One-step RhCl3-catalyzed deprotection of acyclic N-allyl amides

A convenient one-step RhCl3-catalyzed deprotection of acyclic N-allyl amides is described. Preliminary mechanistic studies reveal that the key to the success of the one-step deprotection process is the dual function of RhCl3 in alcohol solvents. Reaction of RhCl3 with n-PrOH not only provides an active rhodium hydride species to catalyze isomerization of N-allyl amides to corresponding enamides but also generates a crucial catalytic amount of HCl to convert the enamides to deallylated amides through N,O-acetal exchange.     

A new synthetic method of α-amino acids from α-methoxyurethanes

Reaction of α-methoxyurethanes with phenylisocyanide gave the corresponding amides of α-amino acid in reasonable yields.     

Mild and Efficient Conversion of Nitriles to Amides with Basic Urea-Hydrogen Peroxide Adduct

The urea-hydrogen peroxide adduct, an inexpensive, stable and easily handled reagent has shown utility for mild and efficient transformation of nitriles into the corresponding aliphatic or aromatic amides. Reaction proceeds in aqueous acetone, within 0.5-2.5h, in the presence of catalytic amount of K₂CO₃, at room temperature.     

1,2-联烯基酮的合成与反应

1,2-联烯基酮可以通过2-丙炔基酮异构化反应,相应有机金属试剂中间体与酯、酰氯或酰胺的反应,[2,3]或[3,3]迁移反应,Wittig反应,消除反应,2,3-联烯醇氧化等方法合成。由于联烯酮上含有吸电子基团羰基,它可发生亲核加成、环加成、环化反应。     

Oxydation von nichtcyclischen Derivaten der Methylarsonigsäure

Oxidation of Noncyclic Derivatives of Methylarsonous Acid Reaction of methyldichloroarsine with alcohols and sec. amides yields esters, diamides and amidechlorides of methylarsonous acid. Oxidation with o-chloranil yields the corresponding derivatives of methylarsonic acid.     

Synthesis of novel S-neoglycopeptides from glycosylthiomethyl derivatives

Reaction of glycosylthiomethyl azides with amino acid and peptide derivatives containing aspartate and glutamate thio acids gave the corresponding glycosylthiomethyl amides in excellent yields. Another type of neoglycopeptides was obtained via reaction of glycosylthiomethyl bromide with cysteine and homocysteine containing peptide derivatives, thus affording the corresponding S-(glycosylthiomethyl) peptides.     

Quinazolines 1. Synthesis and chemical reactions of 6-chlorosulfonyl-quinazoline-2,4-diones

Treatment of quinazoline-2,4-dione and its symmetrical 1,3-dialkyl derivatives with chlorosulfonic acid gave the corresponding 6-chlorosulfonylquinazoline-2,4-diones. Reaction of the compounds obtained with nucleophilic agents (water, ammonia, aliphatic and cyclic amines) gave the corresponding free 2,4-dioxoquinazoline-6-sulfonic acids, 6-sulfamidoquinazoline-2,4-diones, and 2,4-dioxoquinazoline-6-sulfonic acid amides. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 420–427, March 2008.     

1,8-diazabicyclo[5.4.0]undec-7-ene (dbu): An effective base for the introduction of tbutyldimethylsilyl group in organic compounds.

Reaction of alcohols, thiols, amines, carboxylic acids, phenols, hydroquinones, ketoesters and amides with equimolecular amounts of t-butyldimethylchlorosilane and DBU, even in solvents other than dimethylformamide affords the corresponding t-butyldimethylsilyl derivatives in high yield.     

Oxidation and chlorination reactions of perfluoroketene-N,S-acetals

The paper presents the results of the investigation of oxidation and chlorination reactions of perfluoroketene-N,S-acetals. Oxidation reactions of perfluoroketene-N,S-acetals proved to be dependent on the nature of oxidizing agent and led to the formation of corresponding sulfone in the case of m-chloroperbenzoic acid or amides of α-H-perfluoroalkane carboxylic acids in the case of tert-butyl hydroperoxide or hydrogen peroxide. Reaction of 1-tert-butylsulfanyl-2,3,3,4,4,4-hexafluoro-1-[N-methyl,N-((S)-α-methylbenzyl)amino]-but-1-ene with sulfuryl chloride demonstrated the chlorination of perfluoroketene-N,S-acetals as a new approach in the synthesis of chiral α-chloro perfluoroalkane carboxylic acid amides.     

2-Ene-1,4-diols by dimerization of terminal epoxides using hindered lithium amides

[reaction: see text] Reaction of hindered lithium amides with readily available (enantiopure) terminal epoxides gives 2-ene-1,4-diols via carbenoid dimerization of the corresponding alpha-lithiated epoxides. D-Mannitol and D-iditol were synthesized using this method in three steps from (S)-tritylglycidyl ether.     

Regioselective hydroxysulphenylation of derivatives of allylicalcohols and amines

Reaction of manganic acetate with diphenyidisulplilde in dichloromethane-trifluoroacetic acid in the presence of allylic esters or amides of allylamine gives trifluoroacetoxysulphides and hence by ready hydrolysis vicinal hydroxysulphides. The regiochemical outcome can be controlled by selection of either an acetyl- or trifluoroacetyl derivative.     

Synthese und Konfiguration der mono- und dialkylsubstituierten Amide der diastereomeren 3-Amino-2,3-diphenylpropansäuren

Zusammenfassung Die Umsetzung des Cyclohexylamids, Dimethylamids und Morpholids der Phenylessigsäure mit Hydrobenzamid in Gegenwart von wasserfr. AlCl₃ führt zu einem Gemenge von Amiden der diastereomeren 3-Amino-2,3-diphenylpropansäuren in nahezu gleichen Mengen. Die Konfiguration der gewonnenen Amide wird durch ihre Synthese aus den entsprechenden 3-Amino-2,3-diphenylpropansäuren und sekundären Aminen bewiesen.

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Reaction of the cyclohexylamide, dimethylamide and morpholide of phenylacetic acid with hydrobenzamide in the presence of anhydrous AlCl₃ yields a mixture of the amides of the diastereomeric 3-amino-2,3-diphenylpropanoic acids in nearly equal amounts. The configurations of the amides obtained have been proved by synthesis from the corresponding 3-amino-2,3-diphenylpropanoic acids and secondary amines.

     

New Heterocyclic Compounds Derived from 4,6‐Diamino‐3‐cyano‐2‐methylthiopyridine and their Biological Activity

Treatment of 4,6‐diamino‐3‐cyano‐2‐methylthiopyridine ( 1 ) with aqueous KOH or hydrazine hydrate afforded the corresponding nicotinamide 2 and pyrazolo[3,4‐b]pyridine 3 , respectively. Reaction of compound 1 with bromine, sulfuryl chloride, formaldehyde, or aromatic diazonium salts gave 5‐bromopyridine 4 , 5‐chloropyridine 5 , dipyridylmethane 6 , and azo dyes 7 , 8 , 9 , 10 , respectively. Compound 1 reacted with diketones to yield the corresponding butenylamino derivative 11 and amides 12 , 13 , 14 , 15 , respectively. Treatment of butanamide 13 with diazonium salts or a mixture of urea and aromatic aldehyde in the presence of drops of HCl as a catalyst yielded the corresponding arylhydrazones 16 , 17 , 18 , 19 , pyrimidines 20 , 21 , 22 , 23 , 24 , and 1,8‐naphthyridine 25 , respectively. The potency of the results as anti‐inflammatory and antifungal agents have been evaluated. The compounds have been characterized based on their spectral and elemental analysis.     

Synthesis of new substituted acetamide derivatives of 6′,7′-dimethoxy-2′,3′-dihydro-1′<Emphasis Type="Italic">H</Emphasis>-spiro[isoquinoline-1,4′-cyclopentane]-1′-carboxamide

Reaction of ethyl 6′,7′-dimethoxy-3′Н-spiro[isoquinoline-1,4′-cyclopentane]-1′-carboxylate with ammonia and isopropylamine afforded dihydroisoquinoline carboxamides that were reduced with NaBH₄ in amides of 6,7-dimethoxy-4-spirocyclopentane-1,2,3,4-tetrahydroisoquinoline-1-carboxylic acid. The reaction of unsubstituted carboxamide with chloroacetyl chloride led to chloroamide that reacted with versatile secondary amines and heterylthiols providing the corresponding substituted amino- and sulfanylamides of tetrahydroisoquinoline series.     

Syntheses of substituted 2-(l-methyl-2-imidazolyl)quinolines

Reaction of methyllithium with 1-methy1-2-imidazolecarboxaldehyde afforded the corresponding alcohol 2. Oxidation of compound 2 with manganese dioxide gave 2-acety1-1-methylimidazole ( 3 ). Using compound 3 and substituted isatins 4 , the corresponding quinoline-4-carboxylic acids ( 5 ) were prepared. The reaction of acid imidazolides of 5 with appropriate amines yielded the amides 6 . Carbamic acid esters 10 were prepared by the Curtius rearrangement in good yield. Substituted quinolin-4-amines 13 were obtained by the acid hydrolysis of compound 10 (R₁ = t-Bu). Alkylation of amines 13 with diakylaminoalkyl chlorides gave compounds 14 .     

Dihydro-3-(triphenylphosphoranylidene)-2,5-thiophendione: A Convenient Synthon for the Preparation of Substituted 1,4-Thiazepin-5-ones and Piperidinones via the Intermediacy of Thioacids

Reaction of thiomaleic anhydride with triphenylphosphine gives the title compound, which undergoes reaction with a variety of aldehydes to give a range of alkylidene thiomaleic anhydrides (substituted monothioitaconic anhydrides). Subsequent treatment with tert-butoxycarbonylamino-substituted thiols, or under radical conditions with tert-butoxycarbonylamino-substituted alkyl halides results in a series of substituted monothiomaleic anhydrides, that on exposure to trifluoroacetic acid and then base lead to thiocarboxyl substituted 1,4-thiazepin-5-ones and piperidinones, respectively, that are ultimately trapped by reaction with 2,4-dinitrobenzenesulfonamides to give the corresponding amides.     

Highly enantiomerically enriched chlorophosphine boranes: synthesis and applications as P-chirogenic electrophilic blocks

The stereoselective synthesis of P-chirogenic chlorophosphine boranes 4 was investigated by HCl acidolysis of the corresponding aminophosphine boranes 10. The reaction afforded the P-N bond cleavage with inversion of the configuration at the phosphorus center, leading to the chlorophosphine boranes 4 with high to excellent enantiomeric purities (80-99% ee), except in the case of the chloro-1-naphthylphenylphosphine borane 4d. Reaction conditions and workup significantly influence the enantiomeric purity of the product, with the exception of the o-anisyl- and o-tolylchlorophenylphosphine boranes, 4b and 4c, which were found to be particularly stable even after purification by chromatography on silica gel. Reaction of the chlorophosphine boranes 4 with various nucleophiles, such as carbanions, phenolates, thiophenolates, or amides, afforded the corresponding organophosphorus borane complexes via P-C, P-O, P-S, and P-N bond formation, respectively, in 34-93% yield and with up to 99% ee. This work demonstrates the importance of chlorophosphine boranes 4 as new and powerful electrophilic building blocks for the highly stereoselective synthesis of P-chirogenic organophosphorus compounds.     

New routes to heterocycles via sulphenylation of unsaturated amides

Reaction of manganic acetate with organic disulphides in dichloromethane-trifluoroacetic acid in the presence of a variety of unsaturated amides leads to intramolecular cyclisation with formation of sulphenylated oxazolines, oxazines or tetrahydropyrroles.     

Is an iodine atom almighty as a leaving group for Bu(3)SnH-mediated radical cyclization? The effect of a halogen atom on the 5-endo-trig radical cyclization of N-vinyl-alpha-halo amides

The effect of a halogen atom as a leaving group on Bu(3)SnH-mediated 5-endo-trig radical cyclization of N-(cyclohex-1-enyl) alpha-halo amides was examined. The cyclization of alpha-chloro amides occurred with a high degree of efficiency, whereas the corresponding alpha-iodo congeners gave only limited quantities of cyclization products. A detailed study revealed that these phenomena could be attributed to the initial conformations of alpha-halo amides. The cyclizing ability of alpha-iodo amides can be restored with Bu(3)SnCl or Bu(3)SnF as an additive. The cyclization of an alpha-iodo amide in the presence of Bu(3)SnF could be applied to a short-step synthesis of lycoranes featuring sequential 5-endo-trig and 6-endo-trig radical cyclizations.     

Reaction of <Emphasis Type="Italic">N,N</Emphasis>-dichlorosulfonamides with tribromoethylene

Reaction of aryl-and trifluoromethanesulfonic acids N,N-dichloroamides with tribromoethylene led to the formation of a mixture of N-(2,2-dibromo-2-chloroethylidene)-and N-(2,2,2-tribromoethylidene)amides of the corresponding sulfonic acids. The azomethines ratio is governed by the reaction temperature.