Convenient Preparation of N,N′‐Diphenyl‐N,N′‐bis(4‐aminophenyl)‐p‐phenylenediamine

Abstract

This article describes modified conditions to prepare N,N′‐diphenyl‐N,N′‐bis(4‐aminophenyl)‐P‐phenylenediamine in 60% overall yield.     

Synthesis of N‐Aryl‐2‐substituted Tetrahydrobenzimidazoles via Direct N‐Arylation

A series of novel N‐aryl‐2‐substituted tetrahydrobenzimidazoles has been synthesized via direct N‐arylation of 2‐substituted tetrahydrobenzimidazoles, which was accomplished by a medium aryl electrophile, 4‐methylsulfonylfluorobenze, in the presence of 37% KF/Al₂O₃ and 18‐crown‐6 in fair yields under mild reaction conditions. Meanwhile, the hydrogenation of 2‐phenylbenzimidazole was studied.     

New Method of Synthesizing N‐Alkoxycarbonyl‐N‐arylamide with Triphosgene

N‐Chloroformyl‐N‐arylcarbamate, the key intermediate for the synthesis of some excellent pesticides, was synthesized through a new method with triphosgene instead of toxic phosgene. It cannot be obtained through the traditional method using triethylamine as a nucleophile. When triethylamine was replaced by a stronger base, sodium hydride, the product was obtained in good yield.     

Synthesis and Amphiphilic Behavior of N,N‐Bis‐glucosyl‐1,5‐benzodiazepin‐2,4‐dione

Abstract

Glucosyl‐1,5‐benzodiazepin‐2,4‐diones were synthesized in order to study the influence of the glucidic moiety on the amphiphilic behaviour. The glucosyl groups include 6‐deoxy‐D‐glucopyranos‐6‐yl and 6‐deoxy‐3‐O‐R‐D‐glucopyranos‐6‐yl (R = n ? C _n H _2n+1; n = 1, 8, 10 and 12). Variation in the length of the hydrocarbon chain allowed comparison of such amphiphilic data as water solubility (Sw) and surface tension (γ) values. At 25°C, the glucopyranosyl benzodiazepines with R = H and CH₃ show a higher water solubility than the starting 1,5‐benzodiazepin‐2,4‐diones. Some other glucidic benzodiazepine derivatives with an appropriate alkyl chain at C‐3 carbon of the D‐glucopyranose present a variable hydrosolubility and surface tension γ values close to 43 to 46 mN · m^?1 at the corresponding saturation. Moreover, according to preliminary tests, these compounds seem to show a better affinity for the blood brain barrier.     

One‐Pot Synthesis of Ene‐Lactams via N‐Debenzylation of Keto‐Containing N‐2,4‐Dimethoxylbenzylamides

Abstract

A general method of ene‐lactam preparation is described. Ene‐lactams can be prepared efficiently from keto‐containing N‐2,4‐dimethoxylbenzylamides in good to excellent yields. This method is applicable for the preparation of substituted δ‐, γ‐, and ?‐ene‐lactams and bicyclic ene‐lactams.     

Superoxide‐Mediated Synthesis of N‐Aminoaziridines from N‐Aminoheterocycles and Olefins

Oxidation of 3‐amino‐2‐methyl‐4(3H)‐quinazolone and N‐aminophthalimide by superoxide ion generated in situ in the presence of olefinic substrates gives rise to the formation of N‐aminoaziridine derivatives.     

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 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 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 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.     

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.     

Efficient Synthesis of 2‐(N‐Substituted)‐2‐imidazolines and 2‐(N‐Substituted)‐1,4,5,6‐tetrahydropyrimidines

A general method for the preparation of 2‐(N‐Substituted)‐2‐imidazolines and 2‐(N‐Substituted)‐1,4,5,6‐tetrahydropyrimidines is described. These heterocycles can be synthesized from their respective anilines with 2‐chloro‐2‐imidazoline or 2‐chloro‐1,4,5,6‐tetrahydropyrimidine, generated in situ from imidazolidin‐2‐one and tetrahydropyrimidin‐2(1H)‐one activated by dimethyl chlorophosphate, in good to excellent yields.     

Strategies towards the Synthesis of 6‐N,N‐Diethylcarbamyloxy‐1,4‐dimethoxy‐ 7‐naphthylboronic Acid

After acetylation, condensation between Danishefsky's diene and benzoquinone afforded a stable methoxytriacetoxydihydronaphthalene intermediate, which was subsequently transformed by the Snieckus DOM protocol into the regiospecific 7‐naphthylboronic acid.     

Solid‐Phase Synthesis of N‐Aryl‐N′‐Carboalkoxy Guanidines by the Mitsunobu Reaction of Fmoc‐Guanidines

Abstract

A new method for the solid‐phase synthesis of N‐aryl‐N′‐carboalkoxy guanidines is described. Aromatic amines were reacted with Fmoc‐isothiocyanate to provide Fmoc‐thioureas, which were coupled with Rink amide resin to provide the corresponding resin‐bound Fmoc‐guanidines. Subsequent Mitsunobu alkylation with a variety of alcohols delivered N‐aryl‐N′ carboalkoxy guanidines in good to high purity after resin cleavage.     

N‐Glycosyl‐N′‐[p‐(isoamyloxy)phenyl]‐thiourea Derivatives: Potential Anti‐TB Therapeutic Agents

Thiocarlide (THC; N,N′‐bis[p‐(isoamyloxy)phenyl]‐thiourea; also known as Isoxyl^®) has been used in the past as an anti‐tuberculosis agent. In an effort to improve the therapeutic value of THC, several N‐glycosyl‐N′‐[p‐(isoamyloxy)phenyl]‐thiourea derivatives were synthesized by coupling an aniline derivative and glycosyl isothiocyanates. The minimum inhibitory concentration (MIC) values of the new products against M. tuberculosis were determined.     

Microwave‐Assisted Synthesis of N,N′‐Disubstituted Acetamidine Ligands

Under microwave activation, triethylorthoacetate reacts with the substituted anilines in the presence of acetic acid as a catalyst, producing acetamidine in moderate to high yields. The X‐ray structures of the new amidines, N,N′‐bis(3,5‐dimethylphenyl)‐acetamidine and N,N′‐bis(p‐tolyl)acetamidine, are also reported, revealing polymeric chains supported by intramolecular H‐bonds.     

Preparation of 2‐Amino‐1,3‐butadienes as N‐Pyridine Derivatives

2‐Amino‐1,3‐butadienes as pyridine derivatives have been prepared from corresponding dihydrothiazolo[3,2‐a]pyridinium salts in reactions with a strong base. The pyridinium salts were prepared from pyridine‐2(1H)‐thiones and trans‐1,4‐dibromo‐2‐butene by a vicinal and chemoselective formation of 3‐vinyldihydrothiazolo[3,2‐a]pyridinium salts. A strong base was used for selective proton removal from the vinyl‐substituted 3‐position. A subsequent ring opening provided 2‐substituted 1,3‐butadienes with the azine appended at the annular nitrogen. Simple S‐alkylation yielded a corresponding azinium salt, thereby introducing electrophilic character to the 1,3‐butadiene system. Hydrolysis of the sulfide function provided the corresponding pyridin-2(1H)‐one attached to the 1,3‐butadiene in the 2‐position.     

Synthesis of Tetra‐O‐acetyl‐1‐thio‐α‐d‐glucopyranose by Reaction of Tetra‐O‐acetyl‐α‐d‐glucopyranosyl Bromide with N,N‐Dimethylthioformamide

A reaction system was found to prepare tetra‐O‐acetyl‐1‐thio‐d‐glycopyranose in both α and β‐forms. Methanolysis of the adduct prepared from the reaction of tetra‐O‐acetyl‐α‐d‐glucopyranosyl bromide with N,N‐dimethylthioformamide afforded the corresponding tetra‐O‐acetyl‐1‐thio‐d‐glucopyranose with an anomer ratio α/β of 52:48 in 98% yield. The anomer mixture was easily separated by column chromatography to obtain the product of α‐form. This synthetic method is very convenient to proceed by one‐pot reaction under ordinary conditions.     

Synthesis of N‐Protected/Free Indole‐7‐Carboxaldehyde

A direct method for the preparation of N‐protected/free indole‐7‐carboxaldehyde is reported from the corresponding N‐protected 7‐bromomethylindoles using three different conditions.     

1,1,3,3‐N,N,N′,N′‐Tetramethylguanidinium Trifluoroacetate Ionic Liquid–Promoted Efficient One‐Pot Synthesis of Trisubstituted Imidazoles

Trisubstituted imidazoles have been synthesized in very short reaction times with excellent yields in the presence of 1,1,3,3‐N,N,N′,N′‐tetramethylguanidinium trifluoroacetate as an ionic liquid at 100°C. The ionic liquid can be recycled for subsequent reactions without any appreciable loss of efficiency.