2-(Trialkoxysilylalkylthio)ethyl vinyl sulfides

Conclusions Trialkoxysilylalkanethiols (CH₃O)₃Si(CH₂)_nSH (n=1–3) react with divinyl sulfide at 100–110° to give 2-(trialkoxysilylalkylthio)ethyl vinyl sulfides (CH₃O)₃Si(CH₂)_nS (CH₂)₂SCH=CH₂ in high yield. The reactivity of the trialkoxysilylalkanethiols decreases with increase in the number of CH₂ groups between the S and Si atoms. A second molecule of the organosilicon thiol acids adds with difficulty to divinyl sulfide to give the diadduct.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 197–199, January, 1977.     

Synthesis of [2-(vinyloxy)ethyl]uracil and [2-(allyloxy)ethyl]uracil

A synthesis is reported for N¹-mono- and N¹,N³-disubstituted uracil derivatives containing a terminal carbon-carbon double bond in the side-chain. Alkylation of vinyl 2-chloroethyl ether by uracil potassium salts leads to a mixture of 1-[2-(vinyloxy)ethyl] and 1,3-di[2-(vinyloxy)ethyl] derivatives while treatment of 2,4-bis(trimethylsilyloxy)pyrimidines by vinyl 2-chloroethyl ether leads exclusively to N¹-monosubstituted products. Alkylation of cytosine by this chloroether gave 1-[2-(vinyloxy)ethyl]cytosine. The synthesis of 1-[2-(allyloxy)ethyl]uracil derivatives was carried out by treatment of uracil potassium salts by 1-(allyloxy)-2-(p-toluenesulfonyloxy)ethane.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 393–397, March, 1993.     

Psilocin analogs II. Synthesis of 3-[2-(dialkylamino)ethyl]-, 3-[2-(N-methyl-N-alkylamino)ethyl]-, and 3-[2-(cycloalkylamino)ethyl]indol-4-ols

Structural alteration of the N^b-substituents of psilocin (3-[2-dimethylamino)ethyl]indol-4-ol) ( 12a ) has led to a number of compounds containing known pharmacophoric groups. Further, it is hoped that the subtle changes in the nature of these substituents may lead to a clearer understanding of the structure-activity relationships of the 4-hydroxytryptamine hallucinogens.     

Synthesis of aryl 2-(2-imidazolyl)ethyl ketones

The Claisen-Schmidt condensation of 1-(triphenylmethyl)-2-imidazolecarboxaldehyde with acetophenones yielded 1-aryl-3-[1-(triphenylmethyl)-2-imidazolyl]propen-1-ones 7 . Selective catalytic hydrogenation over platinum of 7 furnished 1-aryl-3-(2-imidazolyl)-1-propanones 8 . An alternate synthesis of 8 started with sodium borohydride reduction of 7 to give allylic alcohols, 1-aryl-3-[1-(triphenylmethyl)-2-imidazolyl]-2-propen-1-ols 10 , which were rearranged by hot aqueous sodium to 8 . Acid hydrolysis of 8 provided the title compounds and triphenylmethanol.     

Novel reactivity of 2-(chloromethoxy)ethyl acetate

2-(Chloromethoxy)ethyl acetate reacts with alcohols in the presence of silver carbonate to produce 2-(alkoxymethoxy)ethyl acetates and bis(alkoxy)methanes. A mechanism which involves neighbouring group participation of a chloromethyl ether oxygen atom is proposed to account for the formation of the latter products.     

Experimental and computational studies on zwitterionic (E)-2-(1-(2-(4-methylphenylsulfonamido)ethyliminio)ethyl) phenolate

The Schiff base compound (E)-2-(1-(2-(4-methylphenylsulfonamido)ethyliminio)ethyl) phenolate has been synthesised and characterized by IR, UV–Vis, and X-ray single-crystal determination. Ab initio calculations have been carried out for the title compound using the density functional theory (DFT) and Hartree–Fock (HF) methods at 6-31G(d) basis set. The calculated results show that the DFT/B3LYP and HF can well reproduce the structure of the title compound. Using the TD-DFT and TD-HF methods, electronic absorption spectra of the title compound have been predicted and a good agreement with the TD-DFT method and the experimental ones is determined. Molecular orbital coefficient analyses reveal that the electronic transitions are mainly assigned to n → π* and π → π* electronic transitions. To investigate the tautomeric stability, optimization calculations at B3LYP/6-31G(d) level were performed for the NH and OH forms of the title compound. Calculated results reveal that the OH form is more stable than NH form. In addition, molecular electrostatic potential and NBO analysis of the title compound were performed at B3LYP/6-31G(d) level of theory.     

Synthesis and tautomerism of ethyl 2-(2-benzothiazolyl)-2-(6-purinyl)acetate and related compounds

Reaction of 6-chloro-9H-(2-tetrahydropyranyl)purine ( 2d ) with the sodium salt of ethyl benzothiazole-2-ace-tate ( 1 ) in dimethylformamide effects condensation of the two compounds (with loss of sodium chloride) to give the corresponding ethyl diarylacetate 4 (35%), present largely as an enol chelate tautomer. Isolated as a by-product is 6-(2-aminophenyl-1-thio)-9H-(2-tetrahydropyranyl)-purine (4%), formed via opening of the thiazole ring. Removal of the tetrahydropyranyl protective group from 4 occurs by treatment with p-toluenesulfonic acid in aqueous ethanol to produce ethyl benzothiazole-2-(6-purinyl)acetate (80%), existent largely as two enol chelate isomers. Spectral data for the various products are presented. An attempt to use 6-chloro-9-acetyl-9H-purine in place of 2d in the first reaction gives acetylation of 1 instead of condensation.     

LDA-catalyzed cycloisomerization of 2-(2-propynyloxy)ethyl iodides leading to 3-(iodomethylene)tetrahydrofurans

LDA catalyzes cycloisomerization of 2-(2-propynyloxy)ethyl iodides to give 3-(iodomethylene)tetrahydrofurans. The reaction is proposed to proceed through a mechanism involving exo-cyclization of an alkynyllithium intermediate and protonation of the resulting alkylidene carbenoid by the starting iodide. [reaction: see text]