Withm-chloroperbenzoic Acid Research Articles

Epoxidized polybutadiene as a thermal stabilizer for poly(3-hydroxybutyrate). II. Thermal stabilization of poly(3-hydroxybutyrate) by epoxidized polybutadiene

Epoxidized polybutadiene (EPB) was prepared by polybutadiene (PB) withm-chloroperbenzoic acid (MCPBA) in homogeneous solution. EPB was blended with poly(3-hydroxybutyrate) (PHB) up to 30 wt% by solution-precipitation procedure. The thermal decomposition of PHB/EPB blends was studied by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and differential thermal analysis (DTA). The thermograms of PHB/EPB blends contained a two-step degradation process, while that of pure PHB sample exhibited only one-step degradation process. This degradation behavior of PHB/EPB blends, which have a higher thermal stability as measured by maximum decomposition temperature and residual weight, is probably due to crosslinking reactions of the epoxide groups in the EPB component with the carboxyl chain ends of PHB fragments during the degradation process, and the occurrence of such reactions can be assigned to the exothermic peaks in their DTA thermograms.

Epoxidized polybutadiene as a thermal stabilizer for poly(3-hydroxybutyrate). I. Effect of epoxidation on the thermal properties of polybutadiene

Polybutadiene (PB) was epoxidized to various extens withm-chloroperbenzoic acid (MCPBA) in homogeneous solution. The thermal properties of the epoxidized PBs were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). As a result of epoxidation the glass transition temperature (T g) of PB increased by approximately 0.8°C for each 1 mol% of epoxidation. The thermal decomposition of the epoxidised PBs occurred in twostep process, while that of PB exhibited apparent one-step degradation process.

Oxidations of 12-Deoxy-, 12-Hydroxy-, 12-Methoxy-, and 12-Hydroxy-13-methoxy-podocarpa-8,11,13-triene Derivatives

Methods for the oxidation of the aryl ring of derivatives of podocarpic acid have been examined. Oxidation of methyl 12-hydroxypodocarpa-8,11,13-trien-19-oate (2) with phenyliodonium diacetate in various solvents gives 8β-substituted dienones. An 8β-chloro dienone is formed during oxidation of the phenol (2) with t-butyl hypochlorite. Oxidation of (2) with dimethyldioxiran gives mainly the 7-ketone (13) but also affords the novel ε-lactone (26), while treatment with ruthenium tetraoxide also affords products of benzylic oxidation. Oxidation of methyl podocarpa-8,11,13-trien-19-oate (4) with m-chloroperbenzoic acid affords a B-ring lactone (29) and, unexpectedly, a 6α-chloro 7-ketone (30). The action of cerium(IV) ammonium nitrate on (2) gives nitro derivatives rather than oxidation products. Oxidation of methyl 12-hydroxy-13-methoxypodocarpa-8,11,13-trien-19-oate (22) with m-chloroperbenzoic acid gives a low yield of a 7-oxo derivative (17) while treatment with ozone gives an unusual α,β-unsaturated γ-lactone (31), the hydroxy lactone (33), the unsaturated keto ester (34), and the substituted furan (35). Oxidation of (22) with Fremy"s salt gives products of ring B oxidation. The structure of (31) has been confirmed by X-ray crystallography.

Novel synthesis of 10-membered cyclic bis-ethers from 4-(N-alkylanilino)but-2-yn-1-ols 1

A number of symmetrical 10-membered cyclic bis-ethers 5a–f are synthesized in a single step in good yields from the reaction of 4-(N-alkylanilino)but-2-yn-1-ols 3a–f with m-chloroperbenzoic acid in dichloromethane at room temperature during 8 h.

Oxidation of fluoroalkyl-substituted allylic alcohols: a synthesis of fluorinated ?,?-epoxyketones

Fluoroalkyl-substituted allylic alcohols are readily and selectively oxidized at the hydroxyl group with the Swern or Dess-Martin reagents to give α,β-unsaturated ketones, and on treatment withm-chloroperbenzoic acid ortert-butyl hydroperoxide they are oxidized to the corresponding epoxyalcohols. The latter are oxidized by Swern or Dess-Martin reagents at the hydroxyl group to α,β-epoxyketones, which form hydrates stable under the conditions of isolation.

Natural product chemistry, Part 132: Synthesis and oxidative cyclisation of 1,3-dihydroxy-10-methyl-4-(3-methylbut-2-enyl)-9(10H)-acridinone (glycocitrine-II)

Reaction of 1,3-dihydroxy-10-methyl-9(10H)-acridinone (1) and 1-bromo-3-methylbut-2-ene (mol. ratio 1:1) in tetrahydrofuran at 20°C in the presence of alumina gave prenylacidinones2 (glycocitrine-II) and8 and the diprenylacridinone9; with an excess of 1-bromo-3-methylbut-2-ene, the prenyldihydropyranoacridinones12 and13 were formed. Oxidation of glycocitrine-II (2) withm-chloroperbenzoic acid furnished the furanoacridinone5 and the pyranoacridinone6; dehydration of the latter compound gave noracronycine (10).

Hydroxylation of menthols and cineoles withm-chloroperbenzoic acid

Reaction of menthols and cineoles withm-chloroperbenzoic acid afforded tertiary, secondary, and primary alcohols, some of which were natural products having potent plant growth regulatory activity or were mammlianm metabolies.

ChemInform Abstract: HYDROXYLATION OF NATURAL PRODUCTS WITH M‐CHLOROPERBENZOIC ACID. 2. HYDROXYLATION OF DAMMARANE TYPE TRITERPENES WITH M‐CHLOROPERBENZOIC ACID

Chemischer InformationsdienstVolume 16, Issue 20 Natural Products ChemInform Abstract: HYDROXYLATION OF NATURAL PRODUCTS WITH M-CHLOROPERBENZOIC ACID. 2. HYDROXYLATION OF DAMMARANE TYPE TRITERPENES WITH M-CHLOROPERBENZOIC ACID M. TORI, M. TORISearch for more papers by this authorR. MATSUDA, R. MATSUDASearch for more papers by this authorY. ASAKAWA, Y. ASAKAWASearch for more papers by this author M. TORI, M. TORISearch for more papers by this authorR. MATSUDA, R. MATSUDASearch for more papers by this authorY. ASAKAWA, Y. ASAKAWASearch for more papers by this author First published: May 21, 1985 https://doi.org/10.1002/chin.198520324Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume16, Issue20May 21, 1985 RelatedInformation

Synthesis of precursors of C4 and C5 cumulenones

Bicyclo[2.2.l]hept-5-en-2-one was condensed with 2,2-dimethyl-1,3-dioxan-4,6-dione in the presence of titanium tetrachloride/pyridine to yield 5-(bicyclo[2.2.1]hept-5'-en-2'-ylidene)-2,2-dimethyl-1,3- dioxan-4,6-dione (6a) which on pyrolysis at 520-560�/0.01 mm gave acetone, carbon dioxide, cyclopentadiene and butatrienone. In the same way 5-(7'-oxabicyclo[2.2.1]hept-5'-en-2'-ylidene)-2,2- dimethyl-1,3-dioxan-4,6-dione (6b) was prepared from 7-oxabicyclo[2.2.1]hept-5-en-2-one and on pyrolysis at 570�/0.01 mm it gave acetone, carbon dioxide, furan and butatrienone. Alkylation of 2-trimethylsiloxybicyclo[2.2.1]hepta-2,5 with phenylthiomethyl chloride with titanium tetrachloride as catalyst followed by condensation with 2,2-dimethyl-1,3-dioxan-4,6-dione gave an endo/exo mixture of 5-(3'-phenylthiomethylbicyclo[2.2.1]hept-5'-en-2'-ylidene)-2,2-dimethy 1-1,3-dioxan- 4,6-dione. The structure of the endo isomer was established by X-ray crystallography. Oxidation of the phenylthiomethyl compound with m-chloroperbenzoic acid yielded the sulfoxide which was converted by boiling in carbon tetrachloride into 5-(3'-methylenebicyclo[2.2.l]hept-5'-en-2'-ylidene)- 2,2-dimethyl-1,3-dioxan-4,6-dione (8). Preliminary studies on the fragmentation of compound (8) have shown that at 450�/0.01 mm it is converted into acetone, carbon dioxide and products showing ketene absorption at 2140 cm-1. The formation of pentatetraenone has not been established with certainty. The 3'-phenylsulfonylmethyl, phenylselenyl and methyl derivatives of (6a) are also described.

ChemInform Abstract: OXIDATION OF 2‐METHYL‐4,5,6,7‐TETRAHYDROBENZOFURAN WITH M‐CHLOROPERBENZOIC ACID

Chemischer InformationsdienstVolume 14, Issue 51 Isocyclic Compounds ChemInform Abstract: OXIDATION OF 2-METHYL-4,5,6,7-TETRAHYDROBENZOFURAN WITH M-CHLOROPERBENZOIC ACID S. B. GINGERICH, S. B. GINGERICHSearch for more papers by this authorP. W. JENNINGS, P. W. JENNINGSSearch for more papers by this author S. B. GINGERICH, S. B. GINGERICHSearch for more papers by this authorP. W. JENNINGS, P. W. JENNINGSSearch for more papers by this author First published: December 20, 1983 https://doi.org/10.1002/chin.198351165AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume14, Issue51December 20, 1983 RelatedInformation

Bridgehead Hydroxylation of Tricycloalkanes withm-Chloroperbenzoic Acid

Bridgehead Hydroxylation of Tricycloalkanes with<i>m</i>-Chloroperbenzoic Acid

ChemInform Abstract: UNEXPECTED OXIDATION OF A NITROXIDE ALCOHOL WITH M‐CHLOROPERBENZOIC ACID

Chemischer InformationsdienstVolume 6, Issue 7 Heterocyclic Compounds ChemInform Abstract: UNEXPECTED OXIDATION OF A NITROXIDE ALCOHOL WITH M-CHLOROPERBENZOIC ACID J. A. CELLA, J. A. CELLASearch for more papers by this authorJ. A. KELLEY, J. A. KELLEYSearch for more papers by this authorE. F. KENEHAN, E. F. KENEHANSearch for more papers by this author J. A. CELLA, J. A. CELLASearch for more papers by this authorJ. A. KELLEY, J. A. KELLEYSearch for more papers by this authorE. F. KENEHAN, E. F. KENEHANSearch for more papers by this author First published: February 18, 1975 https://doi.org/10.1002/chin.197507275Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume6, Issue7February 18, 1975 RelatedInformation