Aza-Wittig reaction of fluoroalkylated N-vinylic phosphazenes with carbonyl compounds. Usefulness of 2-azadienes for the preparation of fluoroalkyl pyridine derivatives

A method for the preparation of 3-fluoroalkyl substituted 2-aza-butadienes 6 by aza-Wittig reaction of 3-fluoroalkyl-N-vinylic phosphazenes 4 and aldehydes 5 is reported. [4+2] Cycloaddition reaction of these heterodienes 6 with enamines 9 gives fluoroalkyl substituted pyridine 15, 16, 24-27 and isoquinoline 12-14, 20 derivatives.     

Synthesis of substituted 2-amino-5,6-dihydropyrimidin-4-ones using an aza-Wittig reaction

An aza-Wittig reaction has been used for the first time in the synthesis of substituted 2-amino-5,6-dihydropyrimidin-4-ones via condensation of triphenyliminophosphoranes with aromatic heterocumulenes (arylisocyanates and thiocyanates). __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1037–1041, July, 2006.     

Regioselective synthesis of pyridines and dihydropyridines derived from β-amino acids and aminophosphonates by reaction of N-vinylic phosphazenes with α,β-unsaturated ketones

Reaction of N-vinylic phosphazenes with α,β-unsaturated ketones leads to the formation of pyridines derived from β-amino acids in a regioselective fashion. The use of functionalized enones derived from α-acylstyryl-carboxylates or -phosphonates affords biologically active asymmetrical and symmetrical dihydropyridines substituted with carboxylate or phosphonate groups including nitrendipine, felodipine, MRS 1097, and efonidipine analogs.     

Cycloaddition reaction of 2-azadienes derived from beta-amino acids with electron-rich and electron-deficient alkenes and carbonyl compounds. Synthesis of pyridine and 1,3-oxazine derivatives

Functionalized keto-enamines 6 were obtained by nucleophilic addition of enol ethers to the imine moiety of 2-azadienes derived from dehydroaspartic esters 4. Reactions of 2-azadiene 4c containing three electron-withdrawing substituents (CO(2)R) with enol ethers 5 in the presence of lithium perchlorate led to the formation of tetrahydropyridine derivatives 7 in a regio- and stereoselective fashion. 2H-[1,3]-oxazines 10 and pyridine derivatives 12 and 13 were obtained by heterocycloaddition reactions of electron-poor azadienes 4d-g containing two electron-withdrawing substituents (4-O(2)N-C(6)H(4), CO(2)R) in positions 1 and 4 with carbonyl derivatives (ethyl glyoxalate 9a and diethyl ketomalonate 9b) and the electron-deficient olefin tetracyanoethylene 11.     

Phosphorus–nitrogen compounds. Part VI. Aminolysis of octachlorocyclotetraphosphazatetraene and the crystal structure of 2-trans-6-bis(n-propylamino)-2,4,4,6,8,8-hexakis-tert-butylaminocyclo-2λ, 4λ, 6λ, 8λ-tetraphosphazatetraene

The reactions of 2-trans-6-N₄P₄(NHPrⁿ)₂Cl₆ (2), which was obtained from N₄P₄Cl₈ (1) and n-propylamine, with pyrrolidine and t-butylamine in different solvents have been studied. Compound (2) gave two different products, namely monocyclic (3 and 5) and bicyclic (4 and 6) phosphazenes. Compounds (2–6) have been characterized by elemental analysis, IR, ¹H-, ¹³C-, ³¹P NMR, HETCOR and MS and the structure of compound (5) has been examined crystallographically. The bicyclic phosphazene (6) is the first exciting example of bicyclic phosphazenes containing chlorine atoms, in the literature. The formation mechanisms of bicyclic phosphazenes are re-considered by taking into account the synthesis of compound (6), which contains three stereogenic phosphorus atoms. Compound (5) crystallizes in the monocyclic space group P2₁/n with a=13.974(2), b=17.836(5), and c=18.683(4) Å, β=98.50(1)°, V=4605.4(2) Å³, Z=4 and D_x=1.051 g cm^−3. It consists of a non-centrosymmetric, non-planar phosphazene ring in a saddle conformation, with two n-propylamino (in 2-trans-6 positions) and six bulky t-butylamino side groups. The bulky substituents are instrumental in determining the molecular geometry.     

2-烷氧基-3H-喹唑啉-4-酮的合成与杀菌活性

研究了合成2-烷氧基-3H-喹唑啉-4-酮衍生物4的方法,该方法应用膦亚胺1与芳基异氰酸酯的氮杂Wittig反应,得到的碳二亚胺2再与醇在醇钠催化下反应,合成了12种未见文献报道的喹唑啉酮衍生物4.所得产物4的结构由NMR,MS,IR所确证.探讨了成环反应的条件以及所合成的新型杂环化合物的杀菌活性,结果表明部分化合物表现出较好的抑菌活性,如41在50 mg/L浓度时,对水稻纹枯菌的抑制率为89%.     

A Facile Synthesis of 2-Mino-3H-Quinazolin-4-Ones with Tandem Aza-Wittig Reaction

2-Amino-3H-quinazolin-4-ones 8 were prepared from tandem aza-Wittig reaction of iminophosphorane 5 with aromatic isocyanate and nucleaphilic reagent HY in mild condition.     

N-tert-Butylbenzenesulfenamide-catalyzed oxidation of alcohols to the corresponding carbonyl compounds with N-chlorosuccinimide

N-tert-Butylbenzenesulfenamide (1)-catalyzed oxidation of various primary and secondary alcohols to the corresponding aldehydes and ketones was efficiently carried out by using N-chlorosuccinimide (NCS) in the coexistence of potassium carbonate and molecular sieves 4 Å at easy-to-control temperatures ranging from 0°C to room temperature. The present catalytic oxidation was performed without giving any damage to the functional groups in alcohols, and was particularly effective in the oxidation of alcohols that formed labile aldehydes because of its mild reaction conditions. Further, selective oxidation of primary hydroxy groups took place in 1-catalyzed oxidation of several diols. Mechanistic investigation suggested that the chlorination of the sulfenamide 1 by NCS led to the formation of a key species, N-tert-butylbenzenesulfinimidoyl chloride (2), which in turn oxidized alcohols in the presence of potassium carbonate to afford carbonyl products by accompanying regeneration of the catalyst 1.     

Photoreactions of benzosilacyclobutenes with carbonyl compounds. SH2 reaction on SiC bond by triplet carbonyl compounds

Photoreaction of 2,3-benzo-1,1-diphenyl(or dimethyl)-1-sila-2-cyclobutene with an aldehyde or ketone results in 1:1 cycloadduct of [4+2] type, the formation of which is accountd for in terms of S_H2 process, i.e., attack of a triplet carbonyl compound on the silicon of the benzosilacyclobutene.     

The Synthesis of 2-Alkylthio-3-alkyl-5-arylmethylidene4H-imidazol-4-ones

2-alkylthio-3-alkyl-5-arylmethylidene-4H-imidazol-4-ones were synthesized by the S-alkylation and N-alkylation of 2-thioxo-5-arylmethylidene-4-imidazolidinones, which were obtained via a tandem aza-Wittig reaction of vinyliminophosphoranes, carbon disulfide, and excess ammonium hydroxide (28% NH₃ in water).     

Reactions of isocyanatophosphoryl difluoride with π-abundant nitrogen heterocycles and carbonyl compounds

Reactions of electron-rich nitrogen heterocycles with isocyanatophosphoryl difluoride were studied. Novel heteroylaminophosphoryl difluorides were obtained in high yields. N-Phosphorylated imines were synthesized for the first time from carbonyl compounds and phosphorus isocyanates. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 564–566, March, 2006.     

Reactions of N-vinylic phosphazenes with azodicarboxylic and acetylenic esters

N-Vinylic phosphazenes react as enamines (1,4-addition) with azodicarboxylic esters, whereas different behavior is observed when these phosphazenes react with dimethyl acetylenedicarboxylate (3,4-addition). A [2+2] cycloaddition reaction of the vinyl moiety of vinylic phosphazenes with the acetylenic triple bond of the acetylenic esters followed by a ring opening leads to the formation of functionalized conjugated phosphazenes.     

Rhodium/Silver‐Cocatalyzed Transannulation of N‐Sulfonyl‐1,2,3‐triazoles with Vinyl Azides: Divergent Synthesis of Pyrroles and 2 H‐Pyrazines

The first cyclization reaction between vinyl azides and N‐sulfonyl‐1,2,3‐triazoles is reported. A Rh/Ag binary metal catalyst system proved to be necessary for the successful cyclization. By varying the structure of vinyl azides, such reaction allows the divergent synthesis of pyrroles and 2H‐pyrazines. The cyclization reactions feature a broad substrate scope, good functional group tolerance, high reaction efficiency, and good to high product yields.     

A diastereoselective aza-Diels-Alder reaction of N-aryl-1-azadienes derived from α-amino acids with enamines

A diastereoselective inverse electron demand aza-Diels-Alder reaction of N-aryl-1-azadienes derived from α-amino acids is accomplished using enamine dienophiles. Activation with ytterbium triflate of these azadienes affords dimeric structures through aza-Diels-Alder reaction, where the alkene double bond of 1-azadienes also adopts the role of dienophile. An asymmetric synthesis of functionalised 1,4,5,6-tetrahydropyridine compounds derived from α-amino acids using an optically active enamine is reported.     

Synthesis of 2-amino-3-cyano-4H-chromen-4-ylphosphonates and 2-amino-4H-chromenes catalyzed by tetramethylguanidine

Synthesis of 2-amino-4H-chromen-4-ylphosphonates and 2-amino-4H-chromenes has been accomplished by the reaction of salicylaldehyde, malononitrile, dialkyl/diphenylphosphites catalyzed by 1,1,3,3-tetramethylguanidine (TMG) under neat conditions at room temperature. The applicability of catalytic TMG for the synthesis of 2-amino-4H-chromenes also has been described. The mild reaction conditions, simple work-up procedure, and use of TMG as an inexpensive catalyst provides an economical protocol for the preparation of important phosphorus-containing compounds.     

Synthesis of pseudopeptidic (S)-6-amino-5-oxo-1,4-diazepines and (S)-3-benzyl-2-oxo-1,4-benzodiazepines by an Ugi 4CC Staudinger/aza-Wittig sequence

Sequential Ugi reaction between p-substituted arylglyoxals, alkylamines, cyclohexyl isocyanide and 3-azido-(S)-2-(tert-butoxycarbonylamino)propanoic acid, followed by a Staudinger/aza-Wittig cyclization in the presence of triphenylphosphine, gave rise to enantiomerically pure N-cyclohexyl 4-alkyl-2-aryl-5-oxo-(S)-6-(tert-butoxycarbonylamino)-4,5,6,7-tetrahydro-1H-1,4-diazepine-3-carboxamides, that can be useful for new drug design. By the same sequence, p-substituted benzaldehydes, 2-aminobenzophenone, cyclohexyl isocyanide and (S)-3-phenyl-2-azidopropionic acid gave rise to N-cyclohexyl 2-((S)-3-benzyl-2-oxo-5-phenyl-2,3-dihydro-1H-benzo[e][1,4]diazepin-1-yl)-(R/S)-2-arylacetamides.     

On the reaction of 2-amino-4-thiazoliniminium salts with active methylene compounds

Summary The easily available 2-amino-4-thiazoliniminium salts6 react with different types of active methylene compounds. Whereas 2-amino-4-cyanomethylene-4,5-dihydrothiazoles13 and14 are formed with malononitrile (11) or ethyl cyanoacetate (12) in the presence of bases, acetyl acetone (15) and ethyl acetic acetate (16) afford 2-amino-thiazolo[4,5-b]pyridines21 and22, resp. The structures of the new compounds13, 14, 21 and22 have been elucidated by means of analytical and spectroscopic methods and confirmed by some chemical reactions.

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Reaktion von 2-Amino-4-thiazoliniminium-Salzen mit aktivierten Methylenverbindungen

Zusammenfassung Durch Reaktion der einfach zugänglichen 2-Amino-4-thiazoliniminium-Salze6 mit Malonsäuredinitril (11) oder Cyanessigsäureethylester (12) in Gegenwart von Basen werden die 2-Amino-4-cyanmethylen-4,5-dihydrothiazole13 bzw.14 gebildet, während mit Acetylaceton (15) und Acetessigsäureethylester (16) auf analoge Weise die 2-Aminothiazolo[4,5-b]pyridine21 bzw.22 entstehen. Die Strukturen der neu dargestellten Verbindungen des Typs13, 14, 21 und22 wurden spektroskopisch abgesichert und durch einige Folgereaktionen bestätigt.

     

Unusual reaction of beta-hydroxy alpha-diazo carbonyl compounds with Cl3CCN/NaH and Rh(II)-catalyzed reaction of beta-trichloroacetylamino alpha-diazo carbonyl compounds

The hydroxyl group was directly converted into the trichloroacetylamino group by reacting beta-hydroxy alpha-diazo carbonyl compounds with Cl(3)CCN and NaH. Rh(II)-catalyzed reactions of the beta-amino alpha-diazo carbonyl compounds were discussed. [reaction: see text]     

Synthesis of β-amino carbonyl compounds via a Zn(OTf)2-catalyzed cascade reaction of anilines with aromatic aldehydes and carbonyl compounds

A Zn(OTf)₂-catalyzed cascade reaction of anilines with aromatic aldehydes and carbonyl compounds was described. This one-pot three-component reaction afforded the corresponding β-amino carbonyl compounds, β-amino esters, and β-amino ketones in good to excellent yields. The reaction was also applied for the liquid-phase synthesis of β-amino carbonyl compound library using PEG as a support.     

The Reaction of (N-Isocyanimino)triphenylphosphorane with Anthranilic Acid Derivatives: One-Pot Synthesis of 2-Substituted 1,3,4-Oxadiazoles via Intramolecular Aza-Wittig Reaction

The reaction of anthranilic acid derivatives with (N-isocyanimino)triphenylphosphorane proceeds smoothly at room temperature to afford 2-substituted 1,3,4-oxadiazoles via an intramolecular aza-Wittig reaction in excellent yields under neutral conditions. The structures of the products were deduced from their IR, ¹H NMR, and ¹³C NMR spectra and mass spectrometry.