54598-91-3Relevant academic research and scientific papers
PROCESS FOR PREPARING SUBSTITUTED PENTACENES
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Page/Page column 32-33; 8; Sheet 3, (2008/12/08)
The invention relates to a process of preparing substituted pentacenes, to novel pentacenes prepared by this process, to the use of the novel pentacenes as semiconductors or charge transport materials in optical, electrooptical or electronic devices inclu
(Nitroaryl)sulfinyl-Substituted Allenes. Novel and Convenient Propargyl Alcohol Synthons in 4 + 2 Cycloaddition Chemistry
Padwa, Albert,Bullock, William H.,Norman, Bryan H.,Perumattam, John
, p. 4252 - 4259 (2007/10/02)
(Nitroaryl)sulfinyl-substituted allenes are conveniently prepared by treating propargyl alcohol or methyl 3-hydroxy-2-butynoate with a (nitroaryl)sulfenyl chloride and triethylamine.These activated allenes undergo 4 + 2 cycloaddition across the C1C2 α-bond.The initially formed allylic sulfoxide readily undergoes a 2,3-sigmatropic rearrangement to produce a stable sulfenate ester that is easily cleaved with thiophilic reagents.The dienophilic reactivity of the (nitroaryl)sulfinyl-substituted allene is much greater than the corresponding propargyl alcohol, and the cycloaddition also proceeds with high regioselectivity.The Diels-Alder reaction of propadiene with Danishefsky's diene affords meta-substituted benzyl alcohols in high yield.Reaction of the more highly activated methyl 2--2,3-butadienoate with Danishefsky's diene followed by treatment of the resulting sulfenate ester with triethyl phosphite produces substituted phthalides in excellent yield.The (2,4-dinitrophenyl)sulfinyl-substituted allene was found to react smoothly with a variety of nitrones to give sulfenate esters of isoxazolidines.These allenyl sulfoxides correspond to formal equivalents of propargyl alcohol, which itself is too unreactive to undergo Diels-Alder chemistry or 1,3-dipolar cycloaddition with nitrones or nitrile oxides.
Quinones,10. - Synthesis of 3-tert-Butyl-5,8-dimethyl-1,10-anthraquinone
Setiabudi, Frans,Boldt, Peter
, p. 1272 - 1279 (2007/10/02)
The title compound 3f is a novel isolable 1,10-anthraquinone which is stabilized only by alkyl groups.Despite of the shielding of the meso position 3f reacts very fast with water and oxygen to give 3-tert-butyl-1-hydroxy-5,8-dimethyl-9,10-anthraquinone (4f).
Ring-chain tautomerism as a factor in the reaction between Grignard reagents and substituted phthalides
Smith,Wikman
, p. 2603 - 2611 (2007/10/04)
With phthalide two equivalents of Grignard reagent react rapidly in a reaction which could not be controlled to give stepwise addition. In contrast, 3,3- and 4,7-disubstituted phthalides react with only one equivalent of organometallic reagent. The primary addition product formed from one equivalent each of phthalide and Grignard reagent exists in a ring-chain tautomerism whose position is controlled by the interaction between the substituents present in the phthalide and the alkyl group introduced by the Grignard reagent. With substituted phthalides, ring opening of the primary addition product is prevented by these interactions and thus a second equivalent of Grignard reagent does not react. In the absence of substituents, ring opening and the reaction of a second equivalent occurs. Somewhat related effects appear to exist in the reaction between Grignard reagents and phthalic anhydride and in the dehydration of substituted phthalyl alcohols to their corresponding phthalans.
