Synthesis of 1,2,4‐Triazinediones, 1,2,4,3‐Triazaphospholines,and 1,2,4,3‐Triazaphospholine‐3‐oxide Derivatives

The reaction of N ¹‐tosylamidrazones 1 with oxalyl dichloride, phosphorus trichloride, and phosphoryl chloride leads to 1,2,4‐triazinediones 3 , 1,2,4,3‐triazaphospholines 4 , and 1,2,4,3‐triazaphospholine‐3‐oxides 5 , respectively. The structures of the new products have been established by IR; ¹H, ¹³C, and ³¹P NMR studies; and elemental analysis.     

Formation of 1,2,5‐Oxadiazole,Isoxazole, Isothiazole, 1,2,3‐Triazole,and Pyrrole Rings from N‐(5,5‐Dimethyl‐3‐oxocyclohexenyl)‐S,S‐diphenylsulfilimine

Reactions of N‐(5,5‐dimethyl‐3‐oxocyclohexenyl)‐S,S‐diphenylsulfilimine, a kind of enaminone, with isopentyl nitrite, isocyanates, isothocyanates, benzenediazonium chloride, and 1,1,1‐trifluoro‐4‐ethoxy‐3‐buten‐2‐one gave 1,2,5‐oxadiazole, isoxazole, isothiazole, 1,2,3‐triazole, and pyrrole derivatives condensed with cyclohexane, respectively, in one pot.     

Synthesis of Novel (3a,S)‐1‐Aryl/aryloxy/alkoxy‐3a,4‐dihydro‐3H‐1λ5‐[1,3,2]oxazaphospholo [3,4‐a] indole‐1‐ones,Thiones, and Selenones

Synthesis of novel (3a,S)‐1‐aryl/aryloxy/alkoxy‐3a,4‐dihydro‐3H‐1λ⁵‐[1,3,2]oxazaphospholo [3,4‐a] indole‐1‐ones, thiones, and selenones was achieved in two steps with high yields from 2,3‐dihydro‐1H‐indol‐2(S)yl methanol (1) and dichlorophenyl phosphine/ethyl dichlorophosphite (2a and b) in the presence of triethylamine in dry THF followed by treatment with hydrogen peroxide, sulfur, and selenium. The compounds 4g–k have been synthesized by the direct cyclocondensation of 1 with different substituted phenyl phosphorodichloridates (2c–e, g) and bis(2‐chloroethyl) phosphoramidic dichloride (2f).     

Regioselective Endocyclic Oxidation of Enantiopure 3‐Alkylpiperidines: Synthesis of (3S,5S)‐(‐)‐3‐Ethyl‐5‐Methylpiperidine

An efficient regioselective endocyclic oxidation of enantiopure 3‐alkylpiperidines 1(a–c) with bromine in acetic acid to generate the corresponding 5‐alkylpiperidin‐2‐ones 3(a–c) as main product is described. In addition, starting from 3a or 3b, the synthesis of (3S,5S)‐(‐)‐3‐ethyl‐5‐methylpiperidine 6 · HCl was achieved. Finally, the X‐ray single‐crystal analysis of compound 4 is reported.     

Reaction of Imines with 5,5‐Dimethyl‐1, 3‐cyclohexandione

The reaction of imines 1 with 5,5‐dimethyl‐1,3‐cyclohexandione 2 in methanol was investigated. When the reaction was carried out without a catalytic amount of molecular iodine, ring‐opening derivatives of xanthenediones 3 were obtained in high yields. On the other hand, when molecular iodine and a catalytic amount of zinc powder were employed as the catalyst, xanthenediones derivatives 4 were obtained with excellent yields.     

Copolymers of 2‐(3‐(6‐tetralino)‐3‐methyl‐1‐cyclobutyl)‐2‐Hydroxyethyl Methacrylate with Acrylonitrile and 4‐Vinylpyridine: Synthesis,Characterization, and Monomer Reactivity Ratios

The copolymerization of 2‐(3‐(6‐tetralino)‐3‐methyl‐1‐cyclobutyl)‐2‐hydroxyethyl methacrylate (TCHEMA), monomer with acrylonitrile and 4‐vinylpyridine were carried out in 1,4‐dioxane solution at 65°C using AIBN as an initiator. The copolymers were characterized by FTIR, ¹H‐NMR, and ¹³C‐NMR spectroscopic techniques. Thermal properties of the polymers were also studied by thermogravimetric analysis and differential scanning calorimetry. The copolymer compositions were determined by elemental analysis. The monomer reactivity ratios were calculated by the Fineman‐Ross and Kelen‐Tüdös method. Also, the apparent thermal decomposition activation energies were calculated by the Ozawa method with a Shimadzu TGA 50 thermogravimetric analysis thermobalance.     

Synthesis of the Potassium Channel Opener (3S,4R)‐3,4‐Dihydro‐4‐(2,3‐dihydro‐2‐methyl‐3‐oxo‐pyridazin‐6‐Yl)oxy‐3‐hydroxy‐6‐(3‐hydroxyphenyl)sulphonyl‐2,2,3‐trimethyl‐2H‐benzo[b]pyran

The preparation of the potassium channel opener (3S,4R)‐3,4‐dihydro‐4‐(2,3‐dihydro‐2‐methyl‐3‐oxo‐pyridazin‐6‐yl)oxy‐3‐hydroxy‐6‐(3‐hydroxyphenyl)sulphonyl‐2,2,3‐trimethyl‐2H‐benzo[b]pyran (1) as a single enantiomer is reported. Considerable improvements have been implemented with respect to the original synthesis that allow for the preparation of multigram quantities of the final target compound. The optimized synthesis consists of a six‐step linear sequence whose key step is an asymmetric epoxidation protocol through the use of Jacobsen's (S,S)‐(+)‐N,N′‐bis(3,5‐di‐tert‐butylsalicylidene)‐1,2‐cyclohexanediaminomanganese(III) chloride catalyst.     

From Tri‐O‐Acetyl‐D‐Glucal to (2R,3R,5R)‐2,3‐Diazido‐5‐Hydroxycyclohexanone Oxime

Abstract

Methyl 3‐azido‐2,3‐dideoxy‐α/β‐D‐arabino‐ and ‐α/β‐D‐ribo‐hexopyranosides were transformed into 6‐iodo analogues via p‐tolylsulfonyl compounds. Elimination of hydrogen iodide from 6‐iodo glycosides provided methyl 4‐O‐acetyl‐3‐azido‐2,3,6‐trideoxy‐α‐ and ‐β‐D‐threo‐hex‐5‐eno‐pyranosides or 3‐azido‐4‐O‐p‐tolylsulfonyl‐2,3,6‐trideoxy‐α‐D‐threo‐ and ‐β‐D‐erythro‐hex‐5‐eno‐pyranosides. Ferrier's carbocyclization of 4‐O‐acetyl‐3‐azido‐2,3,6‐trideoxy‐α‐ and ‐β‐D‐threo‐hex‐5‐eno‐pyranosides gave (2S,3R,5R)‐2‐acetoxy‐3‐azido‐5‐hydroxycyclohexanone, which was converted into oxime. The 2‐OAc group in oxime was substituted by azide ion to yield (2R,3R,5R)‐2,3‐diazido‐5‐hydroxycyclohexanone oxime. The configuration and conformation of all products are widely discussed on the basis of the ¹H and ¹³C NMR.     

SbCl3‐Al2O3–Catalyzed,Solvent‐Free,One‐Pot Synthesis of Benzo[b]1,4‐diazepines

This article explores the use of antimony(III) chloride adsorbed on neutral alumina as an efficient catalyst for the one‐pot synthesis of benzo[b]1,4‐diazepines (83–94%) under solvent‐free conditions. The process is easy, efficient, ecofriendly, and economical.     

Substituted Quinolinones,Part 11: Efficient Synthesis of Different 3‐(4‐Arylidene and Hetarylidene‐5‐oxopyrazolin‐3‐yl) quinolin‐2‐ones

Several 3‐(4‐arylidene and hetarylidene‐5‐oxopyrazolin‐3‐yl)quinolin‐2‐ones 6–26 were synthesized in an efficient methodology utilizing both pyrazolinylquinolinone 2 and its chromenylmethylene derivative 10. Compound 2 was derivatized by Knoevenagel condensation with different carbonyl compounds. Nucleophilic ring opening–ring closure (RORC) of the compound 10 furnished the desired 4‐methylenepyarzolinone bearing novel five‐, six‐, and seven‐membered heterocycles, in good yields.     

Novel Copolymers of Styrene and Some Ring‐Substituted 2‐Cyano‐N,N‐Dimethyl‐3‐Phenyl‐2‐Propenamides

Electrophilic trisubstituted ethylene monomers, ring‐substituted 2‐cyano‐N,N‐dimethyl‐3‐phenyl‐2‐propenamides, RC₆H₄CH?C(CN)CON(CH₃)₂ (where R is 3‐benzyloxy, 4‐benzyloxy, 3‐ethoxy‐4‐methoxy, 3‐bromo‐4‐methoxy, 5‐bromo‐2‐methoxy, 2‐chloro‐6‐fluoro) were synthesized by potassium hydroxide catalyzed Knoevenagel condensation of ring‐substituted benzaldehydes and N,N‐dimethyl cyanoacetamide, and characterized by CHN elemental analysis, IR, ¹H‐ and ¹³C‐NMR. Novel copolymers of the ethylenes and styrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator, ABCN at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H and ¹³C NMR, GPC, DSC, and TGA. High T_g of the copolymers in comparison with that of polystyrene indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. The gravimetric analysis indicated that the copolymers decompose in the 300–450°C range.     

Novel Copolymers of Styrene and Halogen Ring‐Substituted 2‐Cyano‐N,N‐Dimethyl‐3‐Phenyl‐2‐Propenamides

Electrophilic trisubstituted ethylene monomers, halogen ring‐substituted 2‐cyano‐N,N‐dimethyl‐3‐phenyl‐2‐propenamides, RC₆H₄CH [dbnd]C(CN)CON(CH₃)₂ (where R is 2‐Br, 3‐Br, 4‐Br, 2‐Cl, 3‐Cl, 4‐Cl, 2‐F, 3‐F, 4‐F), were synthesized by potassium hydroxide catalyzed Knoevenagel condensation of ring‐substituted benzaldehydes and N,N‐dimethyl cyanoacetamide, and characterized by CHN elemental analysis, IR, ¹H‐ and ¹³C‐NMR. Novel copolymers of the ethylenes and styrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator, ABCN at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H and ¹³C NMR, GPC, DSC, and TGA. High T _g of the copolymers in comparison with that of polystyrene indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. The gravimetric analysis indicated that the copolymers decompose in the 300–450°C range.     

Novel Copolymers of Styrene and Some Ring‐Substituted 2‐Cyano‐N,N‐Dimethyl‐3‐Phenyl‐2‐Propenamides

Electrophilic trisubstituted ethylene monomers, ring‐substituted 2‐cyano‐N,N‐dimethyl‐3‐phenyl‐2‐propenamides, RC₆H₄CH?C(CN)CON(CH₃)₂ (where R is 4‐(CH₃)₂N, 4‐CH₃CO₂, 4‐CH₃CONH, 2‐CN, 3‐CN, 4‐CN, 4‐(C₂H₅)₂N) were synthesized by potassium hydroxide catalyzed Knoevenagel condensation of ring‐substituted benzaldehydes and N,N‐dimethyl cyanoacetamide, and characterized by CHN elemental analysis, IR, ¹H‐ and ¹³C‐NMR. Novel copolymers of the ethylenes and styrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator, ABCN at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H and ¹³C NMR, GPC, DSC, and TGA. High T_g of the copolymers in comparison with that of polystyrene indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. The gravimetric analysis indicated that the copolymers decompose in the 300–450°C range.     

Novel Copolymers of Styrene and Alkoxy Ring‐Substituted 2‐Cyano‐N,N‐Dimethyl‐3‐Phenyl‐2‐Propenamides

Electrophilic trisubstituted ethylene monomers, alkoxy ring‐substituted 2‐cyano‐N,N‐dimethyl‐3‐phenyl‐2‐propenamides, RC₆H₄CH?C(CN)CON(CH₃)₂ (where R is 2‐OCH₃, 3‐OCH₃, 4‐OCH₃, 2‐OCH₂CH₃, 3‐OCH₂CH₃, 4‐OCH₂CH₂CH₃, 4‐OCH₂CH₂CH₂CH₃), were synthesized by potassium hydroxide catalyzed Knoevenagel condensation of ring‐substituted benzaldehydes and N,N‐dimethyl cyanoacetamide, and characterized by CHN elemental analysis, IR, ¹H‐ and ¹³C‐NMR. Novel copolymers of the ethylenes and styrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator, ACBN at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H and ¹³C NMR, GPC, DSC, and TGA. High T_g of the copolymers in comparison with that of polystyrene indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. The gravimetric analysis indicated that the copolymers decompose in the 300–450°C range.     

Novel Copolymers of Styrene and Halogen Ring‐Disubstituted 2‐Cyano‐N,N‐Dimethyl‐3‐Phenyl‐2‐Propenamides

Electrophilic trisubstituted ethylene monomers, halogen ring‐disubstituted 2‐cyano‐N,N‐dimethyl‐3‐phenyl‐2‐propenamides, RC₆H₃CH?C(CN)CON(CH₃)₂ (where R is 2,3‐dichloro, 2,4‐dichloro, 2,6‐dichloro, 3,4‐dichloro, 3,5‐dichloro, 2,3‐difluoro, 2,4‐difluoro, 2,6‐difluoro, 3,4‐difluoro, 3,5‐difluoro), were synthesized by potassium hydroxide catalyzed Knoevenagel condensation of ring‐substituted benzaldehydes and N,N‐dimethyl cyanoacetamide, and characterized by CHN elemental analysis, IR, ¹H‐ and ¹³C‐NMR. Novel copolymers of the ethylenes and styrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator, ABCN at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H and ¹³C NMR, GPC, DSC, and TGA. High T_g of the copolymers in comparison with that of polystyrene indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. The gravimetric analysis indicated that the copolymers decompose in the 300–450°C range.     

Synthesis of 3‐Methoxyoxetane δ‐Amino Acids with D‐lyxo,D‐ribo,and D‐arabino Configurations

Starting from 1,2‐isopropylidene‐d‐xylose (1), 3‐methoxyoxetane δ‐amino acids with d‐lyxo, d‐ribo, and d‐arabino configurations were synthesized. The early introduction of an azide function at C‐5 of 1 shortened the synthetic pathway. Ring contraction of the intermediate d‐xylono‐1,4‐lactone 6 via triflation and treatment with base led to the corresponding 3‐methoxyoxetane δ‐amino ester with d‐lyxo configuration 7. The analogous procedure for d‐ribono‐1,4‐lactone 16 furnished a mixture of d‐ribo and d‐arabino esters 17 and 18. Hydrolysis of the methyl esters 7, 17, and 18 to their corresponding δ‐amino acids was successful with LiOH in THF, in contrast to that of their 3‐hydroxy analog 11.      

Exclusive Formation of 1‐Aryl‐3‐(5‐nitro‐2‐furyl)‐4‐aroylpyrazoles via Regiospecific 1,3‐Dipolar Cycloaddition of 3‐Arylsydnones with α,β‐Acetylenic Ketones

1,3‐Dipolar cycloaddition of 3‐arylsydnones with α,β‐acetylenic ketones containing nitrofuran moiety has been studied, and it was observed that the dipolar cycloaddition is regiospecific, forming 1‐aryl‐3‐(5‐nitro‐2‐furyl)‐4‐aroylpyrazoles exclusively.     

Improved Synthesis of 1‐Hydroxy‐2,2,5,5‐tetramethyl‐3‐imidazoline 3‐Oxide (HTIO)

A simple, efficient, mild, and reproducible method for the synthesis of 1‐hydroxy‐2,2,5,5‐tetramethyl‐3‐imidazoline 3‐oxide is described. The method is based on the condensation of 2‐hydroxyamino‐2‐methylpropanal oxime with 2,2‐diethoxypropane in the presence of an equimolar quantity of acetic acid. Cost‐effectiveness of the condensation procedure could be also achieved by replacing 2,2‐diethoxypropane with less expensive 2,2‐dimethoxypropane.     

Catalytic Oxidative Cyclocondensation of o‐Aminophenols to 2‐Amino‐3H‐phenoxazin‐3‐ones

The catalytic oxidative cyclocondensation of the o‐aminophenols 1a–f was investigated. The oxidants used were air/laccase, H₂O₂/horseradish peroxidase, H₂O₂/ebselen (3), and TBHP/diphenyl diselenide 4. The products obtained were 2‐amino‐3H‐phenoxazin‐3‐one—questiomycin A, its derivative 2b, and cinnabarinic acid and actinocin (2c,d). Substrates with methyl groups at 4 and 5 positions of benzene ring were converted to different dihydrophenoxazinones 2g,h. Compounds having chlorine atoms at the same positions underwent oxidation to planar phenoxa-zinones 2e,f with elimination of one hydrochloride molecule.     

Suzuki Coupling of 2‐Chloroacrylonitrile,Methyl 2‐Chloroacrylate,or 2‐Chloroprop‐1‐en‐3‐ol with Arylboronic Acids Catalyzed by a Palladium‐Tetraphosphine Complex

The tetraphosphine all‐cis‐1,2,3,4‐tetrakis(diphenylphosphinomethyl)cyclopentane (Tedicyp) in combination with [Pd(C₃H₅)Cl]₂ affords an efficient catalyst of the coupling of 2‐chloroacrylonitrile with arylboronic acids. In the presence of 1% catalyst, the 2‐arylacrylonitrile derivatives were obtained in medium to good yields. A variety of substituents such as alkyl, methoxy, fluoro, trifluoromethyl, formyl, or nitro on the arylboronic acid are tolerated. The cross‐coupling reactions of methyl 2‐chloroacrylate with arylboronic acids give simple access to 2‐phenylacrylate derivatives, which are useful precursors for the synthesis of biologically active compounds such as ibuprofen, ketoprofen, and naproxen.