A convenient one-pot preparation of 2-methyl-3-(phenylthio- methyl)quinolines from Morita-Baylis-Hillman adducts and their oxidation to the corresponding sulfones

A convenient one-pot preparation of 2-methyl-3-(phenylthiomethyl)quinolines from Morita-Baylis-Hillman adducts via conjugate addition of thiols followed by reductive cyclization with Fe/AcOH was developed. The 2-methyl-3-(phenylthiomethyl)quinolines were transformed into 2-methyl-3-(phenylsulfonylmethyl)quinolines via m-CPBA-mediated oxidation.     

A convenient entry to C2- and C3-substituted gulono-gamma-lactone derivatives from L-ascorbic acid

A convenient method to obtain unknown chiral C2- and C3-functionalized aldono-1,4-lactone derivatives starting from l-ascorbic acid, which would be valuable in the synthesis of derivatives of various pharmacologically active agents for structure-activity studies, is described. The practicality of this approach is demonstrated by the synthesis of a series of 5,6-O-isopropylidene-2-allyl-3-keto-l-galactono-gamma-lactone and 5,6-O-isopropylidene-3-allyl-2-keto-l-galactono-gamma-lactone derivatives using the thermal Claisen rearrangement of the corresponding 3-O- and 2-O-allyl derivatives of 5,6-O-isopropylidene-l-ascorbic acid, respectively, followed by stereospecific reduction to the corresponding alcohols. The synthetic steps are shown to be efficient, and enantiospecific, and they proceed with high yields.     

1,2,4-triazines. 1. A convenient synthesis of 4,5-dihydro-1,2,4-triazin-3-(2H)one and its 6-substituted derivatives

A facile synthesis of 4,5-dihydro-1,2,4-triazin-3-(2H)one (2a) from 5-methylthio-1,2,4-triazin-3-(2H)one (1a) with sodium borohydride is described. The reaction provides a convenient method for its 6-substituted derivatives (2b-h).     

A convenient preparation of functionalized 1,8-dioxygenated naphthalenes from 6-alkoxybenzocyclobutenones

An alternate route for the synthesis of naphthalene building blocks 1-4 has been developed, starting from readily available 6-alkoxybenzocyclobutenones. As thermolysis of a propynylbenzocyclobutenol only provided the naphthalene in low yield, allenyl-substituted benzocyclobutenols were investigated. The desired allenic precursors were prepared by a two-step procedure, which involved hydroxyl-directed reduction of the chloropropargylbenzocyclobutenols obtained from addition of lithiopropargyl chloride to the benzocyclobutenones. Thermolysis of the allenic alcohols gave the desired naphthalenes in good yields.     

A convenient preparation of 2-fluoro-3-alkoxy-1,3-butadienes

[reaction: see text] 1-Chloro-1-fluoro-2-methoxy-2-methylcyclopropane eliminates HCl on heating in quinoline solution above 50 degrees C to give 2-fluoro-3-methoxy-1,3-butadiene in high yield. If an alcohol is added to the reaction then a 2-fluoro-3-alkoxy-1,3-butadiene is obtained in high yield. The dienes give smooth 4 + 2 cycloaddition reactions.     

Spectral studies of semicarbazones derived from 3- and 4-formylpyridine and 3- and 4-acetylpyridine: crystal and molecular structure of 3-formylpyridine semicarbazone

Semicarbazones derived from 3- and 4-formylpyridine (H3FoPyS, H4FoPyS) and 3- and 4-acetylpyridine (H3AcPyS, H4AcPyS) were prepared and studied spectroscopically. Complete NMR assignments for these semicarbazones were made using DEPT135, as well as HMQC and HMBC heteronuclear correlation techniques. The crystal and molecular structures of H3FoPyS were determined.     

A modified and convenient method for the preparation of N-phenylpyrazoline derivatives

Ten new N-phenylpyrazoline derivatives have been synthesized in high yields by condensation of chalcones with phenylhydrazine in the presence of potassium carbonate in reflux conditions. The workup is simple and involves treatment with ice-cold water. As compared with the previous method a considerable increase in the reaction rate with better yields has been observed. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1032–1036, July, 2006.     

A convenient preparation of 2-haloenones from enones using phenylselenium halides

Enones can be converted in high yield to their corresponding 2-halo analogues by treatment with an excess of phenylselenium halide in methylene chloride/pyridine at 37°C.     

A convenient preparation of 2-thioxo-4(3H)-quinazolinones

A simple method is described for the preparation of 3-aryl-2-thioxo-4(3H)-quinazolinones (4) by the reaction of anthranilic acids and ammonium or triethylammonium N-aryl-dithiocarbamates in ethanol. The method is also applicable to the preparation of 3-ethyl-2-thioxo-4(3H)-quinazolinone.     

The reformatsky reaction of 1-acyl-3,5-dimethylpyrazoles. A convenient preparation of 4-amino-3-oxoalkanoic acid derivatives

The conversion of N-acylpyrazoles into β-keto esters was accomplished efficiently by the treatment with α-bromo esters and zinc dust. Using this Reformatsky reaction of N-acylpyrazoles, 4-(protected amino)-3-oxoalkanoic acid derivatives were conveniently prepared as the key intermediates in the synthesis of statines.     

A convenient method for the preparation of [1-2H]- and [1-3H]-terminal acetylenes

Conclusions A convenient one-step method has been proposed for the preparation of 1-isotope-substituted acetylenes based on the use of a phase transfer catalyst.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No, 8, pp. 1921–1922, August, 1985.     

A convenient synthesis of 2-hydrazinoethylphosphonic acid and derivatives

2-Hydrazinoethylphosphonic acid was prepared using a simple procedure involving Michael addition of hydrazine hydrate to diethyl ethenylphosphonate, followed by hydrolysis with hydrochloric acid. The product was converted into five- and six-membered heterocycles.     

A new convenient synthesis of 5-aryl-2-(arylamino)-1,3,4-oxadiazole derivatives

Electrical energy offers numerous benefits for conducting a synthesis, including increased reaction rates, yield enhancements and cleaner chemistries. 5-Aryl-2-(arylamino)-1,3,4-oxadiazoles were synthesised directly from acylthiosemicarbazide on the platinum electrode under controlled potential electrolysis in an undivided cell assembly in acetonitrile.