Dienes dioxides

Synonyms AI3-09068 AIDS-153 B 1266 1,4-Benzoquine Benzoquinone Benzo-l,4-quinone 1,4-Benzoquinone p-Benzoquinone BRN 0773967 Caswell No. 719C CCRIS 933 Chinone Cyclohexadienedione 1,4-Cyclohexadienedione 2,5-Cyclohexadiene-l,4-dione 1,4-Cyclohexa-diene dioxide 1,4-Dioxybenzene EINECS 203-405-2 EPA pesticide chemical code 059805 NCI-C55845 NSC 36324 Quinone 4-Quinone RCRA waste number U197 UN 2587 USAF P-220. 

Z,Z,Z)-Cyclo-octa-l,3,5-triene reacts with SO2 to give 9-thiabicyclo[4,2,l]nona-2,7-diene dioxide which was converted into 9-thiabicyclo[4,2,l]nona-2,4-diene dioxide. Thermal expulsion of SO2 had a free energy of activation lOkcalmol" greater for the latter dioxide than for the former dioxide so showing that linear extrusion of SO2 is favoured over non-linear extrusion or sequential bond cleavage. Photolysis of 1,2,5,6-tetramethylenecyclo-octane gave a mixture of the [3,3,2] propellane (230) and the tricyclodiene (74). ... 

EPM/EPDMcompounding pLASTOTffiRS, SYNTTiETIC - ETTTYLENE-PROPYLENE-DIENE RUBBER] (Vol 8) Tellurium dioxide [7446-07-3]... 

Sulfur dioxide acts as a dienophile ia the Diels-Alder reaction with many dienes (253,254) and this reaction is conducted on a commercial scale with butadiene. The initial adduct, sulfolene [77-79-2] is hydrogenated to a solvent, sulfolane [126-33-0] which is useful for selective extraction of aromatic hydrocarbons from... 

Reaction of myrcene and sulfur dioxide under pressure produces myrcene sulfone. This adduct is stable under ordinary temperatures and provides a way to stabilize the conjugated diene system in order to hydrate it with sulfuric acid. The myrcene sulfone hydrate produced is pyrolyzed in the vapor phase in order to regenerate the diene system to produce myrcenol [543-39-5] (50). 

The electrochemical conversions of conjugated dienes iato alkadienedioic acid have been known for some time. Butadiene has been converted iato diethyl-3,7-decadiene-l,10,dioate by electrolysis ia a methanol—water solvent (67). An improvement described ia the patent Hterature (68) uses an anhydrous aprotic solvent and an electrolyte along with essentially equimolar amounts of carbon dioxide and butadiene a mixture of decadienedioic acids is formed. This material can be hydrogenated to give sebacic acid. 

The methiodide of 2,5-dihydrothiophene (239) is transformed in high yield to Z)-l-(methylthio)buta-l,3-diene (240) on treatment with alkali (81AJC1017). The thermal cheletropic extrusion of sulfur dioxide from both cis and trans isomers of 2,5-dihy-drothiophene 1,1-dioxides is highly stereospecific. For example, c/5-2,5-dimethyl-2,5-dihydrothiophene 1,1-dioxide (241) yields ( , )-hexa-2,4-diene (242) and sulfur dioxide (75JA3666, 75JA3673). 

The facile addition of sulfur dioxide to buta-1,3-dienes provides a useful source of... 

Oxidation of the 3-hydroxy-A systenli with manganese dioxide in refluxing benzene affords a moderate yield of the corresponding 4,6-dien-3-one. These vigorous conditions also suffice to cleave the corticoid side chain (17a,21-dihydroxy-20-ketones) to give 17-keto steroids. ... 

Hydroxyandrosta-4,6-dien-3-one. A suspension of 42 g of crude androsta-4,6-diene-3j ,17j -diol in 2000 ml of chloroform is treated with 250 g of activated, manganese dioxide. The mixture is then shaken vigorously for 15 min in a stoppered flask. The mixture is filtered and the manganese dioxide washed well with chloroform in order to elute material which initially remains adsorbed on the solid phase. The filtrate is concentrated to a pale yellow, crystalline residue. Recrystallization from acetonitrile gives 38 g (90%) of 17/ -hydroxyandrosta-4,6-dien-3-one as plates mp 211-214°. 

Addition, acetic acid to bicyclo[2.2.1]-hepta-2,5-diene to give nortri-cyclyl acetate, 46, 74 1,2,3-benzothiadiazole 1,1-dioxide to cyclopentadiene, 47, 8 benzyne to tetraphenylcyclopentadie-none, 46,107 Br, F to 1-heptene, 46,10 carbon tetrachloride to olefins, 46, 106... 

In this case, the benzene dioxide 5 is obtained from a [2,2]paracyclophane diene by photooxygenation and rearrangement of the derived endoperoxide. 

The 6-substituted 1,4-dioxocins can be used to prepare other 6-substituted derivatives by simple functional group transformations.4,8,9 Especially interesting is the synthesis of the 4/7-4-oxo-2,3-dihydropyran-2-yl-substituted derivative 16 from l,4-dioxocin-6-carbaldehyde (15) by a cyclocondcnsation with Danishefsky s diene.9 Dehydrogenation of 16 yields 2 which can be isomerized to the corresponding isomeric. sr/i-benzene dioxide 3 (X = 4/f-4-oxopyran-2-yl), which is identical with and proved the structure of the naturally occurring antibiotic LL-Z 1220.10... 

Interestingly, benzonitrile oxide does not react with thiirene dioxide 19b even in boiling benzene, whereas the electron-rich diene l-piperidino-2-methyl-l, 3-pentadiene (177) does react under the same reaction conditions to give the expected six-membered [4 + 2] cycloadduct 178, accompanied by sulfur dioxide extrusion and 1,3-hydrogen shift to form the conjugated system 179175 (equation 70). 

Two attractive routes to thiolene oxide and dioxide are the diene-SO104 and diene-S02298 cycloadditions, respectively. These cycloadditions are highly stereoselective at both carbons of the diene systems and at sulfur (see equation 62 for specifics) which, in the case of sulfoxide formation, proceed via attack of triplet SO on the diene. Equation 112 shows an example of such a cycloaddition104. The overall yields are significantly improved by running the cycloadditions in the absence of oxygen and by the use of excess diene. 

Since sulfoxides and sulfones are versatile synthetic intermediates, and since in both the thiolene oxide and dioxides the reverse dethionylation114 ( — SO), and cheletropic extrusion of sulfur dioxide296, respectively, readily take place thermally, these cycloadditions are expected to find a useful place in organic synthesis. It should be kept in mind, however, that the retrograde SO-diene reaction and interconversion of the thiolene oxides compete effectively against SO extrusion on heating, and that diene isomerization accompanies the forward reaction (SO + diene). 

The trapping of both sulfines and sulfenes with dienes is probably the method of choice for the preparation of 3-thiene oxides and dioxides, respectively143,337. 

Thiophene 1,1-dioxide (61) is too unstable to isolate and dimerizes with loss of S02 to give 3a, 7a-dihydrobenzothiophene 1,1-dioxide (172) in 34%113. However, alkyl-substituted thiophene 1,1-dioxides can serve as dienes in the Diels-Alder reaction, since the aromatic properties of the thiophene nucleus are lost completely and the n-electrons of the sulfur atom are used for forming the bond with oxygen. The sulfones 173-178 are found to react with two moles of maleic anhydride at elevated temperature to give bicyclic anhydrides114. Thus, at high reaction temperature, S02 is split off to give cyclohexadiene... 

The reaction given here has been described before as a general reaction,2 and there can be a wide variety of alkyl, aryl, and halo substituents on the diene and phosphorus. Dibromophosphines are appreciably more reactive than dichlorophosphincs. If a free-radical catalyst is used instead of an inhibitor, the copolymers can be made in good yield.3 The 1,4-addition of dichloro-phosphines to 1,3-dienes is of theoretical interest because of its analogy to the well-known 1,4-addition of sulfur dioxide to 1,3-dienes. 

Thiepin-1,1-dioxide undergoes a number of chromium(0) mediated [6jt + 4jt] cycloaddition reactions with a range of 1,3-dienes. The intermediate adduct undergoes a Ramberg-Backlund rearrangement to form new benzannulated products <96JOC7644>. 

The hybrid cyclic pentayne 181 underwent Diels-Alder reaction with the electron-deficient diene tetrachlorothiophene 1,1-dioxide 192, but only at one of the two triple bonds of the 1,3-diyne moiety. This was followed by loss of SO2 to give the tetrachlorobenzannelated cyclotetradecenetetrayne 193 (Scheme 37) [18]. 

Mechanisms depending on carbanionic propagating centers for these polymerizations are indicated by various pieces of evidence (1) the nature of the catalysts which are effective, (2) the intense colors that often develop during polymerization, (3) the prompt cessation of sodium-catalyzed polymerization upon the introduction of carbon dioxide and the failure of -butylcatechol to cause inhibition, (4) the conversion of triphenylmethane to triphenylmethylsodium in the zone of polymerization of isoprene under the influence of metallic sodium, (5) the structures of the diene polymers obtained (see Chap. VI), which differ. both from the radical and the cationic polymers, and (6)... 

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