Isocamphanone in synthesis of 3-alkyl- and 6-alkyl-substituted camphor derivatives

On the interaction of isocamphanone with butyllithium, 2-butyl-5,5,6-trimethylbicyclo[2.2.1]heptan-endo-2-ol is formed stereospecifically. As a result of skeletal rearrangements of carbonium ions taking place in the course of the reaction, the Ritter reaction of this tertiary alcohol with acetonitrile and benzonitrile has given endo-3-butyl-1,7,7-trimethylbicyclo[2.2.1]hept-exo-2-ylacylamines and endo-6-butyl-1,7,7-trimethylbicyclo[2.2.1]hept-2-ylacylamines. Institute of Physical Organic Chemistry, Academy of Sciences of the Belorussian SSR, Minsk. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 807–812, November–December, 1988.     

Regioselective synthesis of 6-alkyl- and 6-prenylpolyhydroxyisoflavones and 6-alkylcoumaronochromone derivatives

The palladium-catalyzed coupling reaction of 6-iodoisoflavone, prepared from 3'-iodoacetophenone derivative, with 2-methyl-3-butyn-2-ol gave 6-alkynylisoflavone derivative, which was hydrogenated to give 6-alkylhydroxyisoflavone (luteone hydrate) (2). Dehydration of 2 gave 2',4',5,7-tetrahydroxy-6-prenylisoflavone (luteone) (1). Wighteone hydrate (3) was also synthesized from 6-iodotris(benzyloxy)isoflavone in a similar manner. 6-Alkyl-4'5,7-trihydroxy-coumaronochromone (4) was synthesized by oxidative cyclization of 2 with o-chloranil.     

Three-component synthesis of methyl 6-alkyl-3-cyano-2-halopyridine-4-carboxylates

A procedure has been developed for the synthesis of methyl 6-alkyl-3-cyano-2-halopyridine-4-carboxylate by three-component reaction of 4-oxoalkane-1,1,2,2-tetracarbonitriles with hydrogen halides in methanol.     

Chemoselective synthesis and spectral studies of N-thiocyanatoacetyl derivatives of 3-alkyl-2,6-diarylpiperidin-4-ones

A series of N–thiocyanatoacetyl derivatives of 3–alkyl–2,6–diarylpiperidin–4–ones has been synthesized by the reaction between the N–chloroacetyl derivatives of the respective piperidin–4–ones and the ambident thiocyanate nucleophile. The synthesized compounds have been characterized through FT–IR, ¹H, ¹³C, ¹H–¹H COSY, ¹H–¹³C COSY and NOESY spectra. The spectral data reveal the conformational priority of the six-membered heterocyclic ring.     

Facile synthesis of isocampholenic acids by the rearrangement of camphor derivatives

A variety of substituted isocampholenic acid derivatives were prepared by rearrangement of the camphor skeleton of a variety of tertiary alcohols derived from ketopinic acid. The reaction was highly reliable and retained the stereochemical information from the camphor scaffold. This rearrangement represents an efficient way to prepare synthetically useful isocampholenic acids. Mechanistic experiments show that a short-lived carbocation is implicated in the reaction.     

New synthesis of 4-alkyl-3-cyanocoumarins

A new procedure has been developed for the synthesis of 4-alkyl-6,8-dibromo-7-hydroxy-2-oxo-2H-chromene-3-carbonitriles by bromination of 2-amino-4-alkyl-4H-chromene-3-carbonitriles with bromine in acetic acid, followed by hydrolysis.     

A convenient synthesis of 3-alkyl-2,3-dihydro-2,4-dioxo-6-phenyl-, 3-alkyl-2,3-dihydro-4-oxo-6-phenyl-2-thioxo-, and 3-alkyl-2-arylimino-2,3-dihydro-4-oxo-6-phenyl-4H-1,3-thiazines

The reactions of 1-alkylamino-1-alkylthio-3-phenylpropene-3-thiones 3 with thiophosgene and phosgene in toluene, followed by treatment of the reaction mixture with triethylamine gave 3-alkyl-2,3-dihydro-4-oxo-6-phenyl-2-thioxo- 4 , 3-alkyl-2,3-dihydro-2,4-dioxo-6-phenyl-4H-1,3-thiazines 5 , respectively in good to excellent yields. Similarly treatment of compounds 3 with N-arylimidoyl dichloride in benzene at room temperature gave 3-alkyl-2-arylimino-2,3-dihydro-4-oxo-6-phenyl-4H-1,3-thiazines 6 in excellent yields. The reactions of compounds 3 with oxalyl chloride in toluene gave also 5 in good yields.     

A synthesis of 2-alkyl-3-furoic acids

An efficient synthesis of 2-alkyl-3-furoic acids has been developed. Addition of the lithium dianion of 4-oxo-2-phenylthiobutanoic acid ethylene acetal to aldehydes followed by acid-catalyzed cyclization produces furan products in high yield.     

New method of synthesis of 3-alkyl-4-piperidones

A new method is presented for the synthesis of 3-substituted 4-piperidones by alkylation of lithium derivatives of 4-(-phenylethylimino) piperidines using alkyl halides.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 372–374, March, 1986.     

Solid-phase synthesis of 3-alkyl-2-arylamino-3,4-dihydroquinazolines

The solid-phase synthesis of 3-alkyl-2-arylamino-3,4-dihydroquinazolines using an N-Fmoc-β-amino-2-nitrobenzenepropanoic acid scaffold is described. The resin-bound scaffold was reductively alkylated with aldehydes or ketones after Fmoc deprotection, followed by reduction of the nitro group with tin(II) chloride. Subsequent cyclization of the 1,3-diamine intermediates with aryl isothiocyanates in the presence of 1,3-diisopropylcarbodiimide (DIC) afforded the desired products in high purity with moderate to good yield after trifluoroacetic acid (TFA) cleavage.     

Fluorination of 2-alkyl-substituted oxanes. The synthesis and purification of perfluoro(2-alkyl-substituted oxane)s

Five kinds of 2-alkyl-substituted oxanes like 2-ethyloxane, 2-n-propyloxane, 2-iso-propyloxane, 2-n-butyloxane and 2-n-amyloxane were fluorinated electrochemically to give the corresponding perfluoro(2-alkyloxane)s. The perfluoro(2-alkyloxane)s were obtained in good yields from these starting materials together with isomeric perfluoro(2-alkyloxolane)s, perfluoro(2-alkyl-5-methyloxolane)s and perfluoro(dialkyl ether)s. The purification of the perfluoro(2-alkyloxane)s which contained small amounts of isomeric perfluoro(2-alkyloxolane)s was successfully achieved by recovering the former unreacted after treating these mixture with anhydrous aluminum chloride at 150 /sR 160 °C during /sR 48 hrs in order to convert the latter into the easy-separable perfluoro(2,5,5- trichloro-2-alkyloxolane)s. Small quantities of new perfluoro(5,5-dichloroalkanoyl chloride)s were also among the chlorination products. The spectroscopic data as well as the physical properties of these new fluorination products, and perfluoro(2,5,5-trichloro-2-alkyloxolane)s and perfluoro(5,5-dichloroalkanoyl chloride)s are presented.     

2-Acylimino-3-alkyl-3H-thiazoline derivatives: one-pot, three-component condensation synthesis of novel β-turn mimics

One-pot, three-component condensation of aroylthiourea, primary amine and α-halocarbonyl derivatives for the synthesis of 2-acylimino-3-alkyl-3H-thiazoline derivatives is described. This method is useful for simultaneously incorporating diverse functional groups at four positions in the 3H-thiazoline skeleton to obtain β-turn tripeptide mimics.     

An efficient synthesis of optically pure α-alkyl-β-azido- and α-alkyl-β-aminoalanines via ring opening of 3-amino-3-alkyl-2-oxetanones

N-Boc-α-alkylserine β-lactones on ring opening with sodium azide provide N-Boc-α-alkyl-β-azidoalanines, as N-protected amino acids are suitable for direct incorporation into peptides. N-Boc-α-alkyl-β-azidoalanines can be transformed by catalytic hydrogenation into the corresponding N-Boc-α-alkyl-β-aminoalanines.     

1－芳酰基－3－烷基－6－羟基－6－芳基富烯的合成

１－芳酰基－３－烷基－６－羟基－６－芳基富烯的合成焦纶基,董育斌,马玉道（山东大学应用化学研究所,济南,２５０１００）关键词富烯,二茂铁,芳酰化,合成前文［１］曾报道过甲基锂、苯基锂与６,６－二烷基富烯加成物的芳酰化。为进一步探讨取代环戊二烯负离子的...     

A new synthesis of 3-alkyl-6-alkylthio-1,2,4-triazolo[3,4-b]1,3,4-thiadiazoles

4-Amino-5-R-1,2,4-triazole-3-thiones react with alkyl(alkylaryl)thiocyanates in polyphosphoric acid to give the title compounds.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 230–231, January, 1993.     

Automated liquid-liquid extraction workstation for library synthesis and its use in the parallel and chromatography-free synthesis of 2-alkyl-3-alkyl-4-(3H)-quinazolinones

An automated liquid-liquid extraction workstation has been developed. This module processes up to 96 samples in an automated and parallel mode avoiding the time-consuming and intensive sample manipulation during the workup process. To validate the workstation, a highly automated and chromatography-free synthesis of differentially substituted quinazolin-4(3H)-ones with two diversity points has been carried out using isatoic anhydride as starting material.     

N-Lithium derivatives of aliphatic amines in the synthesis of 1-alkyl-2-phenyldiazene 2-oxides

Magnesium derivatives of aliphatic amines containing -hydrogen atoms, in contrast to t-BuNHMgBr, do not form phenylaliphatic diazene oxides upon reaction with nitrobenzene, but rather reduce it to azobenzene and azoxybenzene. Asymmetric diazene oxides are formed when the magnesium derivatives are replaced by lithium derivatives. The reaction of t-BuNHLi with dimethylnitramine gives 1,3,5-trimethyl-1,3,5-triazacyclohexane.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1452–1454, June, 1991.