 2,4,6-triphenylpyrylium acetate. Analogous reaction in isopropyl alcohol resulted in the formation of methane, carbon dioxide, 1,3,5-triphenylpent-2-ene-1,5-dione, 2-benzoyl-3,5-diphenylfuran, 1,3,5-triphenylpenta-2,4-dien-1-one, and a small amount of 2,4,6-triphenylpyrilium acetate.     

1-取代-4,5-二(4-氯苯基)咪唑的合成和结构表征

合成了6种1-取代-4,5-二(4-氯苯基)咪唑.以对氯苯乙酸和氯苯为原料,经Friedel-Crafts酰基化反应、二氧化锡氧化、与多聚甲醛和乙酸铵环合制备了中间体4,5-二(4-氯苯基)咪唑(5),5再经取代得到3个1-取代-4,5-二-(4-氯苯基)咪唑类化合物6a-c.6a再分别与液体胺经亲核取代反应得到3个1-取代乙酰胺类-4,5-二-(4-氯苯基)咪唑类化合物7a-c.目标化合物结构用核磁共振氢谱和红外光谱进行了表征.     

Zur Photochemie des Benzfurazans

Irradiation of benzofurazan ( 1 ) in benzene solution yields the azepine derivative 3 as the main photoproduct. Addition of methanol in the dark to the irradiated benzene solution of 1 results in the isolation of 3 together with a new product, methyl-1-cis, 3-cis-N-(4-cyano-buta-1, 3-dien-1-yl)-carbamate (1-cis, 3-cis- 2 ). Irradiation of 1 in methanol solution gives a mixture of the stereoisomeric methyl N-(4-cyano-buta-1, 3-dien-1-yl)-carbamates, from which the 1-trans, 3-cis isomer of 2 could be isolated in pure form. The observed photoproducts are formed via the reactive intermediates a , a nitrile-(nitrile oxide), and c , a nitrene, neither of which was isolated.     

Cyclization and rearrangement of diterpenoids. III. Synthesis of isoagatholactone and methyl spongia-13(16),-14-dien-19-oate

The synthesis of isoagatholactone has been effected by the successive oxidation of (14R)-isoagath-12-en-15-ol with selenium dioxide and manganese dioxide. Methyl spongia-13(16),14-dien-19-oate has been obtained by the cyclization of methyl lambertianate with 100% sulfuric or fluorosulfonic acid.Institute of Chemistry, Academy of Sciences of the Moldavian SSR, Kichinev. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 725–731, November–December, 1984.     

Synthesis of perfluoroalkyl-substituted 4,5-dihydro-3H-pyrazolo[4,3-a]phenazines and tetrahydroimidazo[4,5-e]indazoles

Oxidation of 1-aryl-3-perfluoroalkyl-6,7-dihydro-1H-indazol-4(5H)-ones with selenium dioxide in the presence of sulfuric acid in glacial acetic acid, followed by treatment of 6,7-dihydro-1H-indazole-4,5-diones thus obtained with an equimolar amount of o-phenylenediamine in ethanol or with a mixture of 4-fluorobenzaldehyde and ammonium acetate in acetic acid, gave 3-aryl-1-perfluoroalkyl-4,5-dihydro-3H-pyrazolo-[4,3-a]phenazines and 6-aryl-2-(4-fluorophenyl)-8-perfluoroalkyl-1(3),4,5,6-tetrahydroimidazo[4,5-e]indazoles, respectively.     

Catalysis of reaction between ozone and 4-hydroxytoluene in acetic anhydride

Kinetics and products of 4-hydroxytoluene oxidation with ozone-air mixture in the presence of transition metal acetates as catalysts have been studied. Main steps of the catalytic series have been considered, and a mechanism of redox catalysis has been proposed which conforms to the experimental data and enables control over the direction, depth, and selectivity of the oxidation. Only manganese(II) acetate has been found to exhibit high catalytic activity in the presence of catalytic amounts of mineral acids. Manganese(II) acetate largely suppresses electrophilic reaction of ozone with the aromatic ring, so that the main reaction direction is oxidation of the methyl group with formation of 4-acetoxybenzyl acetate as the major product (62.6%) and 4-acetoxybenzylidene diacetate as a minor one (10.2%).     

Säurekatalysierte Umlagerung von 4-Allyl-cyclohex-2-en-1-olen; Beispiele für ladungskontrollierte [3s, 4s]-Umlagerungen von cyclischen Allylkationen

The acid-catalysed rearrangement of the cyclohex-2-en-1-ols 15 , d₃- 15 , 16 , 17 and 19 , the cyclohexa-2,5-dien-1-ols 20 and 21 , and also the allyl alcohols 22 and 23 (Scheme 3), using 98-percent sulfuric acid/acetic anhydride 1:99 at room temperature, was investigated. From the rearrangement of 4-allyl-4-phenyl-cyclohex-2-en-1-ol ( 15 ), with reaction times greater than 2 hours a single product is obtained, 4-allyl-biphenyl ( 50 ) in 33% yield (Scheme 9). With reaction times below 2 hours the acetate 53 from 15 was isolated, and this could be converted into 50 . The reaction of 2′,3′,3′-d₃-15 in Ac₂O/H₂SO₄ lead to 1′,1′,2′-d₃-50 (Scheme 11). The rearrangement of 4-allyl-4-methyl-cyclohex-2-en-1-ol (16) (Scheme 14) yielded 39% of the corresponding acetate 60 and 30% of 4-allyl-toluene ( 6 ), which also resulted by a rearrangement of 60 under the reaction conditions. These rearrangements are all [3s,4s]-sigmatropic reactions, which proceed via the cyclohexenyl cation a (Scheme 12, R = C₆H₅, CH₃). In Ac₂O/H₂SO₄ the allyl-cyclohexadienes primarely formed subsequently undergo dehydrogenation to yield the benzene derivatives 6 , 50 and d₃- 50 . From the rearrangement of 4,4-diphenyl-cyclohex-2-en-1-ol ( 19 ) at 0° a reaction mixture is obtained which consists of the acetate 55 , 2,3-diphenyl-cyclohexa-1,4-diene ( 57 ) and o-terphenyl ( 56 ) (Scheme 10). Both 55 and 57 are converted under the reaction conditions to o-terphenyl ( 56 ). No 4-(1′-methylallyl)-biphenyl is obtained from the rearrangement of 4-crotyl-4-phenyl-cyclohex-2-en-1-ol ( 17 ). In this case, apart from the corresponding acetate 64 , a single product 5-(1′-acetoxyethyl)-1-phenyl-bicyclo[2.2.2]oct-2-ene ( 65 ) (Scheme 16) was obtained; under the reaction conditions the acetate 64 rearranges to 65 . The rearrangement of 4-allyl-4-phenyl-cyclohexa-2,5-dien-1-ol ( 20 ) gives, as expected, not only 4-allyl-biphenyl ( 50 ) but also 2- and 3-allyl-biphenyl ( 51 and 52 ) and biphenyl (Scheme 13). 4-Benzyl-4-methyl-cyclohexa-2,5-dien-1-ol (syn- and anti- 21 ) gave in Ac₂O/H₂SO₄ at 10° as rearrangement products 93% of 2-benzyltoluene ( 97 ) and 7% of 4-benzyl-toluene ( 98 ) (Scheme 21). Hence [1,4]-rearrangements in cyclohexadienyl cations, seems to occur only to a limited extent. The alicyclic alcohols 22 and 23 (Scheme 18) gave, in Ac₂O/H₂SO₄, as main product the corresponding acetates 73 and 75 , as well as small amounts of olefins 74 and 76 formed by dehydration i.e. [3,4]-rearrangements occur in these systems. Also no [3,4]-rearrangements were observed in solvents reactions of either 4,4-dimethyl-hepta-1, 6-dien-3-yl tosulate (79; see Scheme 19) or its corresponding alcohol 24.     

On the First Marine Stigmastane Sterols and Sterones Having a 24,25-Double Bond. Isolation from the Sponge Stelletta sp. of Deep Coral Sea

The sponge Stelletta sp. (Astrophorida, Stellettidae), collected at ?700 m in the Coral Sea, is shown to contain sterones and sterols of the stigmastane type with a C(24)?C(25) bond for which there is no precedent in the sea. Structure elucidation of the second abundant of these steroids, stigmasta-4,24(25)-dien-3-one ((+)- 1 ), is based on 1D and 2D NMR spectra and chemical transformation to acetate (?)- 5 . Stigmasta-4,24(25)-diene-3,6-dione ((?)- 3 ), present in trace amounts in the sponge, was obtained in sufficient quantity for NMR study by oxidation of the also present, inseparable, and abundant 4:1 mixture of stigmasta-5,24(25)-dien-3β-ol ( 6 ) and its 5,6-dihydro derivative 7 (Scheme 1). This oxidation also afforded the ketone analogues (+)- 8 and (+)- 9 , which could be separated, thus making structure elucidation possible. The 6β-hydroxystigmasta-4,24(25)-dien-3-one ((+)- 4 ), also present in trace amounts in the sponge, was obtained in sufficient amount for NMR study, together with its C(6) epimer (+)- 11 , by hydroperoxidation of (+)- 8 followed by deoxygenation (Scheme 2). The last trace steroid of the sponge, stigmasta-4,6,24(25)-trien-3-one ((?)- 2 ), was structurally elucidated using limited NMR data and comparison with the other stigmastanes. These stigmastanes, as the only steroids of this sponge, are likely to function as stabilizers of its cell walls; their phytosteroid structure, for a sponge which lives in the dark of deep waters, suggest origin through a complex food chain, possibly followed by bioelaboration in the sponge.     

Oxidationsreaktionen methyl-substituierter 2,1,3-Benzothiadiazole und 2,1,3-Benzoselenadiazole mit Selen-dioxid

Oxidation Reactions of Methyl Substituted 2,1,3-Benzothiadiazoles and 2,1,3-Benzoselenadiazoles with Selenium Dioxide The synthesis 5–8 by oxidation of 4-methyl-( 1 ),5-methyl( 2 ), 5,6-dimethyl-2,1,3-benzoselenadiazole ( 3 ), and 5,6-dimethyl-2,1,3-benzothiadiazole ( 4 ), respectively, with selenium dioxide as well as their spectroscopic properties are described.     

Fumigant and repellent activities of essential oil extracted from Artemisia dubia and its main compounds against two stored product pests

The major chemical constituents of the essential oil extracted from Artemisia dubia wall. ex Bess. (Family: Asteraceae) were found as terpinolene (19.02%), limonene (17.40%), 2,5-etheno[4.2.2]propella-3,7,9-triene (11.29%), isoelemicin (11.05%) and p-cymene-8-ol (5.93%). Terpinolene and limonene were separated as main components from the essential oil. The essential oil showed fumigant toxicity against Tribolium castaneum and Liposcelis bostrychophila with LC₅₀ values of 49.54 and 0.74 mg/L, respectively. The essential oil and isolated compounds of A. dubia showed repellency activities against both insects. Terpinolene and limonene showed the fumigant toxicity against T. castaneum. Terpinolene showed obvious fumigant toxicity against L. bostrychophila. The results indicated that the essential oil of A. dubia had potential to be developed into natural insecticides for controlling stored product pests.     

A model for triterpene side-chain synthesis. 2

A bicyclic model for 17-keto derivatives of triterpenes, trans -1,6-dimethyl-2-methoxybicyclo[4.3.0] nonan-7-one (1), was used to explore side-chain construction concurrent with oxidation at C-8 (triterpene C-16). Oxidation of methylene derivative 2 with selenium dioxide gave β alcohol 14, and borohydride reduction of the corresponding ketone (15) led to the α epimer 16. Each allylic alcohol (14 and 16) reacted stereospecifically with phenylsulfenyl chloride to give, respectively, diastereoisomeric sulfoxides 20 and 19. The latter yielded a conjugate base that was methylated selectively to give sulfoxide 21. Desulfuration of 21 with trimethylphosphite generated the ethylidene α alcohol 22, and following PDC oxidation, E enone 25.This enone was a minor product from an alternative synthesis beginning with ethylidene derivative 3. Treatment of 3 with selenium dioxide followed by PDC gave the isomeric Z enone 24 as the major product. Reaction of 24 with lithium bis-4-methyl-3-pentenylcuprate proceeded by a facial-selective conjugate addition to the euphane CD model 26. The E isomer 25, under similar conditions, gave only an unresolved mixture. These results are compared with similar steroid reactions reported by Trost and Schmuff¹¹.     

Oxidation studies on Andrographolide

Jones oxidation of Andrographolide (1), gave mixture of three products (3-dehydroandrographolide (5), 3,19-bis dehydroandrographolide (6) and 19-dehydroandrographolide (7). Tritylation of andrographolide at C19-OH resulted to products 8 and diene 9, which can be converted to its acetate 10 and oxidation product 11.     

Zur Oxydation von 2,3-Dimethylchinoxalin und 2,4-Dimethylchinazolin mit Selendioxid

Summary The primary oxidation products of 2,3-dimethylquinoxaline with selenium dioxide are 3-methylquinoxaline-2-carbaldehyde, 1,3-dihydro-1,3-dihydroxyfuro[3,4-b]quinoxaline and quinoxaline-2-carboxylic acid. 3-Methylquinoxaline-2-carboxylic acid can be obtained in a second oxidation step only. 2,4-Dimethylquinazoline is dehydrogenated by selenium dioxide to the heterocyclic stilbene derivative8. Confirmation of structure of8 is given by NMR-spectroscopy.