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Aromatic C–H allylation of N-sulfonyl ketimines with allyl alcohol or allyl phenyl ether as an allyl source is catalyzed by a cationic iridium complex. The presence of a catalytic amount of a pyridine derivative was found to be essential for the reaction. In contrast, direct C–H allylation of ketimines derived from benzophenone derivatives and p-methoxyaniline with allyl phenyl ether proceeded in the absence of pyridine derivatives.

We report a novel, efficient, and easily prepared substrate/precursor family of Schiff bases of various glycine esters with 2-hydroxybenzophenone, and their use for the synthesis of amino acids in quantitative yields. The Michael addition of the substrates to methyl acrylate gave two different types of product (cyclic or chain), depending on the nature of the base. Also, we demonstrated that one of the new substrates could be involved in an asymmetric version of the alkylation reaction (70% ee).

Xanthone, thioxanthone, fluorenone, benzophenone, 2-benzoylpyridine, dibenzofuran, and dibenzothiophene were deprotonated using a base prepared in situ from MCl2·TMEDA (M = Zn or Cd; TMEDA = N,N,N′,N′-tetramethylethylenediamine) and lithium 2,2,6,6-tetramethylpiperidide in a 1:3 ratio, as demonstrated by subsequent iodolysis. The different aryl halides were involved as partners in the N-arylation of pyrrolidin-2-one. In the presence of copper(I) iodide and tripotassium phosphate, and using dimethyl sulfoxide as solvent, the reactions could be performed in yields ranging from 40 to 70%. Most of the products were tested for their antimicrobial, antifungal, antioxidant, and cytotoxic (MCF-7) activity.

In order to identify new antiretroviral agents, a series of novel uracil derivatives have been synthesized. Optimized conditions for coupling of Weinreb amides with aromatic Grignard reagents allow the convenient preparation of key benzophenone intermediates in high yields and purities. The use of a modified silyl Hilbert–Johnson reaction affords the target compounds under mild conditions.

Ynamides reacted with benzophenone imines in the presence of triflic imide as a catalyst. Ynamides bearing a sulfonamide moiety gave the corresponding 2-amino-3,4-dihydroquinolines selectively in good to high yields. In contrast, yne-carbamates gave the corresponding α,β-unsaturated amidines exclusively. These methods permit simple preparation of sterically crowded polysubstituted quinolines and α,β-unsaturated amidines.

A general and practical synthetic protocol for the direct transformation of unreactive C(sp3)–H bonds to C(sp3)–CN bonds has been developed. The homolytic cleavage of the C–H bond is initiated by photo-excited benzophenone, and the resulting carbon radical subsequently reacts with tosyl cyanide to afford the corresponding nitrile in a highly efficient manner. The present methodology is widely applicable to various starting materials including ethers, alcohols, amine derivatives, alkanes, and alkylbenzenes. This newly developed C–H cyanation protocol provides a powerful tool for selective one-carbon elongation for the construction of architecturally complex molecules.

A new four-step approach for the synthesis of anticancer agentcombretastatin A-4 (CA-4) has been developed. The method includesthe Colvin rearrangement of the benzophenone derivative phenstatinto the key diarylalkyne followed by stereoselective semi-reductionto CA-4 in good overall yield.

Photoaffinity tags can be incorporated easily into peptoids and congeners by the Ugi and Passerini multicomponent reactions. Products related to photo-methionine and photo-leucine can be accomplished by diazirine-containing building blocks. The same protocols can be used to synthesize derivatives with benzophenone photo cross-linkers.

An efficient synthesis of the dopamine D 1 selective full agonist dihydrexidine has been achieved in high yields and requiring no chromatographic separations via a facilitated intramolecular Henry cyclization of a (nitropropyl)benzophenone and subsequent diastereomerically selective reduction of the resulting tricyclic nitroalkene.

A new protocol for palladium-catalyzed Buchwald-Hartwig amination of aryl chlorides and bromides with benzophenone imine as ammonia surrogate is described. The suggested reaction conditions are mild and may therefore be applied to a variety of sensitive starting materials.

New photoactivatable analogues of glutathione disulfide (GSSG) bearing new benzophenone-like photophores were synthesized by using an improved coupling reaction.

Double lithiation of 2-alkyl-3H-quinazoline-4-thiones, at nitrogen and at the a-hydrogen of the 2-alkyl group (Me, Et, nPr), has been achieved with n-butyllithium at -78 0C in anhydrous THF under nitrogen. Reactions of the dilithium reagents obtained with various electrophiles (iodomethane, iodoethane, 1-bromobutane, D2O, benzaldehyde, 4-anisaldehyde, 2-butanone, cyclohexanone, benzophenone, phenyl isothiocyanate, tetraisopropylthiuram disulfide) gave the corresponding modified 2 substituted 3H-quinazoline-4-thiones 4-22 in excellent yields.

A mild and efficient procedure for the selective cleavage of N-benzhydryl protecting group of beta-lactams is described. The protected 2-azetidinones 4, precursors of carbapenems, were treated with a stoichiometric amount of N-bromosuccinimide and a catalytic amount of bromine under sun light irradiation in CH2Cl2-H2O mixture at 20 degreesC for 3 hours. The N-benzhydrol intermediates 6, which could be isolated, were then hydrolyzed with p-TsOH in aqueous acetone to furnish beta-lactams 7 and benzophenone quantitatively.

3-Methyl-1H-quinoxaline-2-thione (1) has been doubly lithiated, at nitrogen and at the 3-methyl group, with n-butyllithium at –78 °C in THF. The resulting dilithium reagent obtained reacts with a variety of electrophiles (iodomethane, iodoethane, 1-bromobutane, D2O, benzaldehyde, anisaldehyde, 2-hexanone, cyclohexanone, benzophenone, phenyl isothiocyanate) to give the corresponding modified 3-substituted 1H-quinoxaline-2-thiones 4–13 in high yields. Similarly, double lithiation of 3-ethyl- (4) and 3-propyl-1H-quinoxaline-2-thiones (5), followed by reaction with some electrophiles gave the corresponding modified 3-substituted derivatives 15–19 in high yields. Treatment of some of the products with trifluoroacetic acid in dichloromethane at room temperature led to formation of substituted 2,3-dihydrothieno[2,3-b]quinoxalines in good yields.

Nickel(II) complexes of Schiffs bases derived from (S)-o-[(N-benzyl]prolyl)amino]benzophenone [N-(2-benzoylphenyl)-1-benzylpyrrolidine-2-carboxamide] (BBP) and glycine or alanine have been used for asymmetric synthesis of fluoro (S)-phenylalanines and (S)-α-methyl(phenyl)alanines. Large selectivity (>90%) is observed for the alkylation of both complexes.

Aryl- and alkylhydrazones 1 of alkyl ketones and propanal are transformed to 1-chloroalkylazo compounds 2 with tert-butyl hypochlorite. Compounds 2 react with antimony(V) chloride or aluminum(III) chloride to give 1-aza-2-azoniaallene salts 3 as reactive intermediates, which are intercepted as 3H-1,2.4-triazolium salts 5 with nitriles. In most cases these salts rearrange spontaneously to form the corresponding 1H-triazolium salts 6. Benzophenone arylhydrazone 1x reacts with ter-butyl hypochlorite

Higher imine esters 1a-h and 7a-b of amino acids and dipeptides are prepared in 68-91 % yield by saponification of the benzophenone Schiff base methyl esters 3a-d and 6 using phase-transfer techniques followed by O-alkylation with an alkyl halide. The procedure occurs with retention of configuration at the α-carbon except with phenylglycine derivatives

The title compounds are prepared by an efficient one-pot reaction using readily available phosphonates and S-alkyl carbonchloridothioates. The reaction is capable of variation in the phosphonate and especially in the carbanochloridothioate components

Heteropoly acids are effective solid catalysts for the thioacetalization of carbonyl compounds. Tungstophosphoric acid (H 3 PW 1 2 O 4 0 ), was found to be an effective and a highly selective catalyst for the thioacetalization of aldehydes, ketones and for the transthioacetalization of acetals, acylals and O,S-acetals which proceeded in excellent yields in the absence of solvent. The catalyst has also been successfully applied to the chemoselective conversion of α- or (3-diketones and a β-keto ester into the corresponding dithioacetals. Sterically hindered carbonyl compounds such as camphor and benzophenone were also converted to their corresponding thioacetal; in refluxing petroleum ether in 89-94% yields, Surprisingly, anthrone was reduced to anthracene in 91% yield.

1-(2,6-Dihydroxyphenyl)-1-alkanones, natural products identified from insects and from medicinal plants, are readily prepared from 1,3-cyclohexanedione and appropriate carboxylic acids. The final step involves aromatization using mercuric acetate

Sodium percarbonate in trifluoroacetic acid has been found to be an effective reagent for the Baeyer-Villiger oxidation of ketones to esters. The scope and limitations of the reaction were explored

Carbonyl compounds are smoothly and rapidly acetalized by treatment with alcohols, in anhydrous acetonitrile, in the presence of polystyryl diphenyl phosphine - iodine complex as catalyst. Open and cyclic acetals, including 1,3-dioxolanes, 1,3-oxathiolanes, and 1,3-dithiolanes, of miscellaneous aldehydes and ketones have been successfully prepared in this way. The isolation of the product is very easily performed, by simple filtration of the polymer-linked phosphine oxide which is formed in the reaction.

Chloropyrazine is regioselectively metalated by lithium amides in tetrahydrofuran to give 3-chloro-2-lithiopyrazine. The reaction of this lithio derivative with electrophiles can either be performed in situ (with the electrophile, e. g., chlorotrimethylsilane, present in the mixture already during metalation), i. e., by the "equilibrium shift" procedure, or with the solution of the preformed lithio derivative, i. e., by the "accumulation" procedure. With aldehydes and benzophenone, the "accumulation" procedure affords 3-chloro-2-(1-hydroxyalkyl)pyrazines in good yields. The secondary alcohols thus obtained can be oxidized to 2-acyl-3-chloropyrazines with manganese(IV) oxide and these ketones can be converted into 3-acyl-2-aminopyrazines by reaction with ammonia in ethanol; cyclization of 3-chloro-2-(2-methoxybenzoyl) pyrazine using pyridine hydrochloride at 210°C affords 10-oxo-10H-[1] benzopyrano[2,3-b]pyrazine (1,4-diazaxanthone) in high yield. 3-Chloro-2-formylpyrazine is obtained by reaction of the lithio derivative with ethyl formate and 3-chloropyrazine-2-carboxylic acid by reaction with carbon dioxide.

Preparation de l'oxydant et etude de son utilisation lors de l'oxydation d'alcools et de thiols

Synthese de benzylimines d'aldehydes et de cetones par reaction de benzaldehyde, cinnamaldehyde, acetaldehyde, acetophenone, benzophenone et acetone avec la benzylamine sur alumine en absence de solvant