Hasan Seçen

A new and stereospecific synthesis of conduritol-F and conduritol-Bs

Abstract A new and stereospecific synthesis for conduritol-F has been developed starting from transbenzenediacetate 5 and oxepine-benzeneoxide 8 where the oxygen functionalities were introduced in both cases by photooxygenation; suitable ring opening reactions gave the desired conduritol-F. Acid-catalyzed ring opening reaction of 11 in aceticanhydride gave conduritol-F and conduritol-B in a ratio of 2:1.

Synthesis of haloconduritols from an endo-cycloadduct of furan and vinylene carbonate

Abstract A method for preparing haloconduritols having a conduritol-A construction is described. A mixture of endo- and exo-cycloadduct derivatives prepared from the Diels–Alder reaction of furan and vinylene carbonate was converted into diacetate derivatives by hydrolysis (K2CO3/MeOH) followed by acetylation (Ac2O/pyridine). Boron trihalide (BBr3 or BCl3)-assisted ring-opening of the endo-diacetate in CH2Cl2 at −78°C gave (1α,2α,3β,6β)-6-halogeno-4-cyclohexene-1,2,3-triol 1,2-diacetate from which the corresponding triacetate was prepared by acetylation (AcCl). trans-Esterification of the triacetate (MeOH/HCl) afforded (1α,2α,3β,6β)-6-halogeno-4-cyclohexene-1,2,3-triol (X=Br or Cl). BF3-Assisted ring-opening of the endo-diacetate in CH2Cl2 gave (1α,2α,3β,6β)-6-chloro-4-cyclohexene-1,2,3-triol 1,2-diacetate by means of halogen exchange.

Alternative and Straightforward Synthesis of Dopaminergic 5-Methoxy-1,2,3,4-tetrahydronaphthalen-2-amine

Abstract 5-Methoxy-1,2,3,4-tetrahydronaphthalen-2-amine was synthesized from 2-naphthoic acid in six steps with an overall yield of 27%. Following the reaction sequence, bromination, esterification, substitution with NaOMe in the presence of CuI, the Birch reduction, Curtius rearrangement, and hydrogenolysis afforded biologically active title compound 5-methoxy-1,2,3,4-tetrahydronaphthalen-2-amine as hydrogen chloride salt.

Stereospecific Synthesis of Conduramine-F4 and Conduritol-F (Leucanthemitol)

Abstract Stereospecific synthesis of Conduramine-F4 and Conduritol-F has been achieved by fully stereospecific cyloaddition of singlet oxygen to cyclohexadiene ketal 1 followed by reductive extrusion of one oxygen atom. The obtained monoepoxide 3 has been smoothly opened to conduritol-F 4 and conduramine-F4 6 by water and ammonia, respectively.

A novel and stereospecific synthesis of conduritol-A

A new and stereospecific synthesis for conduritol-A has been developed starting from cyclohexa-1,4-diene where hydroxy groups have been introduced by classical KMnO4-oxidation followed by photo-oxygenation; suitable ring-opening reactions gave the desired conduritol-A.

A Novel Synthesis of Conduritol-C and Conduritol-E via p-Benzoquinone

Abstract A new and stereospecific synthesis for Conduritol-C 8 and Conduritol-E 13a has been developed starting from p-benzoquinone 1. 1,4-oxygen functionalities were introduced in both synthesis by the reduction of dibromo p-benzoquinone 2 with NaBH4. 2,3-oxygen functionalities were introduced by KMnO4 oxidation of 4 for Conduritol C 8. Oxidation of 3 with m-chloroperbenzoic acid gave 9. Acid-catalyzed ring opening reaction of 9 gave 10a which leads to Conduritol-E.

A Novel Synthesis of DL-proto-, and DL-vibo-Quercitol via 1, 4-Cyclohexadiene

Abstract Photooxygenation of 1, 4-cyclohexadiene 3 followed by reduction with LiAlH4 or thiourea gave (25/1)-cyclohex-3-ene-triol 7a. trans-Hydroxylation of triol 7a with three different methods afforded both of proto-quercitol la and vibo-quercitol 2a.

Photooxygenation of azidoalkyl furans: catalyst-free triazole and new endoperoxide rearrangement.

Photooxygenation of azidoalkyl furans has revealed both a novel triazole formation method and a unique endoperoxide rearrangement. The key step of this method is a 3 + 2 cycloaddion of the azide to the endoperoxide intermediate. The reduction of the peroxide bond and two subsequent C-C bond cleavages provide a triazole having a newly formed carboxylic acid functionality. The reactions are clean and efficient with yields ranging from 60% to 90%.

Evidence for the formation of a new five-membered ring cyclic allene: Generation of 1-cyclopenta-1,2-dien-1-ylbenzene

Treatment of 1-(2-iodocyclopent-1-en-1-yl)benzene (13), dissolved in benzene, with potassium t-butoxide resulted in the formation of 1-(2-phenylcyclopent-1-en-1-yl)benzene (15) and 1-cyclopent-1-en-1-ylbenzene (5) in a ratio of 1:1.

A short synthesis of 4-amino-3-hydroxybutyric acid (GABOB) via allyl cyanide

Abstract4-Amino-3-hydroxybutyric acid was synthesized from allyl cyanide in four steps in an overall yield of 38%. Ultrasonically promoted epoxidation of allyl cyanide with m-chloroperoxybenzoic acid giving oxiranylacetonitrile was used as a key step.